WO2015168720A1

WO2015168720A1 - Wound sensor, system and method

Info

Publication number: WO2015168720A1
Application number: PCT/AU2014/000988
Authority: WO
Inventors: Nasir Mehmood; Alex HARIZ; Nicolas H. VOELCKER
Original assignee: University Of South Australia
Priority date: 2014-05-07
Filing date: 2014-10-20
Publication date: 2015-11-12

Abstract

Disclosed is a sensor device for sensing one or more parameters relating to a wound under a wound dressing. The sensor device provides the sensed data at an output of the sensor device for access by a user. In one form, the output is an active transmitter which transmits the sensed data to a remote device. Also disclosed is a sensor device platform to which one or more sensors are connectable. Also disclosed is a remote device for receiving sensed data from the sensor device. Methods of dressing a wound and obtaining data relating to a dressed wound are also disclosed.

Description

WOUND SENSOR, SYSTEM AND METHOD

TECHNICAL FIELD

[0001] The present application relates to devices and systems relating to treatment of wounds dressed with a wound dressing.

PRIORITY

[0002] The present application claims priority from Australian Provisional Patent Application No.

2014901689 titled "Wound Sensor".

[0003] The entire content of this application is hereby incorporated by reference. BACKGROUND

[0004] Chronic wounds such as venous leg ulcers, diabetic foot ulcers and pressure ulcers present a significant financial burden to the healthcare systems in the world. A current estimate shows the economic cost of wound care activities in the world is distributed as 15-20% materials, 30-35 % nursing time and more than 50 % as hospitalization time. The wound care cost in Australia alone is estimated at $ 2.6 billion per year with more man 4000 limb amputations. The Australian Institute of Health and Welfare report in 2012 shows that almost 6.5% of total diseases and 31 % of nursing activities were attributed to wounds during 201 . Activities contributing to these costs include the cost of community nurses traveling to patients to check on their dressings. A survey has indicated that the burden of a successful wound repair on a healthcare system might range from S75,000 to $90,000 per patient. This cost is on the rise throughout the world with an estimate of over $20 billion annually in die near future.

[0005] Healing Of wounds involves complex biochemical processes largely divided into four phases:

i) haemostasis, ti) inflammation, iii) proliferation, and iv) remodelling. A wound properly heals if all of these phases occur in their natural sequence. However, if one or more stages is prolonged for any reason, the healing process is impaired, resulting in delayed or non-healing wounds. Many factors contribute to impaired wound healing including oxygenation, age, gender, infection, diet, hormones, stress, diabetes and medications.

[0006] The most effective and economical way of treating wounds is to cover them with a suitable dressing in order to protect damaged skin from external effects such as microorganism attacks. For some chronic wounds such as venous ulcers, appropriate pressure bandages are also applied to absorb the wound exudate and to increase the healing rate. These bandages may be conforming (low pressure), light support (medium pressure) or compression (high pressure) bandages. The co 60 mmMg thai is regarded as extra high pressure, while the recommended high pressure value is about 40 mmHg.

Depending on the applied pressure range and the type of bandage used, the sub-bandage pressure produced may vary significantly during roe physical movement of roe patient, thus affecting the healing rate.

[0007] In addition to pressure bandages, healing rate may also be affected by retaining moisture to the wound site through moisture-retentive dressings. Conversely, excessive moisture in the dressing can lead to failure of the dressing.

10008) Additionally, wound site temperature and pH may also be used as an indication of infection.

[0009] In some chronic wounds, such as diabetic foot ulcers, excessive pressure at pressure points under the foot can also delay wound healing.

[0010] To d te, the changing of dressings in clinics and hospitals relies heavily on the individual experience of clinicians involved in wound care.

SUMMARY

[0011 ] According to a first aspect, there is provided a flexible sensor device comprising: at least one parameter sensor for placement under a wound dressing in use and for sensing a parameter under the wound dressing and generating sensed data; and an output for allowing the sensed data to be retrieved while the at least one parameter sensor remains under roe wound dressing.

[0012 J According to a second aspect, there is provided a sensor device comprising: at least one parameter sensor for placement under a wound dressing in use and for sensing a parameter under the wound dressing and generating sensed data; and an active wireless transmitter for receiving data from die at least one parameter sensor and for transmitting the sensed data to a remote receiver.

[0013] According to a third aspect, there is provided a sensor device comprising: at least one pressure sensor for placement under a wound dressing in use and for sensing pressure under the wound dressing and generating sensed data; and an output for allowing the sensed data to be retrieved while die at least one parameter sensor remains under the wound dressing.

[0014] According to a fourth aspect, there is provided a wound dressing incorporating at least one sensor device according to the first, second and third aspects.

[001 S] According to a fifth aspect, there is provided a method of dressing a wound of a patient with a wound dressing- the method comprising: placing at least one of the at least one pressure sensor of the sensor device of the third aspect on the patient, at or near the wound; and dressing the wound with the wound dressing including covering the at least one of the at least one pressure sensor with the wound dressing.

[0016] According to a sixth aspect, there is provided a method of dressing a wound of a patient with a wound dressing, the method comprising: placing at least one of the at least one parameter sensor of the sensor device of the first aspect on the patient, at or near the wound; and dressing the wound with the wound dressing including covering the at least one of die at least one parameter sensor with the wound dressing.

[0017] According to a seventh aspect, there is provided a method of obtaining sensed data of one or more parameters relating to a region under a wound dressing, the method comprising: receiving a wireless transmission from the active wireless transmitter of the sensor device according to any of the first, second and third aspects.

[ 0018] According to an eighth aspect, there is provided a method of obtaining sensed data of one or more parameters relating to a region under a wound dressing, the method comprising: wirclcssiy downloading the sensed data from the passive transmitter of the sensor device according to any one of the first or third aspects.

[0019] According to a ninth aspect, there is provided a method of obtaining sensed data of one or more parameters relating to a region under a wound dr i th th d i i connecting an electrical connector to the connector f the sensor device according to any one of the first or third aspects; and accessing the sensed data from the memory of die sensor device.

[0020] According to a tenth aspect, there is provided a system for obtaining sensed dam of one or more parameters relating to a region under a wound dressing, the system comprising: a sensor device according to any one of the first, second and third aspects for sensing and outputting the sensed data; and a remote device for receiving the output sensed data.

[0021] According to an eleventh aspect, there is provided a sensor device platform for placement in use, under a wound dressing, the sensor device platform comprising: at least one sensor connector for connecting in use, a sensor to the sensor device unit and for receiving sensed data from the connected sensor, an interface circuit electrically connected to die at least one sensor connector; an output for allowing access to the sensed data by an external entity a processor for processing the sensed data received from the sensor connector and providing the processed sensed data to the output; and a platform supporting each of the at least one sensor connector, the output and the interface circuit

BRIEF DESCRIPTION OF DRAWINGS

[0022] Embodiments of various aspects will be discussed with reference to the accompanying drawings wherein:

[0023 J Figure 1 - shows an embodiment of a first aspect of a sensor device;

[0024] Figure 2 - shows another embodiment of the sensor device of this first aspect with the output connected to a memory

[0025] Figure 3 - shows another embodiment of me sensor device of this first aspect with the output provided by a passive transmitter; [0026] Figure 4 - shows another embodiment of the sensor device of this first aspect with the output provided by an active transmitter;

[0027] Figure 5 - shows another embodiment of the sensor device of this first aspect with an interface circuit;

[0028] Figure 6A - shows another embodiment of the sensor device of this first aspect with a flexible pathway;

[0029] Figure 6B - shows another embodiment of the sensor device of this first aspect with the flexible pathway prwided by a flexible conductive wire;

[0030] Figure 6C - shows another embodiment of the sensor device of this first aspect with the sensor on a flexible substrate;

[0031] Figure 6D - shows another embodiment of the sensor device of this first aspect with the interface circuit on a flexible substrate;

[0032] Figure 6E - shows another embodiment of the sensor device of this first aspect with the output on a flexible substrate;

[00331 Figure 6F - shows another embodiment of the sensor device of this first aspect with the entire sensor device on a flexible substrate;

[0034] Figure 7A - shows another embodiment of the sensor device of this first aspect with two sensors;

[0035] Figure 7B - shows another embodiment of the sensor device of this first aspect with three sensors;

[0036] Figure 7C - shows another embodiment of the sensor device of this first aspect with four sensors;

[0037] Figure 7D - shows another embodiment of the sensor device of this first aspect with further sensors;

[0038] Figure 8 - shows an embodiment of the sensor device of a second aspect including an active transmitter;

[0039] Figure 9— shows another embodiment of the sensor device of this second aspect with an interface circuit;

[0040] Figure 1 OA - shows another embodiment of the sensor device of this second aspect with a flexible pathway; (0041 j Figure 1 OB - shows another embodiment of the sensor device of this second aspect with the flexible pathway provided by a flexible conductive wire

[0042] Figure IOC - shows another embodirnent of the sensor device of this second aspect with die sensor on a flexible substrate;

[0043] Figure 10D - shows another embodiment of the sensor device of this second aspect with the interface circuit on a flexible substrate

[0044] Figure 1 OE - shows another embodiment of the sensor device of this second aspect with the active transmitter on a flexible substrate;

[0045] Figure 1 OF - shows another embodiment of the sensor device of this second aspect with the entire sensor device on a flexible substrate;

[0046] Figure 11 A - shows another embodiment of the sensor device of this second aspect with two sensors;

[0047] Figure 1 IB - shows another embodiment of the sensor device of this second aspect with three sensors;

[0048} Figure 11 C - shows another embodiment of the sensor device of this second aspect with four sensors;

[0049] Figure 1 ID - shows another embodiment of the sensor device of this second aspect with fu her sensors;

[0050] Figure 12 - shows an embodiment of the sensor device of a third aspect including a pressure sensor;

[0051] Figure 13 - Shows another embodiment of the sensor device of this third aspect including a memory;

[0052] Figure 14 - shows an embodiment of the sensor device of this third aspect including a passive transmitter;

[0053] Figure 15 - shows an embodiment of the sensor device of this third aspect including an active transmitter,

[0054] Figure 16 - shows an embodiment of the sensor device of this third aspect including an interface circuit;

[0055] Figure 17A - shows an embodiment of the sensor device of this third aspect including a pressure sensor and a second sensor; (0056) Figure 17B - shows an embodiment of the sensor device of this third aspect including a pressure sensor and a third sensor;

[0057] Figure 17C - shows an embodiment of the sensor device of this third aspect including a pressure sensor and a fourth sensor;

[0058] Figure 17D - shows an embodiment of the sensor device of this third aspect including a pressure sensor and further sensors;

[0059] Figure 18 - shows a block diagram of a more detailed embodiment of one aspect of the system including the sensor device and the remote device;

[00601 Figure 19 - shows a plot of the transfer function for a temperature sensor for use in one embodiment;

[0061] Figure 20 - shows an interface circuit for the LM94021 temperature sensor used in one embodiment;

[0062] Figure 21 - shows the placement of moisture sensors on a mannequin leg in calibrating the moisture sensors;

[0063] Figure 22 - shows the output of the moisture sensors used in one embodiment;

[0064] Figure 23— shows a plot of the variation in characteristic impedance and output voltage of one of the moisture sensors used in one embodiment;

[0065] Figure 24 - shows an interface circuit for the HIH4030 moisture sensor used in one embodiment;

[0066] Figure 25 - Shows an interface circuit for the HCZD5 moisture sensor used in one embodiment;

[0067] Figure 26 - shows the result of measurement of the moisture content of a wound dressing at different stages in time after adding moisture to the dressing;

[0068] Figure 27 - shows a plot of die transfer function of a pressure sensor used in one embodiment, over a range of 0 to 40 mmHg of pressure;

[0069] Figure 28 - shows an interface circuit for the FSR402 pressure sensor used in one embodiment;

[0070] Figure 29 - shows an interface circuit for the FSR406 pressure sensor used in another embodiment;

[0071 j Figure 30A - shows one implementation ble substrate; [0072] Figure 30B - shows a rear view of the sensing system of die embodiment of Figure 30A ;

[0073 J Figure 31 A - shows a high level flowchart of the operation of the active wireless transmitter of the embodiment of Figure 18;

[0074] Figure 3 IB - shows a high level flowchart of the operation of a corresponding remote transceiver of a remote device for use with the arrangement of Figure 18;

[0075] Figure 32 - shows an example of a display screen of a remote device used in one embodiment;

10076] Figure 33 A - shows another example of a display screen with a custom graphical user interlace (GUI) for displaying output data from the wound sensor,

[0077] Figure 33B - shows another example of a display screen on a smart phone with an App for displaying output data from the wound sensor,

