GB2573490A - A fall sensing system - Google Patents

Abstract

Fall sensing unit 2 includes sensing means 12 to detect motion indicative of freefall and motion indicative of impact. Processing means 13 receives and assesses input from the sensing means 12 and outputs an alarm signal via wireless communication means 14 if the assessed input indicates that a fall event has occurred. The sensing means may be a three-axis accelerometer. A fall event may be recorded when freefall motion lasts at least 20 milliseconds. The unit may include a piezo-electric buzzer to provide an audio alert and an eccentric rotating mass motor. In a second aspect, a fall sensing system includes a plurality of fall sensing units. Communication between units allows a closed group network to be formed. In a further aspect, a fall sensing system includes at least one fall sensing unit and a mobile device. The fall sensing unit and the mobile device communicate to form a closed group network.

Description

The present invention relates to a fall sensing system. More particularly, the present invention relates to a fall sensing system for falls from height. Even more particularly, the present invention relates to a fall sensing and alarm system for alerting personnel that a fall has occurred.

BACKGROUND

Falls from height are the biggest source of injury and death in industry, for example in areas such as construction, roofing, scaffolding, utility construction and maintenance, wind turbine construction and maintenance, tree surgery, and many others.

There are a number of known devices that are intended to assist with preventing falls, or to assist with arresting the descent of an individual who has fallen from height, before they can impact the ground. These devices include prevention products such as edge railings/barriers, and physical and mechanical fall arrest products such as tethered harnesses and ropes. Responsible employers and end users have widely adopted these devices. However, these types of devices only act as passive prevention (barriers) or (for harnesses and ropes) only address the initial part of the problem of falling from height - that is, the prevention of a long drop, or ground impact following a long drop, once an individual has fallen. These products do not offer a follow-on solution once the initial fall has been prevented or arrested.

There are several potential follow-on problems that can occur after an initial fall. For example, if a worker wearing a tethered harness falls off a roof edge, the tethered harness will physically prevent them impacting the ground, but the worker may still be injured or made unconscious from the accident. They may also be tied up in the harness or ropes, which can cause critical blood circulation dangers (orthostatic intolerance). It is therefore essential in all fall events that emergency assistance gets to the victim as soon as possible. This is often explicitly required by law, with employers required to assess risk at their work sites, and adopt a plan detailing how they will respond quickly to an incident such as a fall.

In the event that a fall occurs where there is no arrest device, or where the device fails and a fall accident occurs, it is particularly critical that emergency assistance gets to the victim as soon as possible. However, other workers may be working in different areas of the work site and not within sight or hearing of their colleagues (especially if it is a noisy environment). If a worker falls, their colleagues may not immediately be aware of this, and may not hear or be able to hear any cries for help. Emergency assistance will only be summoned if/when someone eventually discovers what has happened, and this may be too late.

Furthermore, when a person works alone (lone worker) at height, they will have no colleagues nearby to notice a fall and call for help, and, if the site is remote, they may not be able to rely on other people or passers-by such as members of the public. Therefore their life is critically at risk in a fall event, even if using physical fall prevention products.

A number of devices are known for detecting falls or similar. For example, elderly or medical care fall sensors are commonly used in homes or similar, where an older person or a person with medical problems is at risk of falling to the floor from a standing position. The user (elderly person) wears a fall sensor system, and when certain conditions are met, a signal is sent by the system to a monitoring station located elsewhere, to communicate distress and summon assistance. The fall sensors in these systems typically detect tilt (i.e. when a person has gone from vertical to horizontal), lack of motion and rotation. The system is programmed with the assumption that if the sensor is horizontal and not moving for an extended time period, then a fall has taken place.

Man down, or lone worker alarms are also known, such as those manufactured by 'Skyguard', or 'Lone Alert' in the UK, and 'Black Line Safety' in the US. In use, a worker wears one of these devices, and can summon assistance or talk to an operator by pressing a button. These systems may also have GPS location and fall detection. These types of system are popular with workers who visit the public at their home (e.g. council staff, law enforcement, utility workers) where the worker is potentially at risk. The fall detection system in these types of devices typically detects tilt (i.e. fall from vertical standing position to horizontal on the floor), lack of motion, impact, and rotation.

Fall alert apps are also available for use with mobile devices. These use the built-in internal accelerometer facility present in most modern smartphones. The user puts the phone in a pocket with the fall App running, and if it detects a fall it contacts offsite for help.

CN203352806 shows and describes a wireless sensor network system for field rescue. The wireless sensor network system comprises information gatherers, a communicator and a wireless monitoring host. The information gatherers are installed in various field rescue equipment, the communicator is carried by a rescue worker, the information gatherers are connected to the communicator by wireless network, and the communicator is interconnected with the wireless monitoring host by the wireless network. Each information gatherer comprises an environment condition acquisition module, a personnel positioning module, a vital signs information acquisition module and an equipment condition acquisition module. The wireless sensor network system is adapted to a complex rescue environment. Acquired field environment information, equipment condition information, rescue worker positional information and vital signs information are transmitted to the wireless monitoring host by the information gatherers through the communicator, more field information is supplied for scientific decision and command of emergency field managers, and therefore rescue efficiency is improved, life and property losses are minimized, and safety guarantee level for field emergency rescue workers is raised.