[0078] Figure 33C - shows another example of a display screen on a smart phone with an App for displaying output data from the wound sensor,

[0079] Figure 33D - shows another example of a display screen on a smart phone with an App for displaying output data from the wound sensor,

[0080] Figure 34A - shows an arrangement of the sensor device on a mannequin leg in one embodiment;

[0081 ] Figure 34B - shows the arrangement of Figure 34A covered with a wound dressing;

[0082] Figure 35A - shows a wound dressing arrangement for use in another experiment;

[0083] Figure 35B - shows an arrangement of the sensor device in this experiment, part of which is under the wound dressing of Figure 35A ;

[0084] Figure 35C - shows the sensor device of Figure 35B covered by a wound dressing, being a compression bandage in this embodiment;

[0085] Figure 3SD - shows a plot of various measurements obtained from the sensor device of Figure 35B;

[0086] Figure 36A - shows an arrangement of die sensor device in another experiment;

[0087] Figure 36B - shows the location of the p [0088] Figure 36C- shows the sensor device of Figure 36A under a compression bandage;

[0089 J Figure 36D - shows a plot of various measurements obtained from the sensor device of Figure 36A;

[0090] Figure 37 - shows a plot of various measurements obtained from another experiment;

[00 1 J Figure 38 - shows a plot of various measurements obtained from yet another experiment;

[0092] Figure 39 A - shows a plot of various measurements obtained from yet another experiment using a 4- layer wound dressing

[0093] Figure 39B - shows a plot of various measurements obtained from the experiment of Figure 39 A using a 2-layer wound dressing;

[0094] Figure 40 - shows a plot of moisture measurements over time as fluid drains from the moisture sensor in one experimental set up;

[0095] Figure 41 - shows a plot of temperature measurements over time as measured in another experimental setup;

[0096] Figure 42 - shows a sensor device platform according to another embodiment;

[0097] Figure 43 - shows the sensor device platform of Figure 42 flexed between a person's fingers;

[0098 J Figure 44 - shows a sensor device being the sensor device platform of Figures 42 and 43 with four sensors connected thereto;

[0099] Figure 45A - is a circuit diagram of the elements of the sensor device of Figure 44;

[00100] Figure 45B - shows a circuit track layout on the flexible PCB/platfor of Figure 42;

[00101] Figure 46A - is a graph showing the relationship between pressure applied to a pressure sensor used in the sensor device of Figure 44 and the output voltage of the pressure sensor;

[00102] Figure 46B - is a graph showing the relationship between the value of moisture sensed by a moisture sensor used in the sensor device of Figure 44 and the output vol tage of the moisture sensor;

[00103] Figure 47 - shows the relationship between measured pressure value as battery voltage drops over time; ( (H) 104] Figure 48A - shows a graph of measures pressure values vs battery voltage without using any compensation for battery voltage drop;

[00105] Figure 48B - shows the graph of Figure 48A using a 1⁴¹ degree polynomial for compensation;

[00106] Figure 48C - shows the graph of Figure 4 A using a 2^ftd degree polynomial for compensation;

[00107] Figure 48D - shows the graph of Figure 48 A using a Gaussian polynomial for compensation;

[00108] Figure 49A - shows a first stage of an experimental set up applied to a mannequin leg;

[00109] Figure 49B - shows a second stage of the experimental set up of Figure 49A;

[00110] Figure 49C - shows a third stage of the experimental set up of Figure 49 A;

[00111] Figure 50A - shows a graph of the pressure measurements taken m die experimental set up of

Figures 49A to 49C

[00112] Figure SOB - shows a graph of the moisture measurements taken in the experimental set up of

Figures 49A to 49C

[00113] Figure 51 A - shows a first stage of an experimental set up on a healthy volunteer,

[00114] Figure SIB - shows a second stage of the experimental set up of Figure 51 A;

[00115] Figure SIC - shows a third stage of the experimental set up of Figure 51 A;

[00116] Figure 52 A - shows a plot of the pressure measurements of die experimental set up of Figures

51 A to 51C using a 4-layer bandage, taken at the ankle;

[00117] Figure S2B - shows a plot of the pressure measurements of the experimental set up of Figures 51 A to SIC using a 4-layer bandage, taken at die calf;

[00118] Figure S3A - shows a plot of the pressure measurements of the experimental set up of Figures 51 A to 5 C using a 2-layer bandage, taken at the ankle;

[00119] Figure 53B - shows a plot of the pressure measurements of the experimental set up of Figures

51 A to 51C using a 2-layer bandage, taken at the calf; [00120] Figure 54A - shows an experimental set up to test moisture measurements;

| ^{( )}121 | Figure 54B - shows <he experimental set up of Figure 54A after fluid has been injected into the dressing;

[00122] Figure 35 - shows a plot of the moisture measurements measured in the experimental set up of

Figures 54A and 54B;

[00123] Figure 56 - shows one embodiment of a general sensor device with a control signal generator for generating a control signal;

[00124] Figure 57 - shows a specific embodiment of the sensor device with a control signal generator for generati ng a control signal of Figure 56;

[00125] Figure 58 - shows a general sensor device platform accordin to another aspect, for connecting to one or more sensors; and

[00126] Figure 59 - shows an embodiment of a sensor device platform.

DESCRIPTION OF EMBODIMENTS

[00127] Throughout this description and the claims, the term "wound dressing" is used. It will be understood that the term "wound dressing" is intended to include any covering that is applied over or about a wound as part of the treatment of the wound. This can include a dressing applied directly over the wound, such as gauze or other dressing. This can also include a bandage which can be applied either directly over the wound, or over a dressing already applied directly over the wound, to provide pressure, protection or secureraent over the already-applied dressing. A "wound dressing" as referred to in the present application can comprise a single dressing, or multiple separate dressings over or about the wound. When a sensor or sensor device is described or claimed as being placed under a wound dressing, it will be understood that this encompasses placement under all of the wound dressing (e.g. directly onto the skin of the patient), as well as encompass placement within a multi-layer wound dressing, such as over a gauze placed directly over the wound and under a bandage placed over the gauze, or between 2 or more layers of a bandage wound to form several layers.

[00128] Referring now to Figure 1 , there is shown an embodiment of a sensor device 100 according to one aspect. In this aspect, the sensor device 100 is flexible, to provide a flexible sensor device comprising at least one parameter sensor 11 for placement under a wound dressing in use and for sensing a parameter under the wound dressing and for generating sensed da 120 for allowing the sensed data to be retrieved while the at least one parameter sensor 110 remains under the wound dressing, as will be described fa more detail below.

[00129] Figure 1 shows the sensor device 100 with at least one sensor 110 and an output 120. In this embodiment, there is one sensor 110, which can be any type of sensor suitable for the required purposes. For example, in one embodiment, sensor 110 is a pressure sensor. In. another embodiment, sensor 11 is a temperature sensor. In another embodiment, sensor J 10 is a moisture sensor. In yet another embodiment, sensor 110 is a pH sensor. In yet another embodiment, sensor 110 is a bacterial sensor, in another embodiment, sensor 110 is a movement sensor such as an accelcrometer or a mercury switch. In another embodiment, sensor 110 is a gas sensor.

[00130] Output 120 is provided by any suitable means for allowing sensed data as sensed by sensor

110 to be provided to an external entity, in one embodiment, output 120 is a simple electrically conductive contact to allow an electrically conductive remote device such as an electrical meter, to contact the electrical contact and receive electrical readings directly from the sensor 110.

[00131] In another embodiment, output 120 is provided as a connector 120/140 connected to a memory 130. In this embodiment, sensed data provided by sensor 11 is stored in memory 130 for access by an external entity at a later time.

[00132] In another embodiment, as shown in Figure 3, output 120 is provided by a passive transmitter

120/150 for allowing sensed data to be accessed wirelessly when interrogated by an external party. In one embodiment, the passive transmitter 120 150 is an RF1D (Radio Frequency Identification) chip with one or mote inductive coils which can couple with corresponding one or more inductive coils in a remote device (not shown in this figure) when the remote device is brought sufficiently close to the passive transmitter as will be understood by the person skilled in the art

[00133] In another embodiment, as shown in Figure 4, output 120 is provided by an active transmitter 120/160. Any suitable active transmitter can be used, examples of which will be provided in more detail below. An active transmitter in this context will be able to transmit data at distances greater than about O.OSm. For example, about 0.05m to about 0.1m, about 0.1m to about 0.5m, about 0.5m to about 1m, about lm to about 2m, about 2m to about 3m, about 3m to about 4m, about 4m to about 5m, about 5m to about 10m, about 10m to about 20m, about 20m to about 50m and greater than about 50m.

[00134] In another embodiment, as shown in Figure 5, the sensor device 100 also comprises an interface circuit 170 disposed between the at least one sensor 110 and the output 120. Interface circuit 170 will be arranged to process the raw sensed data provided by sensor 1 1 into a form that can be processed by the output. In one embodiment, interface circuit 170 ert analogue data from the sensor 110 to a digital form for use by the output 120. in another embodiment, interface circuit 170 is a digital to analogue converter (DAC) to convert digital data generated by sensor 110 (if sensor 110 outputs digital data) for use by the output 120. In another embodiment, interface 170 provides noise cancellation or reduction, in another embodiment, interface circuit 170 provides amplification. In other embodiments, interface circuit 170 provides a combination of two or more of Ac above. Other examples will be provided in more detail further below.

[00135] It will be appreciated that while the interface circuit 170 is represented as a separate block to die sensor 11 and output 120 in Figure 5, interface circuit 170 need not be a separate block in all

embodiments. In some embodiments, the circuitry of interface circuit 170 is provided by circuitry supporting sensor 110. In other embodiments, interface circuit 170 is provided by circuitry supporting output 120. In some embodiments, the circuitry of interface circuit 170 is distributed between circuitry supporting sensor 110 and circuitry supporting output 120. In other embodiments still, the circuitry is provided by circuitry supporting sensor 110, circuitry supporting output 120 as well as separate circuitry disposed between sensor 110 and output 120.

[00136] As described above, in this aspect, sensor device 100 is flexible. It will be understood that the term "flexible" is intended to mean that the sensor device 1 0 is able to be deformed to substantially conform with the surface of a part of the patient on which the sensor device 1 0 is placed in use. For example, if the sensor device is placed on the patient's arm, the sensor device is able to bend with the curvature of die arm to allow the sensor device 100 to lie against the arm. In some embodiments, the sensor device 100 will require constant pressure (for example from a wound dressing applied over it) to keep it in a flexed state. In this embodiment, the sensor device 100 will return to an unflexcd state when the pressure (e.g. from a wound dressing) is removed. In other embodiments, sensor device 1 0 will be able to be flexed to a desired state and it will remain in this state until energy is applied to return it to an unflexcd state.

[00137] In one embodiment, as shown in Figure 6A, sensor device 100 is made flexible by virtue of at least a portion of a pathway 117 between sensor i 10 and output 120 being flexible. In one embodiment of this arrangement, the flexible pathway 117 is provided by an electrically conductive flexible wire 117/1 IS as shown in Figure 6B.

[00138] In another embodiment, as shown in Figure 6C, the flexibility of the sensor device 100 is provided by sensor 110 being on a flexible substrate 116. m another embodiment, as shown in Figure 6D, the flexibility of the sensor device 100 is provided by interface circuit 170 being on a flexible substrate 116. In another embodiment, as shown in Figure 6E, the flexibility of the sensor device 100 is provided by output 120 being on a flexible substrate 116. In another embodiment, as shown in Figure 6F, the flexibility of the sensor device 1 0 is provided by each of the sensor 110 exible substrate 116. In another embodiment, any two of the sensor 110, interface circuit and output are provided on a flexible substrate 116.

[00139] in other embodiments, as shown in Figure 7 A, sensor device 100 comprises two sensors 10 and 111. In other embodiments, sensor device 100 comprises three sensors 110, 11 and 112 as shown in Figure 7B. In other embodiments, as shown in Figure 7C, sensor device 100 comprises four sensors 110, 1, 112 and 1 3. In other embodiments, as shown in Figure 7D, sensor device 100 comprises at least one further sensor 114. In some embodiments then, sensor device 100 will have 1 , 2, 3, 4, 5, , 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18, 9, 20, 20 to 30, 30 to 40, 40 to 50 or more than 50 sensors.

[00140] In one embodiment, each sensor 110, 111 etc. senses its own parameter. Parameters sensed by the sensors include temperature, pressure, moisture, pH and bacterial count Other parameters that may be deemed to e useful can also be sensed by an appropriate sensor, for example, sensing a particular gas emanating from the wound.

[00141] In one embodiment, sensor 110 is a temperature sensor. In another embodiment, sensor 110 is a pressure sensor. In another embodiment, sensor 110 is a moisture sensor, fo another embodiment, sensor 110 is a pH sensor. In another embodiment, sensor 110 is a bacterial sensor.

[00142] In other embodiments, in which sensor device 100 has two sensors 110 and 111, in one embodiment, sensor 110 is a temperature sensor and sensor 1.11 is also a temperature sensor. In such embodiments, one sensor 110 may be used to sense temperature at or near a wound under the wound dressing and the other sensor 111 may be located further away from the wound to act as a reference temperature sensor.

[00143] In other embodiments with two sensors, sensor 11 is a temperature sensor and sensor 111 is a pressure sensor. In other embodiments, sensor 110 is a moisture sensor and sensor 111 is a pH sensor.

[00144] Thus, it can be seen that with two sensors and five possible parameters (for example), there are

25 possible combinations. To generalise, with two sensors and P possible parameters, there arc P² possible combinations.

[00145] In other embodiments in which there arc three sensors, again, two or more sensors may sense the same parameter, or each sensor may sense a different parameter, or any combination of this. Thus, with three sensors and five possible parameters, there are 125 possible combinations. To generalise, with P possible parameters, there arc P³ possible combinations.

[00146] In other embodiments in which there are four sensors, again, two or more sensors may sense the same parameter, or each sensor may sense a d hus, with four sensors and five possible parameters, there arc 625 possible combinations. To generalise, with P possible parameters, there are P⁴ possible combinations.

[00147] in a general embodiment in which there ate S sensors and P parameters, there are P^s possible combinations.

[00148] According to another aspect, the output 120 is provided by an active transmitter 120/1 0. In this aspect, there is provided sensor device 100 comprising at least one parameter sensor 110 for placement under a wound dressing in use and for sensing a parameter under the wound dressing and generating sensed data relating to the sensed parameter; and an active wireless transmitter 120/160 for receiving data from the at least one parameter sensor .110 and for transmitting the sensed data to a remote device 200.

[00149] n this aspect, the sensor device 1 0 need not be flexible in ail embodiments. Figure 8 shows sensor device 100 with sensor 110 for sensing a parameter under a wound dressing, the sensor 110 connected to active transmitter 120/160. Active transmitter 120/160 is able to transmit data received from sensor 110 wirelessly to a remote device 200. Active transmitter 120/160 can be any suitable active transmitter as will be described in more detail below.

[001 SO] Tt will also be appreciated that in some embodiments, active transmitter 120/160 is a transceiver, also having receiver capabilities. In these embodiments, transceiver 120/160 is able to receive data such as commands, f om remote device 200.

[00151] As shown in Figure ?_« in another embodiment, sensor device 100 further comprises a circuit interface 170 as previously described.

[00152] In some other embodiments of this aspect, sensor device 100 is flexible, with the flexibility provided by a number of possible means as previously described. In particular, as shown in Figure 10A, the flexibility is provided by a portion of the pathway 1 17 between sensor 110 and active transmitter 120/160 being flexible, such as an electrically conductive flexible wire 117/115 as shown in Figure 10B. In other embodiments, the flexibility is provided by the sensor 110 being on a flexible substrate 116 such as shown in Figure IOC, or the circuit interface 170 being provided on a flexible substrate 116 as shown in Figure 10D, or the active transmitter 120/160 being provided on a flexible substrate 116 as shown in Figure 10E. Any combination of these is also possible , as is an embodiment in which all of the sensor 110, interface circuit 170 and active transmitter 120/1 0 being provided on flexible substrate 116, as shown in Figure 1 F.

[00153] In other embodiments of this aspect, mere are provided two sensors 110 and 111 with respective interface circuits 170 and 171 connecting the sensors to active transmitter 120 160 as shown in Figure 11 A. In other embodiments, sensor device ith corresponding interface circuits 170, 171 and 172 as shown in Figure 1 IB. In other embodiments, sensor device 100 comprises four sensors 110, 111, 112 and 113 with corresponding interface circuits 170, 171, 172 and 173 as shown in Figure 11 C. Tn other embodiments, sensor device 0 comprises at least one further sensor 114 with corresponding interface circuit 174 as shown in Figure 1 I^'D. In some embodiments then, sensor device 100 will have 1, 2, 3, , 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 20 to 30, 30 to 40, 40 to 50 or more than 50 sensors, each with their corresponding interface circuit

[00154] In one embodiment, each sensor 110, 111 etc. senses its own parameter. Parameters sensed by the sensors include temperature, pressure, moisture, pH and bacterial count. Other parameters that may be deemed to be useful can also be sensed by an appropriate sensor.

[00155] In one embodiment, sensor 1 10 is a temperature sensor. In another embodiment, sensor 1.10 is a pressure sensor. In another embodiment, sensor 110 is a moisture sensor. In another embodiment, sensor 110 is a pH sensor. In another embodiment, sensor 110 is a bacterial sensor.

[00156] In other embodiments, in which sensor device 100 has two sensors 110 and 111, in one embodiment, sensor 110 is a temperature sensor and sensor 111 is also a temperature sensor. In such embodiments, one sensor 11 may be used to sense temperature at or near a wound under the wound dressing and the other sensor 111 may be located further away from the wound to act as a reference temperature sensor.

[00157] In other embodiments, there can also be two pressure sensors, where one sensor is used to sense pressure at or near the wound under the wound dressing, and the other sensor may be located further away from the wound, either under the wound dressing or under no wound dressing, to act as a reference pressure sensor,

[00158] In other embodiments with two sensors, sensor 110 is a temperature sensor and sensor 111 is a pressure sensor. In other embodiments, sensor 110 is a moisture sensor and sensor 111 is a pH sensor.

[001 9] Thus, it can be seen that with two sensors and five possible parameters (for example), there are 25 possible combinations. To generalise, with two sensors and P possible parameters, there are P² possible combinations.

[00160] In other embodiments in which there are three sensors, again, two or more sensors may sense the same parameter, or each sensor may sense a different parameter, or any combination of this. Thus, with three sensors and five possible parameters, there are 125 possible combinations. To generalise, with P possible parameters, mere are P¹ possible combinations. [00161] In other embodiments in which there are four sensors, again, two or more sensors may sense the same parameter, or each sensor may sense a different parameter, or any combination of this. Thus, with four sensors and five possible parameters, there arc 625 possible combinations. To generalise, with P possible parameters, there are P⁴ possible combinations.

[00162] In a general embodiment in which there are S sensors and P parameters, there are P^s possible combinations.

[00163] In a further aspect, as shown in Figure 12, sensor device 100 comprises at least one pressure sensor 11 and an output 120. There is thus provided a sensor device 1 0 comprising at least one pressure sensor 110 for placement under a wound dressing in use and for sensing pressure under the wound dressing and generating sensed data; and an output 1.20 for allowing the sensed data to be retrieved while the at least one parameter sensor 11 remains under the wound dressing.

[00164] In one embodiment, output 120 is an electrical connector 120 140 connected to a memory

120/140 for accessing sensed data stored by memory 120/140 as shown in Figure 13. In another embodiment, output 120 is a passive wireless transmitter 120/1 0 as shown in Figure 14 and in another embodiment, output 120 is an active transmitter 120/160 or transceiver. Jn this aspect, sensor device 100 need not be flexible in some embodiments.

[00165] In some embodiments as shown in Figure 16, sensor device 100 further comprises interface circuit 170 as previously described.

[00166] In some embodiments of this aspect, sensor device 100 is flexible, with the flexibility provided by a number of possible means as previously described. In particular, in one embodiment the flexibility is provided by a portion of the pathway 11 between sensor 110 and active transmitter 120/160 being flexible, such as an electrically conductive flexible wire 114/11 . In other embodiments, the flexibility is provided by die sensor 110 being on a flexible substrate 116, or the circuit interface 170 being provided on a flexible substrate 116, or the active transmitter 120/160 being provided on a flexible substrate 116. Any combination of these is also possible, as is an embodiment in which all of the sensor 110, interface circuit 170 and active transmitter 120/160 being provided on flexible substrate 116.

[00167] In other embodiments of this aspect, mere arc provided two sensors 110 and 111 with respective interface circuits 170 and 171 connecting the sensors to active transmitter 120/1 0 as shown in Figure 17A. In other embodiments, sensor device 100 comprises three sensors 110, 111 and 112 with corresponding interface circuits 170, 171 and 172 as shown in Figure 17B. In other embodiments, sensor device 1 0 comprises four sensors 11.0, 11 1, 112 and 113 with corresponding interface circuits 170, 171 , 172 and 173 as shown in Figure 17C. In other embod further sensor 114 with corresponding interface circuit 174 as shown in Figure 17D. In some embodiments then, sensor device 100 will have 1, 2, 3, 4, 5, 6, 7, 8, , 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 20 to 30, 30 to 40, 40 to 50 or more than 50 sensors.

[00168] In one embodiment, each sensor 110, 111 etc. senses its own parameter. Parameters sensed by the sensors include temperature, pressure, moisture, pH and bacterial count Other parameters that may be deemed to be useful can also be sensed by an appropriate sensor.

[00169] In one embodiment, sensor 110 is a temperature sensor. In another embodiment, sensor 1 0 is a pressure sensor. In another embodiment, sensor 110 is a moisture sensor. In another embodiment, sensor 110 is a pH sensor. In another embodiment, sensor 110 is a bacterial sensor.

[00170] In other embodiments, in which sensor device 1 0 has two sensors 110 and 111, in one embodiment, sensor 110 is a temperature sensor and sensor 111 is also a temperature sensor. In such embodiments, one sensor 110 may be used to sense temperature at or near a wound under the wound dressing and the other sensor 11 J may be located further away from the wound to act as a reference temperature sensor.

[00171] In other embodiments with two sensors, sensor 110 is a temperature sensor and sensor 111 is a pressure sensor. In other embodiments, sensor 1 10 is a moisture sensor and sensor 111 is a pH sensor.

[00172] Thus, it can be seen that with two sensors and five possible parameters (for example), there are

25 possible combinations. To generalise, with two sensors and P possible parameters, there are P² possible combinations.

[00173] In other embodiments in which there are three sensors, again, two or more sensors may sense the same parameter, or each sensor may sense a different parameter, or any combination of this. Thus, with three sensors and five possible parameters, there are 125 possible combinations. To generalise, with P possible parameters, there are P³ possible combinations.

[00174] In other embodiments in which there arc four sensors, again, two or more sensors may sense the same parameter, or each sensor may sense a different parameter, or any combination of this. Thus, with four sensors and five possible parameters, there are 625 possible combinations. To generalise, with P possible parameters, mere are P⁴ possible combinations.

[00175] lh a general embodiment in which there arc S sensors and P parameters, there arc P^s possible combinations. [00176] A specific embodiment will now be described in detail. In this embodiment, there is provided a flexible wireless telemetric system that can provide continuous sensing and monitoring of the wound environment underneath a wound dressing.

[00177] According to one aspect, there is provided a system 500 for obtaining sensed data of one or more parameters relating to a region under a wound dressing, the system comprising; a sensor device 100 as described herein for sensing and outputting the sensed data; and a remote device for receiving the output sensed data.

[00178] In one embodiment, as shown in Figure 18, the sensor device 100 is capable of measuring and transmitting real-time information on temperature, moisture, and bandage or dressing pressure from within the wound dressing and with programmable transmission intervals. The wireless sensing system is fabricated on a flexible printed circuit material, while the sensors arc micro-sized and flexible, thus making the system minimally invasive to wounds and the human body. The receiver is portable with the capability to receive data accurately within a distance of 4-5 meters.

[00179] The sensor device 100 can be powered by any suitable means including by battery, inductive power or self-power, for example by energy generated through movement of the patient.

[00180] The sensors 110, 111, U 2 and 113 (temperature, moisture (2 moisture sensors) and pressure), have a flexible physical structure. Custom interface circuits 170 (described in more detail below) are designed to connect these sensors to active transmitter 120/160. An in-built J 0-bit analog to digital converter (ADC) 170a is used for signal conversion from analog to digital It will be appreciated mat in this embodiment, ADC 170a provides a part of the interface circuitry 170 to provide a distributed interface circuitry as previously described.

[00181] Active transmitter 120/160 uses, in mis embodiment, the IEEE 804.15.4 ZigBee* protocol for data transmission. The sensors' digital data is stored in the internal buffer of active transmitter 120/160 and is then transmitted over the air channel 400 to the remote device 200 through a miniature matched RF antenna 120/162. The remote device 200 is designed with exactly matching characteristics with those of the active transmitter 120/160. In this embodiment, there is a remote antenna 210, remote device impedance matching network 220, remote device transceiver 230, signal processing block 240 and remote device display 250, on which information relating to the sensed data can be displayed to a user.

[00182] It will be appreciated that an suitable form of wireless communications protocols or systems can be used. Such systems or protocols include ZigBee* (IEEE 802.15.4), Bluetooth* (IEEE 802.15.1-xxxx), Bluetooth* Low Energy (BLE), WirFi* (IEEE 802 1 Ixx) RFID (active passive semi active) and ISM (Industrial, Scientific and Medical) RF bands wit [00183] Temperature sensor 110, in this embodiment, is an L 94021B temperature sensor provided by

Texas Instruments Inc. This ultra-low power sensor typically consumes about 9 uA current at a rated 5V supply voltage. This sensor has a size of 2.15 mm x 2.40 nun x 1.1 mm (Lx W x H) and a nominal accuracy of ±1.5 °C in the temperature range 20-40 *C.

[00184] Pins GS1 :GS0 of the sensor are tied to logic 1. to obtain the highest gain of 13.6mV/* I

[00185] Using the transfer table from the sensor's datasheet and a MATLAB curve-fitting tool, the following mathematical relationship is derived between the temperature (T) and the sensor's output voltage (Vout).

[00186] The transfer function above is linear, with a 5V supply voltage, as shown in Figure 19. The temperature sensor 110 is calibrated over the 20-50 °C range using a Digitech QM 153 multimeter. Figure 20 shows one embodiment of an interface circuit (in this case, a simple voltage divider) connected to the output pin of the LM 4021 temperature sensor.

[00187] With reference to title moisture sensors 111 and 112, moisture sensing comes in two modes: active or passive. Active sensing requires an external voltage or current signal to the piezoelectric sensor for its operation, while passive sensing is performed without any external excitation signal and by sensing the change in impedance (piezo-resistive), capacitance (piezo-capacitive) or inductance (piezo-inductive) between die two electrodes of the sensor, hi mis embodiment, the moisture sensors 111 and 112 were selected as an HIH4030 piezoelectric moisture sensor provided by Honeywell International Inc and an HCZ-D5 piezo- rcsistivc moisture sensor provided by Element 14 (previously Premier Farncll pic) under die brand name Multicom . The H1H4030 has dimensions of 8.59mm x 4,2mm x 3.5mm (L x x H) and operates at 5V supply voltage. Its measurement range is 0 - 100 %RH with normal accuracy of +- 3.5 %RH. Typical current consumption of this sensor is 200 μΑ.

[00188] For calibration and characterization, two moisture sensors were used with one acting as a reference. These sensors were placed on opposite sides of a mannequin leg, as shown in Figure 21, and then covered with a wound dressing, in this example, a commercial pressure bandage sold under the trade mark AMS Bi-FIex*, which was wrapped around the leg. Both sensors were powered using a 5 V supply, and their output data was sampled at 100 mHz using National Instruments data acquisition card NI DAQ 6009.

[00189] After about 30 seconds, distilled water was sprayed near the wound dressing above the second moisture sensor. This experiment was conducted was plotted, as shown in Figure 22. [00190] The following equations were used to calculate the moisture level at any temperature:

[001 ¾> 11 A passive resistive moisture sensor operates without any excitation signal and produces a change in resistance or impedance between its terminals in response to a change in moisture,

[00192] The HCZ-D5 sensor selected in this example has a size of 10 mm x 5 mm x 0.5 mm (L xWx H). The rated accurac of this sensor is ± 5 %RH.

[00193] In mis embodiment, the HCZ-D5 sensor is used as a variable moisture-sensitive resistor in a differential amplifier circuit. This circuit uses an LM 58 operational amplifier IC. The sensor's data sheet provides the value of its resistance as a function of moisture level (20-90 %RH) for the temperature range 5- 60°C. These resistance values are used with the following equation obtained through circuit analysis as would be understood by the person skilled in the art, to determine the output voltage expression for the interface circuit.

where M is the resistance between the positive input terminal of the LM358 and ground; R_um is the variable resistance of the HCZ-D5 sensor; and

V» is the supply voltage.

[00194] The val ues of and V_ow are plotted against the moisture level for a selected temperature range of 25-40°C, as shown in Figure 23.

[00195] An interface circuit 171 is also designed to properly operate the moisture sensor. Using the sensor's datasheet and the ATLAB curve fitting tool the following mathematical expression is derived between the moisture levels ( ) in RH and the

where

/ p and,

[00196] Figure 24 shows an example of an interface circuit for use with the HIH4030 moisture sensor described above, while Figure 25 shows an example of an interface circuit for use with the HCZ-D5 moisture sensor described above.

[00197] Figure 26 shows die result of measurement of the moisture content at different stages in time after adding moisture to the dressing,

[00198] In relation to the pressure sensor, again, any type of sensor suitable for the purpose can be used. In one embodiment, the FSR series of flexible force sensors provided by Interlink Electronics, Inc is used. One example is the FSR402 sensor with a size of 13mm diameter and a 56mm long stem.

[00199] To determine the transfer function of the FSR402 pressure sensor, the sensor was placed on a mannequin leg with a commercial pneumatic pressure meter (HPM-KH-01) for validation of pressure measurements. The wound dressing ( being a pressure bandage in (his case) was wrapped around the leg and pressure readings were taken from the pneumatic meter, while measuring the output voltage of the FSR402 sensor for pressure values ranging from 1 to 40 mmHg in ImmHg intervals.

[00200] The data acquired from this process was plotted (see Figure 27) and the followin empirical relation was obtained using the MATLAB curve fitting tool:

where:

* and

and die voltage is expressed in mV.

10020 I f Figure 28 shows an example of an interface circuit for the FSR402 pressure sensor used in the embodiment described above.

[00202] In another embodiment, pressure sensor 113 can be provided by piczo-resistive pressure sensor

FSR406, also provided by Interlink Electronics, Inc. This sensor has a square sensing area of 38mm x 38mm and is non-invasive, flexible and 0.5mm thick. The pressure sensor 113 is calibrated using a clinical -grade pressure meter ikuhime HPM-KH-01 , for valid ti f t t 40 H which is regarded as high bandage pressure. An interface e sensor. [00203] A commercial stretchable pressure wound dressing (Cobpn ) is used to create pressure over the sensor 113, Using the MATLAB curve-fitting tool, the following mathematical expression is derived between the pressure (P) in mrtiHg and the output voltage (V,*) in mV.

where, *

[00204] Figure 29 shows an example of an interface circuit for the FSR406 pressure sensor used in the embodiment described above.

[00205] In this embodiment, the active transmitter 120/160 has an on-chip 10-bit ADC 120/170a for converting external analogue signals applied to the chip to a digital format.

[00206] The active transmitter 120/160 is selected as an ATMegal 28RFA I RF transceiver, provided by Atmel Corporation. The transceiver is of small size (9 mm x 9 mm x 1 mm) and operates at 2.45GHz ISM (industrial, scientific, medical) frequency band using IEEE 802.15.4 ZigBee* protocol. It has -100 dBm sensitivity and a 3.5 dBm programmable output power. It also contains a programmable serial interlace and a 10-bit analog-to-digital (ADC) converter.

[00207] The sensor device 100 is designed and fabricated on a 0.15mm 2-layer flexible printed circuit board as shown in Figure 30A. To protect the delicate components from being damaged by the bandage or wound dressing pressure, transparent insulating silicon is coated over the circuit components. In other embodiments, a flexible, protective casing may be provided to protect the components and facilitate placement of the sensor device on the patient

[00208] Figure 30B shows the reverse side of the sensing system of the arrangement of Figure 30A.

[00209] The sensors 110, 111, 112 and 113 are connected to port F (ADC input port) of the transceiver through the customised interface circuits 170. A Bahin device (such as P/N 2450FB15L0001 provided by Johanson Technology, Inc) and a 2.4GHz chip antenna (such as P/N 2350AT43B100 from Johanson

Technology, Inc) are used in this embodiment. The same components are used on the remote device 200.

[00210] A firmware program was designed in C++ and implemented in the transceiver devices of bom the sensor device 100 and the remote device 200, using Atmel Corporation's AV Studio 6.0 software tool.

10021 I f In operation, the information captured by the sensors 110, 111, 112 and 113 is first converted into digital format and then stored in the TX fram buffer register is written with frame length information followed by the sensed data. Before transmitting, the transmitter is passed through a set of pre-defined states, i.e.

[00212] After transmitting one packet of information, the active transmitter 120/160 is turned off

(TRX OFF) to conserve battery energy.

[00213] The complete operation of the active wireless transmitter TX J 20/160 and the remote device receiver RX 230 is shown in high level flowcharts as shown in Figures 31 A and 31 B respectively.

[00214] An example of pseudo code for one method of carrying out these steps for the transmitter is:

Program Starts:

Include required libraries

Define frame buffer into available memor space

Define variables for data storage

Tl, T2 Ml, M2, Pl, P2 etc.

Define PORT F direction

PORT F must be declared as input port

Disable digital input buffer on ADC port

Define transceiver state

Clear all pending interrupts

Enable transceiver (TRX) interrupts

RESET transceiver and all of its registers

Wait for transceiver to awake from SLEEP state

Bring the transceiver back into TRX OFF state

Re-insert TRX OFF state

RESET transceiver power register (TRXPR)

Set transmitter output power (e.g. 0 dBm)

Set frequency channel from the available band (2405-2480 MHz)

Set data rate

Set start of frame delimiter (SFD) value

Forever loop

Define frame length i.e. number of bytes to be transmitted

Store transmitter device ID into frame buffer

Initialize analog to digital converter (ADC)

Set clock pre-scalar to division by 8

Set ADC track-and-hold and start-up times

Select internal 1.8 V reference voltage

Select to left shift the result

Select first analog input to digitize

Start ADC arid convert analog to digital

Enable ADC operation

Wait for 600 micro seconds

Start conversion (ADC operation starts)

Wait for ADC to compl t i

Get ADC result Store first ADC result into frame buffer

Select second analog input to digitize

Start ADC and convert to digital

Store second ADC result into frame buffer

Select subsequent analog inputs, convert to digital, and store into frame buffer Insert desired delay in milliseconds (e.g. 20000 ms = 20 s)

Start transmission

Set the transceiver state to TRANSMIT (TRX or PLL ON)

Wait for phase-lock-loop (PLL) to lock at selected transmit frequency

Set transmitter to START state (TX START)

Stop transmission

Wait for frame transmission end signal

Return to previous TRX state ie. TRX OFF

Loop ends

Program ends

Some pscudo code for one method of carrying out these steps for the receiver is:

Program Starts:

Include standard libraries

Include t6963c.k and graphics.h libraries

Define frame buffer into available memory space

Define variables for data storage

dataJTl , data_T2, data_M 1, data_M2, data_Pl , data_P2 etc.

Define transceiver state

Clear all pending interrupts

Enable transceiver (TRX) interrupts

RESET transceiver and all of its registers

Wait for transceiver to awake from SLEEP state

Bring the transceiver back into TRX OFF state

Re-insert TRX OFF states

RESET transceiver power register (TRXPR)

Set transmitter output power (e.g. 0 dBm)

Set frequency channel from the available band (2405-2480 MHz)

Set data rate

Set start of frame delimiter (SFD) value

Set receiver slate

Set transceiver to PLL ON state

Wait for PLL to lock at selected receive frequency

Set transceiver to RECEIVE (RX__ON) state

initialize LCD

Clear text area

Clear character generator area

Clear graphics area

Forever loop

Wait for complete reception of a packet

Read receive frame buffer register

Store data in variables

Perform calctdations on stored data

Calculate received ener

Calculate temperature u Calculate moisture using transfer function

Calculate pressure using transfer function

Send calculated values to LCD

Display parameters on LCD

Loop ends

Program ends

[00216] The net weight of the sensor device 100 of mis embodiment is !.938g without the sensors 110,

111, 112 and 113, and 6.70 g with all the sensors attached, and 9,74g with the sensors and an alkaline battery, having dimensions of 14mm x 10mm. The nominal and maximum current consumptions of the sensor device 100 of this embodiment are measured as 13.58mA and 17.4mA respectively. The peak power consumption is therefore 57,4mW at 3.3V supply voltage.

[00217] In one embodiment, the dimensions of the sensor device 1 0 are about 47mm x about 29mm. in another embodiment, the dimensions are about 97mm x about 32mm.

[00218] In this embodiment, the transmitter chip has an on-chip 10-bit ADC for converting any external analog signal into digital. The result of this ADC conversion is stored in two 8-bit registers; ADCH for high byte and ADCL for low byte. The maximum reference voltage fo the ADC is 1.8V, which is internally generated and stabilized. All the sensors in mis embodiment work at a 5V supply and their output voltage may rise above 1.8V which means mat the ADC would essentially be saturated and would provide 0XFF for all input values exceeding its reference voltage. Accordingly, this arrangement would not be able to detec any input signal above 1.8V. This problem is resolved by reducing the ADC input voltage range such that the maximum input voltage of any sensor is less man the ADC reference voltage. For this purpose, a simple voltage divider circuit is designed using two surface mount resistors R i and R. for each sensor.

[00219] The voltage divider circuit necessitates proper impedance matching with the sensors. The temperature sensor LM94021 consumes almost 9 uA current at 5V, resulting in an impedance of nearly 555 k£l In order to safely reduce the output voltage, a 750 ki standard value for both resistances are selected, providing a voltage division ratio of two. The active moisture sensor H1H4030 operates at 5V, consuming almost 200 uA of current, thus producing an input impedance of 25 kO. For this sensor, Rx = 46 \£l and R₂ = 25 kQ, resulting in a voltage division ratio of 2.84. Using the same principle for the pressure sensor FSR406, the resistance values are chosen as Ri = 56.2 kQ and Rj = 46.4 kil, resulting in a voltage division ratio of 2.21. For the passive moisture sensor HCZ-D5, the values of R_t and R₂ are 46 kQ and 25 kQ respectively. The values of Ri and R₂ may be adjusred to any other values provided mat they generate the same division ratio and their combined effect docs not overrule the impedance matching criteria.

[00220] The transmitted data in ZigBee* 802 15 4 protocol is received by the remote device 200, in mis case a handheld receiver, processed by T696 cm LCD screen as shown in Figure 32. As can be seen in Figure 32, the screen shows, for a particular sensor device (in this example indicated as device ID 31), the channel frequency, and real-time values of temperature, moisture and pressure. In other embodiments, other information can be displayed as required for the particular application. For example, where the sensor device 200 includes two sensors for temperature, the display screen can display a reference temperature and the temperature under (he wound dressing. In other embodiments where sensors are provided to sense other parameters, one or more of those other parameters can also be displayed.

[00221] In another embodiment, the display can be provided on a computer screen with a custom graphical user interface as shown in Figure 33A. This display shows real-time plots of the various parameters as they change over time, as well as tile data values.

[00222] In another embodiment, remote device 200 is a commercially-available smart phone or tablet An Application (App) is provided to allow the smart phone or tablet to receive and display the data transmitted by the sensor device 100. In some embodiments, the Application will allow the user to send control or interrogation signals to the sensor device 1 0, all controlled by the touch screen of the smart phone or tablet. The display of data is available in a simple text form along with the date and time of data capture. Thus, any other combination of data display is also possible, including graphical form. Figures 33B, 33C and 33D show examples of a screen display of a smart phone running an App written for this embodiment.

[00223] In some embodiments, where the remote device 200 has a telecommunications capability, when the remote device 200 receives data from the sensor device 100, the remote device 200 can also transmit die data, or an alert associated with the data, to a support person such as a nurse or doctor, to allow the support person to make a decision as to whether the wound dressing needs attention.

[00224] In one embodiment, where the patient is in a hospital, the data is transmitted from the remote device 200 to another remote device operated by the support person via Wi-Fi*. In another embodiment, where the active transmitter 120/160 of the sensor device 100 is a longer-range transmitter, the sensor device 100 can communicate directly with the support person's remote device. In yet another embodiment, the remote device 200 can transmit data via the cellular telephone network or via the internet where those communications protocols are available, to provide necessary information to the support person.

[00225] The LCD controller is programmed through the receiver module (ATMegal28RF Al ) by sending the appropriate commands with required timings as recommended in the datasheet of T6963C.

[00226] The first transmitted byte consists of frame length information followed by the temperature, moisture and pressure data respectively. Upon reception frame length data is stored in TST RX LENGTH register in me receiver, while the sensor's data is ata is then sent to the LCD controller (T6963C) through a parallel interface for processing and display. The LCD controller is also programmed to display the device ID (TX device), frequency channel (2405-2480 MHz in 5M.Hz steps), and received signal strength (RSSI) in dBm.

[00227] In one experimental set up, the wound sensor 110, comprising, in this embodiment, pressure sensor 113 and moisture sensors 111. and 112, output active transmitter 120/ 60 and power source or battery 180, is attached to a mannequin leg in a room environment at about 25°C. This arrangement is shown in Figure 34A. A wound dressing is then applied over the arrangement, as shown in Figure 34B, After the wound dressing is applied, distilled water is sprayed over the dressing in the proximity of the moisture sensor ill.

[00228] Measurements are taken at intervals of S minutes as received by the remote device 200, which is placed about 3m away from the output/active transmitter 120/160. The results are shown in Table 1 below.

TABLE 1

and in a particular example, where TO is 11 :00

[00229] It will be noted that the receiver 230 sensitivity is -lOOdBm. The '"Energy" measurement represents the energy detected during packet reception.

[00230] The average values of received energy level, temperature and pressure are -79.92dBm, 23J21°C and 15.14 mmHg respectively. It will be noted that the moisture level increases gradually as the moisture soaks into the dressing over time, and the gradual drop in bandage pressure is caused by the gradual loosening of dressing layers over time.

[00231] In another experiment, a 4-layer bandage system designed to apply approximately 40mmHg at ankle level is used. Bandages are applied as per the manufacturer's instructions. Λ small slit is made in the cohesive bandage flayer 4) to allow battery connection. Allevyn™ Adhesive (Smith & Nephew) 12.5 cm x 12.5 cm dressing is applied to the lower calf and a small cut is made in the back of the dressing.

[00232] A micro-volume extension set tubing is attached to the dressing with film tape to allow injection of fluid as shown in Figure 35 A. The sensor device 100 is then attached to the lower leg (Figure 35B). The pressure sensor 13 is placed proximal to the medial malleolus between exposed skin and bandages. The moisture sensor 111 is placed at the bottom corner of AHevyn'^M dressing between exposed skin and the dressing. The resulting arrangement is shown in Figure 3SC. The results of this experiment are plotted in Figure 35D, showing a plot of the measured values of temperature, moisture and pressure obtained with different postures being adopted by the patient.

[00233] It will be appreciated that in this embodiment, the wound dressing 300 comprises two parts, being the first wound dressing to directly cover the wound, and the compression bandage to cover the first wound dressing and at least part of the sensor device 100.

[00234] The average value of the temperature during this trial is 32.83 X. The moisture values are increasing gradually as more fluid is injected into the dressing, while the pressure values are dependent on posture, being higher during walking and standing and lower during sitting or lying. It can also be observed from the graph that the pressure readings are dropping over time. This is likely because of loosening of bandage layers with movement.

[00235] In a further experiment, the pressure sensor 1.13 is placed on the posterior of the lower leg over the calf muscle 'Gastrocnemius' (Figure 36A). A small slit is made on the back corner of the dressing and the moisture sensor is then applied within the dressing to the exposed foam core of the dressing. The dressing is then subsequently re-sealed with film tape to restore normal dressing integrity. The dressing is positioned on the leg in such a way that the moisture sensor is at the distal portion of the dressing to emulate the normal flow of wound fluid due to gravity, A protective foam dressing (Mepiiex^®) is used under the circuit board to avoid direct contact with the skin. The pressure sensor 113 is located at the rear (Figure 36B) and a compression bandage applied over the sensor device 100 (Figure 36C). The results of this trial are plotted in Figure 36D.

[00236] The average value of measured temperature is 32.8 °C. As expected, the moisture readings increase gradually as fluid is injected into the dressing. The pressure values change significantly with changes in posture. This fluctuation may have been produced because of calf muscle contraction and expansion with movement.

[00237] ha another experiment, with a similar setup to those of the previous two experiments, except mat a 2-layer high stiffness bandage system (Coban™ 2) is used. Bandages are applied as per the

manufacturer's imtructions. AHevyn™ Adhesive 12.5 cm x 12.5 cm dressing is applied to the lateral aspect of the lower leg. A small cut is made on the back of the dressing and a micro-vohime extension tubing is applied to the exposed foam core of the dressing. The tubing is scaled to the dressing with a film tape to allow injection of fluid into the foam core of the dressing, while preventing leakage of fluid out of the dressing. In this trial, the pressure sensor 1 is placed on the posterior of the lower leg over the calf muscle (Gastrocnemius). The moisture sensor is applied within the Allevyn™ dressing to the e osed foam core of the dressing. The sensor device 100 is affixed outside the bandage. For moisture measurements, 1ml fluid (soy sauce diluted with water) is slowly added via the extension tubing every hour. Measurements were taken every hour and presented as a graph in Figure 37.

[00238] Since the sensor device 1 0 is placed outside the compression bandage i this experiment, the temperature sensor Is measuring the room temperature. The pressure readings are changing with the change of posture and body movement. As observed in all previous trials, the moisture readings increase gradually as the moisture sensor is soaked with the injected fluid.

[00239] A further experiment is performed using a Com aTcc SurePress* high compression elastic bandage system and Mepilex* 1 cm x 10 cm foam dressing. A small cut is made in the back of the dressing and the extension tubing is applied to the exposed foam core of the dressing. The dressing is re-sealed with film tape to restore normal dressing integrity. The pressure sensor I i 3 is placed on the posterior of the lower leg, over the calf muscle. A Mepilex* dressing is positioned on the leg over the bandages, such that the moisture sensor 111 is at the distal portion of the dressing to emulate the normal flow of wound fluid due to gravity. The fluid (soy sauce diluted with water) is slowly added via the extension tubing every hour. The measurement results are plotted in Figure 38.

[00240] A further experiment is directed to ascertaining the reliability of measurement results, and particularly the pressure measurements, since they are prone to variations due to body movements. In this trial, the sensor device 100 is covered with a transpare dh i ili l b id Th ri l i performed using a 4-layer compression system Proforc* (Sm dage system Cohan¹*¹ 2 (3M*) for pressure measurements. The pressure and moisture measurements arc performed in two separate experiments. During the pressure measurements, the moisture sensor is placed directly on exposed skin with the sensor facing the skin while the pressure sensor is placed over the flat area of the exposed skin, directly above the medial malleolus (ankle), with the sensor facing the skin, initial measurements arc taken in each experiment prior to applying bandages. The bandages arc applied in accordance with the manufacturer's instructions, maintaining 40 mmHg starting pressure. The measurement results are plotted in Figure 39 A (4- layer) and Figure 39B (2-laycr), at one minute intervals using various common postures.

[00241] As the moisture and the temperature measurements are independent of posture changes, different setups arc used from those used for bandage pressure measurement. For moisture measurements, a moisture-retentive foam dressing Allevyn™ Adhesive (Smith & Nephew) is used. A small slit is made to insert the micro-volume extension set tubing in one corner, and another slit is made to insert the moisture sensor in the opposite corner of the dressing. Since the sensor is dry, the measured moisture level is zero initially. Fluid is then injected through the nibing after every five minutes until the sensor is soaked and starts providing moisture values. After that, the dressing is placed upside down so that the fluid moves away from the sensor until it is completely depicted of moisture. Moisture measurement results from this scenario are plotted in Figure 40.

[00242] For temperature measurements, the sensing system is placed over the lower leg area with the temperature sensor facing skin, and then various temperature readings arc recorded continuously for more than 15 minutes. The experiment is performed at 23 °C room temperature, and with 40 % humidity. The temperature measurements in this scenario arc plotted in Figure 1. The average value of the measured skin temperature is 35.33 ^eC while the standard deviation (SD) was 0.93 °C for skin temperature measurements.

[00243] The above also provides a method of dressing a wound of a patient with a wound dressing, the method comprising placing at least one of the at least one pressure sensor of the sensor device of any as described herein on the patient, at or near the wound: and dressing the wound with the wound dressing including covering the at least one of tlic at least one pressure sensor with the wound dressing.

[00244] Figure 42 shows another embodiment of a sensor device platform 600 to provide a sensor device 100, fabricated on a 0.2 mm flexible printed circuit material, forming the platform 660. Examples of suitable materials for the flexible printed circuit material include polyester (PET), polyimidc (PI), polyethylene napthalare (PEN), Polyetherimide (PEl).

[00245] Figure 42 in particular, shows sensor device platform 600 for connection to four sensors 1 10,

11 1. 1 12 and 1 13 (see Figure 44). Two sensors 1 1 and 1 1 1 are pressure sensors and two sensors 1 12 and 1 13 arc moisture sensors, each interfaced (when conn d d i l f 600) i radio transmitter 120/ 160 through specialized interface or connectors 610, 620, 630 and 640 are provided for connecting die sensors i 10, 111, 112 and 1 13 to form sensor device 100 (See Figure 44),

[00246] With die use of twin pressure and moisture sensors, the system is able to measure pressure and moisture at two different locations simultaneously within a wound dressing or bandage. In normal practice, sub-bandage pressure at ankle and calf muscle is measured, while the moisture level can be measured by inserting one sensor into a foam dressing placed over the wound site and the other over normal skin for reference. The pressure sensor used in this embodiment is the FSR406 (Interlink Electronics*)) force sensor having a 38 mm x 38 mm sensing area. The moisture sensor used in this embodiment is a resistive moisture sensor HCZ-D527 (Multicomp Farnellf >)·

[00247] All the sensors are interfaced to an active radio frequency (RF) ZigBce® transmitter 120/160

ATMegal28RFAl , through dedicated interface circuits 170, 71 , 172 and 173, mounted on the rear of the sensor device 100. This radio device is chosen because it provides a single-chip solution for data acquisition, conversion, storage, and transmission. The sensor device is powered by a 6.0 V alkaline battery (not shown in mis view, which would connect to the sensor device 100 via battery interface circuit 175, A chip programming interface circuit 176 is also provided to allow for programming of the chip. Output impedance matching network 120/161 and output antenna 120 162 are also shown.

[00248] In this embodiment, sensor device platform 600 is coated with a layer of biocompatible material polydimethylsiloxane (PDMS).

[00249] Figure 43 shows sensor device platform 600 being held between thumb and forefinger, demonstrating the flexibility of the sensor device platform. Also shown is battery connector 181 connected to the sensor device platform 600 via battery interface circuit 175. In use, battery 180 is connected to battery connector 181 to power the sensor device 100.

[00250] Figure 44 shows the sensor device platform 600 connected to fee sensors 110. Ill, 112 and 113 via respective interface circuits 170, 171, 172 and 173, collectively forming this embodiment of sensor device 100.

[00251] Figure 45A shows a circuit diagram of the sensor device platform 600 and sensor device 100 of Figures 42, 43 and 44. Figure 45B shows the circuit footprint layout of the flexible printed circuit board platform 660.

[00252] The pressure sensors 110 and 111 , are provided by the FSR406 flexible force sensor for sub- bandage pressure, and the moisture sensors 112 and 113 are HCZ-D52-wire passive sensors for moisture measurement The dimensions of these sensors a x 0.5 mm respectively. The pressure sensors were calibrated and characterized for the pressure range 0-60 mroHg, while the moisture sensors were calibrated and characterized for 0-100 %RH.

[00253] The selected pressure and moisture sensors are analog passive resistive sensors ie. a change in the sensed parameter (pressure or moisture) results in a change in resistance or impedance between two output terminals of the sensors. In order to measure the parameter, the change in resistance^/impedance is transformed into a change in voltage level. For this purpose, an LM358 (Texas Instruments) mil-swing operational amplifier (op-amp) is used, along with other required circuit components. Using dedicated experimental setups and curve-fitting software, the following mathematical expressions for output voltages (in raV) were obtained for the pressure and moisture sensors, respectively.

[00254]

[00255]

[00256] where, p , = 2.533 x 10-9, p ₂ - -7.553 x 10-6, p ₃ ~ 0.012, p ₄ = -0.00921, m_t = 1.228 x 10^"*,

= 4.178 x 10-5, and m» = 0.056¾. Both equations represent nonlinear relationships between the applied quantities and respective output voltages, as shown in the graphs of Figures 46A and 46B respectively. In these graphs, the dot point indicates the maximum expected value of the respective measured parameter.

[00257] The analog voltage at the output of L 358 op-amp represents the change in the applied quantity to be measured. The voltage is converted into digital form using die in-built 10-bit analog to digital converter 15 (ADC) of the active transmitter 120/160. The ADC input range is reduced by using voltage divider circuits in both interface circuits. The digital data is then transmitted over-the-air to the receiving remote device 200. On the processing side, the original information is correctly retrieved by multiplying die received data with the voltage division factor used in the interface circuits.

[00258] The sensors' analog signals were applied to analog port F (PF0-3) of the active transmitter 120/160. Highly accurate low drop-out 400 mA, 5.0 V and 3.3 V voltage 8 regulators (TPS73250DBVT and TPS73633DB VT from Texas Instruments) were used to supply stable voltages. The sensor device 100 is powered by a 6.0 V alkaline battery 180. The active transmitter 120 160 also required an external 16.0 MHz crystal oscillator, 2.45 GHz antenna, and impedance matching network (i .e. RF balun) as previously referred to in Figure 42. A highly accurate crystal oscillator (Model: NX3225SA-16MHZ) was used to produce stable clock signals. A 500 mW chip antenna (P 2450AT18A 100 Johanson Technology®) was used along with an RF balun chip (P/N 2450FB15L0001 Johanson Technology*⁾) for RF transmission. The length and width of the copper track between the RF balun and the chip antenna were carefully selected to balance impedance between the two RF components. [00259] The IEEE 802.15.4 (ZigBeo ) wireless standard for data transmission and reception was used in this embodiment because of its long range and simple radio operations. The active transmitter 120/160 chip was programmed to capture, digitize, and transmit the sensors^* data at 5s intervals. The program starts with defining required program libraries, frame buffer, and some variables for temporary storage of information. Port F of the active transmitter 120/160 chip serves as the ADC analog input port The transceiver is run through a sequence of states, and then its transmission parameters are defined including channel frequency, data rate and output power. ext, in an endless loop, the chip is directed to capture each analog signal from the sensors in sequence, perform an ADC operation on them sequentially, and then store the result into the frame buffer for transmission. Once the complete packet of information is transmitted in the air, a frame_' transmission-end signal is generated by the active transmitter 20/160.

[00260] The transmitted information is received by a matched remote device 200 (for example as previously described with reference to Figure 18} for processing and display. An Android application (App) was developed for automatic data acquisition, processing, and display in various formats. The App displayed the transmitter device identification, received-signal strength, pressure values, moisture values, and the battery voltage of the sensor device. The App was initialized by setting the lower and the upper limits for the moisture and pressure measurements. Visual and audio alerts are provided to the user in abnormal conditions. The measured values within the defined limits are displayed in green colour, while those smaller than the lower limits appear in orange and those higher than the upper limits appear in red colour. The App also displays a text message on the screen if the sensed battery voltage drops below a defined threshold (e.g. 3.75 V).

[00261] The measured data acquired by the App is saved in the internal memory with the time of acquisition for subsequent analysis by medical professionals, in one embodiment, the App also displays the saved data in an interactive graphical form. These features are intended to help healthcare professionals in quick analysis of measured parameters for better evaluation and for generation of effective treatment plans.

[00262] In some embodiments, in which the sensor device 100 is powered through an external battery with limited power, the real-time measurements of pressure and moisture are expected to deteriorate with a drop in battery power. The measured values of pressure and moisture would then be lower than their actual values with diminishing battery power. This could eventually affect the decision making process by a healthcare professional. For instance, if the displayed pressure value is lower than it actually is, the patient or clinician may incorrectly tighten the bandage to increase the pressure to the desired level. A similar approach may also be adopted to rectify other corrupted wound parameters.

[00263] In order to determine the effect of battery power loss on the measurement process, an experiment was performed with the pressure sensor F8 406 placed on a mannequin leg powered and powered by a calibrated and precise power supply 829G ( ched to its dedicated interface circuit. An clastic compression bandage was applied over the pressure sensor to create a fixed pressure. A stable 5.0 V power was supplied to the sensor device. After validating the fixed pressure on the pressure sensor using a commercial clinical-grade pneumatic pressure meter (HP - H-23 01 ikuhime®), the output voltage of the LM358 op-amp was measured for every 100 mV drop in supply voltage until the supply voltage was reduced to 3.0 V, the minimum voltage required to operate the op-amp. The experiment was repeated for two other higher pressure values, and the resulting drops in output voltage as well as in measured pressure were recorded. It was observed that the average output voltage drop was 19.0 mV, 33.0 mV, and 96.0 mV per 100 mV drop in supply voltage for the three applied bandage pressures, respectively. The drop in measured output voltages of the LM358 op-amp and the resulting pressure measurements using Eq. (7) are plotted in Figure 47. This graph shows that the voltage drop increases with die applied pressure.

[00264] In order to obtain a precise mathematical expression for the output voltage drop per 100 mV drop in supply voltage, a MATLAB curve-fitting tool was used to obtain the following expressions of first degree polynomial, second degree polynomial, and Gaussian form, respectively.

[00265]

[00266]

[00267]

[00268]

[00269] Experiments were then performed with the sensing system powered with a 6.0 V battery, and placed on the mannequin leg wrapped with the compression bandage. Pressure measurements were recorded in the remote device. The average error produced was 1 .63 rnraHg or 37.03% with respect to the original pressure value of 53 rnrnHg at 5.0 V (Figure 48A). Measurements were men taken by repeating the same experiment using voltage drop compensation formulas in Eq. 9, Eq. 10 and Eq. .11, one at a time. The average errors obtained were 1.94 mmHg (3.66%), 2.37 mmHg (4.47%), and 2.47 19 mmHg (4,66%) for the three equations, respectively (Figures 48B, 48C and 48D).

[00270] In one embodiment, then an equation such as equation 9 above is used in the App to scale the sensed data in accordance with a voltage drop of the battery, in order to compensate for battery voltage drop.

[00273] In one embodiment, the scaling is conducted at the remote device 200. In this embodiment, the remote device 200 receives the sensed data as well as data relating to the voltage of the battery 180 at any given time. From this, the sensed data is scaled in accordance with any battery voltage drop as described above. [00272] In smother embodiment, the seating is performed at the sensor device 100 prior to transmission of the scaled sensed data. In this embodiment, a measurement of the battery voltage at any given time is used to scale the sensed data received by the sensors to provide scaled sensed dat for transmission to the remote device 200.

[00273] The sensor device 100 of Figure 44 was tested on a mannequin leg 350 (see Figure 4 A) using a common elastic compression bandage AMS Bi-Flex®. The mannequin limb mimics the curved morphology of a human bod part, and so is able to emulate realistic measurement scenarios. The sensor device 100 was placed eonformal at the centre of the leg. One pressure sensor 170 was placed near the ankle, while the other (171) was placed on the calf section. The moisture sensor 1 3 was inserted into foam dressing used to absorb moisture (only one moisture sensor was used in this experiment). The compression bandage forming part of the wound dressing was wrapped over the sensor device 100 with a reasonable tightness (Figure 49B), and the sensor device 100 was powered up with the battery 180 (not visible in this view). Approximately 3 ml distilled water was sprayed over the bandage portion close to the moisture sensor 173. The data was acquired through the remote device 200 (Figure 49C),

[00274] The pressure measurement results (Figure 50A) showed an average error of ±1.91 mniHg for pressure measurements at the calf, and ±0.70 rnmHg for those at ankle level. These results confirm the accuracy and reliability of measurements with the dropping battery voltage level, attributed to the use of the voltage compensation algorithm discussed above. The moisture measurement results (Figure SOB) indicated a gradual rise and fall in moisture levels consistent with die environment near the moisture sensor.

[00275] The performance of the sensor device 100 was also tested with experiments on a healthy human volunteer using 4-layer (Profore^) and 2-tayer (Cobart™ ) compression bandages. To measure sub- bandage pressure at two different locations, one pressure sensor 170 was placed above the ankle of the patient le 370 (Figure 51A), while the other pressure sensor 171 was placed on tile calf muscle (Figure 5 B). The complete sensor device 100 was then covered with the bandage 300 at target pressures of approximately 40 rnmHg and 25 rnmHg at ankle and calf, respectively (Figure 51C). Initial pressure readings prior to the application of bandages were recorded to find and nullify any offsets in measurements. Subsequent measurements were taken during common movement postures such as sitting, standing and walking. For each posture, five consecutive measurements were recorded.

[00276] Figures 52A, 52B and 53A, 53B show the results of pressure measurements using bom types of bandages respectively, for all selected body postures. In these Figures, the standard deviation (SD) was used as a measure of fluctuation. The SD values for each set-of-five measurements arc shown on top of respective bars. The bold horizontal line in each graph indicates the overall fluctuation (SD) with respect to average measured pressure. [00277] Since the moisture measurements do not depend on body movement, a separate test bench was used to validate moisture measurement performance of the sensor device. In this experiment as shown in Figure 54A, a 12.5 cm x 12.5 cm moisture-retentive foam dressing (Biatain® Silicone by Coloplast UK) 300 was used. This type of dressing is known to absorb wound exudate and is commonly used for moist-wound healing. A small slit was made to one corner of the dressing and the moisture sensor 173 (not visible in this view) was placed well inside the foam. The slit was scaled with t e. The sensor device 100 was powered using a 6.0 V battery 180, and initial moisture measurements wets recorded on the remote device 200. As wound fluid was not available, fluid was prepared from black coffee (to visualize the spread of fluid in the dressing) and was repeatedly injected into the foam dressing until the fluid was observed to reach the vicinity of the moisture sensor 1 2 (Figure 54B). Measurements are plotted as shown in Figure 55.

[00278] The sensor device 1 0 and sensor system 500 are thus demonstrated to provide real-time data relating to conditions underneath a wound dressing. This data can be used to determine when a wound dressing needs to be changed, whether the wound is progressing to healing, or even, if a wound dressing has not been applied correctly in the first place. The data can also be used by medical professionals to devise a plan for faster wound healing.

[00279] In one example, if sensed data relating to temperature exceeds a temperature threshold, mis can be an indication of infection, and the user can be alerted to the fact that the wound should be assessed by a medical professional.

[00280] In another example, if sensed data relating to pressure falls below a pressure threshold, this can be an indication that the wound dressing was either not applied tightly enough, or, has reduced over time due to factors such as loosening of the dressing or different postures adopted by the patient.

[0028 I f In another embodiment, if sensed data relating to pressure rises above a high pressure threshold, this can be an indication that there is too much pressure about the wound and ca trigger an alarm.

[00282] In another embodiment, if sensed data relating to moisture rises above a moisture threshold, this can indicate that the wound dressing is in danger of failing.

[00283] In some embodiments, the sensor device 100 can issue an alert to alert the patient that the dressing requires attention, or to adopt a different posture. This alert can take on any form, including an audible "beep" or alarm, actuating a vibrating element of the sensor device 100, or causing a visual element on the display to flash, light up or otherwise indicate an alert condition or action to be taken.

[00284] In another embodiment as shown in Figure 56 the sensor device 1 0 also comprises a signal generator 700 for generating a control signal 710 sensor 110, interface circuit 170, control signal generator 700 and output 120. The control signal 710 is generated in response to the sensed data. In one speci ic embodiment, the control signal 710 is generated when a measured parameter (sensed data) exceeds a parameter threshold. For example, in one embodiment, a compression bandage or wound dressing may be actively controlled to increase or decrease pressure. The generated control signal 710 can be used to control pressure increase or decrease.

[00285] In another embodiment, a fluid reserve may be provided which, in response to the control signal 700, can be caused to automatically apply more fluid into the wound dressing environment if the measured moisture parameter indicates that the moisture level has fallen below a desired moisture threshold.

[00286] In some embodiments, a different control signal is generated fo each controllable parameter such as pressure, moisture, temperature and pM level.

[00287] In one embodiment, as shown in Figure 57, the control signal(s) 710 is generated by the active transmitter 120/160, acting as the control signal generator 700. In another embodiment, the control signal(s) 710 is generated by a separate processor which processes the sensed data and generates the control signal in response to the sensed data. In one embodiment, the processor compares the sensed data with a threshold and generates the control signal(s) 7 0 when the sensed data exceeds a threshold. Each parameter sensed can have its own threshold and its own control signal generated. The output of the control signal generator (e.g. active transmitter 120/160 or a separate processor) can be connected to a control unit for a given parameter via hard wire, or, in another embodiment, the generated control signal 710 can be generated wirelessly to be received by a wireless receiver of the control unit for the given parameter.

[00288] In other embodiments, the control signal generator 700 is a passive dement such as a resistor. In other embodiments, the control signal generator is an operational amplifier, in other embodiments, control signal generator 700 is a transistor. In fact, any component, processor, arrangement or device that transforms an input signal into an output signal mat can be used as a control signal 71 , can act as the control signal generator 700.

[00289] In further embodiments, die control signal 710 is generated in response to a user command sent from the remote device 200 by the user via, for example, an App loaded onto the remote device as previously described.

[00290] In another aspect, there is provided a wound dressing incorporating at least one sensor device as previously described.

[00291] In a further embodiment, as shown in Figure 58 there is provided a sensor device platform 600 for placement in use, under a wound dressing. In rm 600 for placement in use, under a wound dressing, the sensor device platform 600 comprising at least one sensor connector 610 for connecting ½ use, a sensor 110 to the sensor device platform 600 and for receiving sensed data from the connected sensor 1 1 ; an interface circuit 170 electrically connected to die at least one sensor connector, an output 120 for allowing access to the sensed data by an external entity; a processor for processing the sensed data received from the at least one sensor connector and for providing the processed sensed data to the output; and a platform 660 supporting each of the at least one sensor connector, the output and the interface circuit.

[00292] In one embodiment, the sensor device platform 600 comprises at least one sensor connector 610 for connecting in use, a sensor 110 to the sensor device platform 600 and for receiving sensed data from the connected sensor 110. The sensor device platform 600 also comprises an interface circuit 170 electrically connected to the at least one sensor connector 610. The sensor device platform 600 also has an output 120 for allowing access to die sensed data by an external entity. The sensor device platform 600 also comprises a platform 660 supporting each, of the at least one sensor connector 610, the output 120 and die interface circuit 170.

[00293] In one embodiment, the platform 660 is flexible.

[00294] In one embodiment, the sensor device platform 600 comprises a second sensor connector 620 and a corresponding second interface circuit 171. In another embodiment, the sensor device platform 600 comprises a third sensor connector 630 and a corresponding third interface circuit 172. In another embodiment, the sensor device platform 600 comprises a fourth sensor connector 640 and a corresponding fourth interface circuit 173. In another embodiment, the sensor device platform 600 comprises at least one further sensor connector 650 and a corresponding further interface circuit 174. It will therefore be appreciated that the sensor device platform 600 can have 1, 2, 3, 4, 5, 6, 7, 8, , 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 20 to 30, 30 to 40, 40 to 50 or more than 50 sensor connectors for connection to one or more sensors.

[00295] In one embodiment as shown in Figure 59, the sensor device platform 600 is the same as the sensor device 100, with sensor connectors 610, 20, 30 and 640, and without the sensors attached. In use, the sensor device platform 600 can be manufactured separately and be provided to the user or practitioner to connect to one or more sensors via the one or more sensor connectors upon use.

[00296] In another embodiment, the sensor device platform 600 is as described with reference to Figures 42 and 43 above. [00297] In one embodiment, the sensor connector 61 is simply an electrically conductive pad for connection to an electrically conductive output of a sensor. In another embodiment, die sensor connector 610 is a mechanical connector for receiving a corresponding connector of the sensor, or for receiving an electrically conductive output lead of the sensor. In another embodiment, the sensor connector 610 is an input pin of a processor which provides the interface circuit 170 and the output 120.

[00298] In other embodiments, the data being transferred between die sensor device 100 and the remote device 200 is encrypted for security. Any suitable form of encryption can be used as will be understood by the person skilled in die art.

[00299] In another embodiment, the sensor device 100 may be miniaturized in a single chip to be sealed permanently within a wound dressing or bandage for continuous measurement of one or more wound parameters.

[00300] In some embodiments, the sensor device 200 or sensor platform 600 is disposable and in other embodiments, the sensor device 200 or sensor platform 600 is reusable. In some embodiments (particularly where the device is reusable), the sensor device 200 or sensor platform is sterilisable.

[00301] In some embodiments, the processor of the sensor device platform 600 also scales the sensed data as previously described to compensate for the battery voltage drop. In one embodiment, the scaling is done in accordance with the equation ν_ώ<ψ - 0.02598 x Vox— 2.974 where is the battery voltage drop at a given time (for example die time when the data that is being scaled is sensed) and *'_oiais the sensed d m.

[00302] There is herein also provided a method of obtaining sensed data of one or more parameters relating to a region under a wound dressing, the method comprising receiving a wireless transmission from the active wireless transmitter of the sensor device of any as described herein having an active transmitter 120/160, the wireless transmission including sensed data.

[00303] In one embodiment, data relating to battery voltage is also obtained and used to scale the sensed data to compensate for battery voltage drop over time. In one particular embodiment, the step of scaling the sensed data is perfor med according to die equation:

= 0.02598 x Vout - 2.974 where Van* is the battery voltage drop at a given time and Vout is the sensed data.

[00304] As previously described, any suitable communications protocol can be used for active transmission, and accordingly, any suitable comm ected protocol. In one embodiment, the selected communications protocol is the IEEE 802.15.4 (ZigBce* protocol) and the active transmitter 120/160 is the ATMcgal28RFAl chip by Atmel Corporation, (although any other suitable ZigBce* protocol chip ma be used, such as the CC252 RF or CC2531 transceiver chips by Texas Instruments, or the GS2000 by GainSpan Corporation). In another embodiment, in which the selected cornmunications protocol is IEEE 802.15.1-xxxx (Bluetooth*), suitable active transmitters 120/160 may include the CC256X range from Texas Instruments Incorporated. In embodiments where the selected protocol is the Bluetooth* Low Energy (BLE) standard, suitable active transmitter 120/160 may include the CC2564, CC254x range (including the CC 2540 chip) by Texas Instruments Incorporated. In embodiments in which the selected protocol is the Wi-Fi* (IEEE 802. llxx) protocol, suitable active transmitters may include the CCS 100 and CC320 chips by Texas Instruments Incorporated. In embodiments where the selected transmitter 120 is an RFID device, suitable devices may include the TMS370S chip from Texas Instruments Incorporate, and in a near field communications (NFC RF1D) application, a suitable device may include the TRF796X range from Texas Instruments Incorporated

[00305] In different such embodiments, a sensor device platform 600 would appear for example in one embodiment, as shown in Figure 59 with the transmitter device 120/160 replaced by the appropriate protocol and selected device as described above. A sensor device 100 would appear for example in one embodiment, as shown in Figure 18 with the transmitter device 120/160 replaced by the appropriate protocol and selected device as described above. A remote device 200 would appear for example in one embodiment, as shown in Figure 18 with the remote device transceiver 230 replaced by the appropriate protocol and selected device as described above. A sensor system 500 would appear for example in one embodiment, as shown in Figure 1 with the transmitter device 120/160 and the remote device transceiver 230 replaced by the appropriate protocol and selected device as described above.

[00306] The type of data produced by the sensor system 500 can also be useful in determining other factors and relationships to improve wound care in the future. For example, statistical analysis of collected data may reveal further correlations between certain parameters and the speed and quality of wound healing. Such data may result in a better understanding of wound dressin design, or a better understanding of appropriate postures for the patient to adopt or conversely, to avoid.

[00307] In yet other applications, the sensed data can provide other real-time information relating to the patient in general. For example, in one embodiment, if one or more of the sensors 110 is a movement detector, such as an inertial sensor or a mercury switch, it can be determined if the patient to which the sensor device 100 is attached, adopts a particular position such as becoming vertical, which would suggest that the patient is out of bed and or walking. In such circumstances, the sensor system 500 can alert a carer to the action of the patient [00308] it will be appreciated that any number of different sensors 110 and combinations of such sensors can be connected to sensor device platform 600 to provide a customised sensor device 100 for a given patient, and to provide numerous types of sensed data as may be required for a given patient.

[00309] Throughout the specification and the claims that follow, unless the context requires otherwise, the words "comprise" and "include" and variations such as "comprising" and "including" will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

[00310] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.

[00311] It will be appreciated by those skilled in the art that the various aspects are not restricted in their use to the particular application described. Neither arc the various aspects restricted in their described embodiments with regard to the particular elements and or features described or depicted herein. It will be appreciated that the various aspects are not limited to the embodiment or embodiments disclosed, but arc capable of numerous rearrangements, modifications and substitutions without departing from the scope as set forth and defined by the following claims.

[00312] For example, while the various embodiments described herein have been described having one output, it will be understood that multiple outputs can also be provided in some embodiments. For example, in one embodiment, the sensed data from the sensors are shared between two outputs. In another embodiment, each sensor is provided with its own output and in another embodiment, an output is provided for each parameter sensed. Different types of outputs can also be provided in a single sensor device. For example, in one embodiment, sensor device ! 00 comprises as outputs, an electrical connector, a passive transmitter and an active transmitter.

[00313] Those of skill in the art would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software or instructions, or combinations of both. To clearly illustrate this intercbangeabiliry of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scopes described herein. [00314] The steps of a method r algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. For a hardware implementation, processing may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. Software modules, also known as computer programs, computer codes, or instructions, may contain a number a number of source code or object code segments or instructions, and may reside in any computer readable medium such as a RAM memory, flash memory, ROM memory, EPROM memory, registers, hard disk, a removable disk, a CD-ROM, a DVD-ROM, a Blu-ray disc, or any other form of computer readable medium. In some aspects the computer-readable media may comprise non- transitory computer-readable media (e.g., tangible media). In addition, for other aspects computer-readable media may comprise transitory computer- readable media (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media. In another aspect, the computer readable medium may be integral to the processor. The processor and the computer readable medium may reside in an ASIC or related device. The software codes may be stored in a memory unit and the processor may be configured to execute them. The memory unit may be implemented within the processor or externa! to the processor, in which case it can be communicatively coupled to the processor via various means as is known in the art.

[00315] Further, it should be appreciated mat modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and or otherwise obtained by computing device. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a computing device can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

[00316] in one form various aspects may comprise a computer program product for performing the method or operations presented herein. For example, such a computer program product may comprise a computer (or processor) readable medium haying instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For certain aspects, the computer program product may include packaging material.

[00317] The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actio t departing from the scope of the claims, la other words, unless a specific order of steps or actions is specified, die order and/or use of specific steps and or actions may be modified without departing from the scope of the claims.

[00318] As used herein, the term '^ieten ra^ For example,

"determining" may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, "determining" may include receiving (e.g.. receiving information), accessing (e.g., accessing data i a memory) and the like. Also, "determining" may include resolving, selecting, choosing, establishing and the like.

Claims

1. Λ flexible sensor device comprising:

at least one parameter sensor for placement under a wound dressing in use and for sensing a parameter under die wound dressing and for generating sensed data relating to the sensed parameter; and

an output for allowing the sensed, data to be retrieved white the at least one parameter sensor remains under the wound dressing.

2. A flexible sensor device as claimed in claim J wherein the output is a connector to a memory storing the sensed data.

3. A flexible sensor device as claimed in claim 1 wherein the output is a passive wireless

transmitter.

4. A flexible sensor device as claimed in claim 1 wherein the output is an active wireless

transmitter for receiving the sensed data from the at least one parameter sensor and for transmitting the sensed data to a remote receiver.

5. A flexible sensor device as claimed in claim 4 wherein the active wireless transmitter

transmits at least a portion of the sensed data at predetermined intervals.

6. A flexible sensor device as claimed in any one of claims 1 to 5 wherein the flexible sensor device generates an alert when the sensed data exceeds a threshold.

?. A flexible sensor device as claimed in any one of claims I to 6 further comprising:

an interface circuit disposed between the at least one parameter sensor and the output to provide the sensed data from the at least one parameter sensor to the output.

8. A flexible sensor device as claimed in any one of claims 1 to 7 wherein at least a portion of a pathway between the at least one parameter sensor and the output is flexible.

9. A flexible sensor device as claimed in claim 8 wherein the at least a portion of a pathway is a flexible conductive wire.

10. A flexible sensor device as claimed in claim 7 wherein at Least one of the at least one

parameter sensor, the output and the interface circuit is disposed on a flexible substrate.

11. A flexible sensor device as claimed in claim 10 wherein each of the at least one parameter sensor, (he output and the interface circuit is disposed on the flexible substrate.

12. A flexible sensor device as claimed in any one of claims 1 to 11 wherein the parameter sensed by the at least one parameter sensor comprises any one of temperature, pressure, moisture and PH.

13. A flexible sensor device as claimed in any one of claims 1 to 12 further comprising a second parameter sensor for sensing any one of temperature, pressure, moisture and pH.

14. A flexible sensor device as claimed in claim 13 former comprising a third parameter sensor for sensing any one of temperature, pressure, moisture and pH.

15. A flexible sensor device as claimed in claim 14 further comprising a fourth parameter sensor for sensing any one of temperature, pressure, moisture and pH.

16. A flexible sensor device as claimed in claim IS further comprising at least one further

parameter sensor for sensing any one of temperature, pressure, moisture, pH and at least one further parameter.

17. A flexible sensor device as claimed in any one of claims 1 to 16 further comprising a control signal generator for generating a control signal in response to the sensed data.

18. A sensor device comprising:

at least one parameter sensor for placement under a wound dressing in use and for sensing a parameter under the wound dressing and generating sensed data relating to the sensed parameter; and

an active wireless transmitter for receiving data from the at least one parameter sensor and for transmitting the sensed data to a remote device.

19. A sensor device as claimed in claim 18 wherein the active wireless transmitter transmits at least a portion of the sensed data at predetermined intervals.

20. A sensor device as claimed in claim 1 wherein the active wireless transmitter transmits data at a range of greater than about 0.05m.

21. A sensor device as claimed in claim 20 wherein the active wireless transmitter transmits data at a range of between about 4m and about 5m.

22. A sensor device as claimed in any one of claims 16 to 21 wherein the active wireless

transmitter transmits the data according to the IEEE 802.15.4 standard (ZigBee*).

23. A sensor device as claimed in any one of claims 18 to 22 further comprising:

an interface circuit disposed between the at least one parameter sensor and the active wireless transmitter to provide the sensed data from the at least one parameter sensor to the active wireless transmitter.

24. A sensor device as claimed in any one of claims 18 to 23 wherein at least a portion of a

pathway between the at least one parameter sensor and the active wireless transmitter is flexible.

25. A sensor device as claimed in claim 24 wherein the at least a portion of a pathway is a

conductive wire.

26. A sensor device as claimed in any one of claims 23 to 25 wherein at least one of the at least one parameter sensor, the output and the interface circuit is disposed on a flexible substrate.

27. A sensor device as claimed in claim 26 wherein each of the at leas one parameter sensor, the output and the interface circuit is disposed on the flexible substrate.

28. A sensor device as claimed in any one of claims IS to 27 wherein the parameter sensed by the at least one parameter sensor comprises an one of temperature, pressure, moisture and pH.

29. A sensor device as claimed in any one of claims 18 to 28 further comprising a second

parameter sensor for sensing any one of temperature, pressure, moisture and pH.

30. A sensor device as claimed in claim 29 further comprising a third parameter sensor for sensing any one of temperature, pressure, moisture and pH.

31. A sensor device as claimed in claim 3Q further comprising a fourth parameter sensor for

sensing any one of temperature, pressure, moisture and pH.

32. A sensor device as claimed in claim 31 further comprising at least one further parameter sensor for sensing any one of temperature, pressure, moisture, pH and at least one further parameter.

33. A sensor device as claimed in any one of claims 18 to 32 wherein the sensor device generates an alert when the sensed data exceeds a threshold.

34. A sensor device as claimed in any one of claims 1 to 33 further comprising a control signal generator for generating a control signal in response to the sensed data.

35. A sensor device comprising:

at least one pressure sensor for placement under a wound dressing in use and for sensing pressure under the wound dressing and generating sensed data; and

an output for allowing the sensed data to be retrieved while the at Least one parameter sensor remains under the wound dressing.

36. A sensor device as claimed in claim 35 wherein the output is a connector to a memory storing the sensed data.

37. A sensor device as claimed in claim 35 wherein the output is a passive wireless transmitter.

38. A sensor device as claimed in claim 35 wherein the output is an active wireless transmitter for receiving the sensed data from the at least one pressure sensor and for transmitting the sensed data to a remote receiver.

39. A sensor device as claimed in claim 38 wherein the active wireless transmitter transmits at least a portion of the sensed data at predetermined intervals.

40. A sensor device as claimed in any one of claims 35 to 39 wherein the sensor device generates an alert when the sensed data exceeds a threshold.

41. A sensor device as claimed in any one pf claims 35 to 40 further comprising:

an interface circuit disposed between the at least one pressure sensor and the output to provide the sensed data from the at least one pressure sensor to the output

42. A sensor device as claimed in any one of claims 35 to 41 wherein at least a portion of a

pathway between the at least one pressure sensor and the output is flexible:

43. A sensor device as claimed in claim 42 wherein the at least a portion of a pathway is a

conductive wire.

44. A sensor device as claimed in claim 43 wherein at least one of the at least one pressure sensor, the output and the interface circuit is disposed on a flexible substrate.

45. A sensor device as claimed in claim 44 wherein each of the at least one pressure sensor, the output and the interface circuit is disposed on the flexible substrate.

46. A sensor device as claimed in any one of claims 33 to 43 further comprising a second sensor for sensing any one of temperature, pressure, moisture and pH.

47. A sensor device as claimed in claim 44 further comprising a third sensor for sensing any one of temperature, pressure, moisture and pH.

48. A sensor device as claimed in claim 45 further comprising a fourth sensor for sensing any one of temperature, pressure, moisture and pH.

49. A senso device as claimed in claim 48 further comprising at least one further parameter sensor for sensing any one of temperature, pressure, moisture, pH and at least one further parameter.

50. A sensor device as claimed in any one of claims 35 to 49 further comprising a control signal generator for generating a control signal in response to the sensed data.

51. A wound dressing incorporating at least one sensor device as claimed in any one of claims I to 50.

52. A method of dressing a wound of a patient with a wound dressing, the method comprising:

placing at least one of the at least one pressure sensor of the sensor device of any one of claims 35 to 49 on the patient, at or near the wound; and

dressing the wound with the wound dressing including covering the at least one of the at least one pressure sensor with die wound dressing.

53. A method as claimed in claim 52 further comprising covering the entire sensor device with the wound dressing.

54. A method of dressing a wound of a patient with a wound dressing, the method comprising:

placing at least one of the at least one parameter sensor of die sensor device of any one of claims 1 to 50 on the patient, at or near the wound; and

dressing the wound with the wound dressing including covering the at least one of the at least one parameter sensor with die wound dressing.

55. A method as claimed in claim 54 further comprising covering the entire sensor device with the wound dressing.

56. A method of obtaining sensed data of one or more parameters relating to a region under a wound dressing, the method comprising:

receiving a wireless transmission from the active wireless transmitter of the sensor device of any one of claims 4 to 17, 18 to 34 and 38 to 50, the wireless transmission including sensed data.

57. A method of obtaining sensed data of one or more parameters relating to a region under a wound dressing, the method comprising:

wirelessiy downloading the sensed data from the passive transmitter of the sensor device of any one of claims 3 or 37.

58. A method of obtaining sensed data of one or more parameters relating to a region under a wound dressing, the method comprising:

connecting an electrical connector to the connector of the sensor device of any one of claims 2 or 37; and

accessing the sensed data from the memory of the sensor device.

59. A method as claimed in any one of claims 56 to 58 wherein data relating to battery voltage is also obtained and used to scale the sensed data to compensate for battery voltage drop over time.

60. A method as claimed in claim 59 wherein the step of scaling the sensed data is performed according to the equation:

where

is the battery voltage drop at a given time and V^is the sensed data.

61. A system for obtaining sensed data of one or more parameters relating to a region under a wound dressing, the system comprising:

a sensor device as claimed In any one of claims 1 to 50 for sensing and outplacing the sensed data; and

a remote device for receiving the output sensed data.

62. A system as claimed in claim 1 wherein die remote device is a smart phone or tablet and wherein the system further comprises a smart phone or tablet application for processing and displaying the output sensed data

63. A system as claimed in claim 61 wherein the smart phone or tablet application also receives commands via the smart phone or tablet and transmits the commands to the sensor device.

64. A sensor device platform for placement in use, under a wound dressing, the sensor device platform comprising:

at least one sensor connector for connecting in use, a sensor to the sensor device platform and for receiving sensed data from the connected sensor;

an interface circuit electrically connected to the at least one sensor connector;

an output for allowing access to the sensed data by an external entity;

a processor for processing the sensed data received from the at least one sensor connector and for providing the processed sensed data to the output and a platform supporting each of the at least one sensor connector, the output and the interface circuit

65. A sensor device platform as claimed in claim 64 wherein the platform is flexible.

66. A sensor device platform as claimed in any one of claims 64 or 65 further comprising a

second sensor connector and a corresponding second interface circuit

67. A sensor device platform as claimed in claim 64 further comprising a third sensor connector and a corresponding third interlace circuit.

68. A sensor device platform as claimed in claim 65 further comprising a fourth sensor connector and a corresponding fourth interface circuit

69. A sensor device platform as claimed in claim 66 further comprising at least one further sensor connector and a corresponding further interface circuit.

70. A sensor device platform as claimed in any one of claims 65 to 69 further comprising a control signal generator for generating a control signal in response to the sensed data.

71. A sensor device platform as claimed in any one of claims 64 to 70 wherein the output is an active transmitter for irclcssly transmitting the sensed data to a remote device.

72. A sensor device platform as claimed in any one of claims 64 to 71 wherein in use, the

processor scales the sensed data in accordance with battery voltage drop.

73. A senso device platform as claimed in claim 72 wherein the scaling is performed according to the equation:

where is the battery voltage drop at a given time and ^is die sensed data.