EP2269088 describes and shows a wireless information and safety system for mines, which is capable of continuous tracking and monitoring of underground miners' and equipment movement in real-time. The wireless information and safety system comprises a combination of hardware and software. Radio Frequency Identification (RFID) devices are provided with a resident hardware specific embedded software for programming the RFID devices to function as coordinator, router and end devices. Application software and a wireless sensor network is provided fortracking, monitoring and storing of information received from RFID devices placed at strategic locations of a mine.

US7280040 describes and shows a system and method of creating and maintaining a communications network. The system includes a wearable system, a deployable system, an array of physiological sensors, an array of environmental sensors, and the integration of these into a multi-nodal voice and data communication system. The primary communications network is composed of body-worn communications nodes comprising sensors, wearable audio/video communications gear, and wireless digital transceivers. The deployable system supports and extends the body-worn network by providing wider communications coverage, situational environmental monitoring, and navigational aid. The deployable system is composed of small, selfcontained, robust network nodes. Each such node combines environmental sensors, a digital wireless “repeater,” and a navigational beacon capability integrated in a hardened, robust package. Nodes are carried by team members and deployed when needed to extend the range of the communications or sensor network.

US2009322513 describes and shows a medical emergency reporting system and methodology that utilises a wearable monitoring device to continuously monitor key physiological parameters of a person. In use, when measurements exceed programmed threshold levels, it will automatically issue a medical emergency alert along with location information to a remote monitoring centre via a wireless network. The system also provides manual emergency alert activation.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.

SUMMARY

It is an object of the present invention to provide a fall sensing system which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

It is a further object of the invention to provide a fall sensing system for falls from height which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

It is a yet still further object of the invention to provide a fall sensing and alarm system for alerting personnel on and off a work site that a fall has occurred which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

The term “comprising” as used in this specification and indicative independent claims means “consisting at least in part of”. When interpreting each statement in this specification and indicative independent claims that includes the term “comprising”, features other than that or those prefaced by the term may also be present. Related terms such as “comprise” and “comprises” are to be interpreted in the same manner.

As used herein the term “and/or” means “and” or “or”, or both.

As used herein “(s)” following a noun means the plural and/or singular forms of the noun.

Accordingly, in a first aspect the present invention may broadly be said to consist in a fall sensing unit, comprising: a sensing means configured to detect motion indicative of freefall and motion indicative of impact; a communication means configured to transmit signals wirelessly; a processing means configured to receive and assess input from the sensing means and to output an alarm signal via the communication means if the assessed input indicates that a fall event has occurred.

In an embodiment, the sensing means comprises an accelerometer.

In an embodiment, the accelerometer comprises a three-axis digital accelerometer.

In an embodiment, the processing means comprises a microprocessor.

In an embodiment, the microprocessor is configured to record that a fall has occurred if freefall motion lasts at least 20 milliseconds.

In an embodiment, the communication means comprises RF transceiver modules configured for short, mid and long range wireless communication.

In an embodiment, the RF transceiver modules comprise an RF transceiver module configured as a short/long range transceiver, and a dedicated short/mid range RF transceiver module.

In an embodiment, the short/long range transceiver comprises an RF transceiver module configured to operate in the range 2.405-2.475GHz of the ISM band.

In an embodiment, the short/mid range RF transceiver module is configured to operate in the range 2.402-2.480GHz of the ISM band.

In an embodiment, the short/mid range RF transceiver module comprises a Bluetooth module.

In an embodiment, the communication means comprises a wireless communication module.

In an embodiment, the fall sensing unit further comprises an audio alert means, configured to activate on receiving the alarm signal.

In an embodiment, the audio alert means comprises a piezo-electric buzzer.

In an embodiment, the fall sensing unit further comprises a vibrating means, configured to activate on receiving the alarm signal.

In an embodiment, the vibrating means comprises at least one eccentric rotating mass motor.

In an embodiment, the fall sensing unit further comprises a housing configured to surround and contain the sensing means, communication means and processing means, and; a means for securing the housing in position on a belt or harness.

In an embodiment, the means for securing the housing in position comprises a flap connected to and extending from the housing to wrap around and hold the fall sensing unit in position on a belt or harness.

In an embodiment, the fall sensing unit further comprises one or more of: an on/off means; a device status indicator; a connection/disconnection means; a means to connect a battery charger, all located for viewing and/or access from the exterior of the housing.

In an embodiment, the on/off means comprises a switch; the device status indicator comprises a display LED; the connection/disconnection means comprises a connect button; and; the means to connect a battery charger comprises a USB socket.

In an embodiment, the flap and housing are configured so that the on/off switch, display LED, connect button, and USB socket are user visible and/or user accessible in use.

In an embodiment, the processing means is further configured to output an alarm signal via the communication means if two taps are detected in quick succession.

In a second aspect the present invention may broadly be said to consist in a fall sensing system, comprising: two or more fall sensing units as outlined in any one of the preceding statements; the fall sensing units configured so that the communication means can transmit and receive information between units to allow a closed group network to be formed from the units.

In an embodiment, once a closed group network has been formed, the alarm signal transmitted in the event of any single fall sensing unit detecting a fall event will be transmitted to each fall sensing unit within the network.

In an embodiment, the transmitted and received information comprises the unique serial number of the transmitting fall sensing unit.

In an embodiment, the receiving unit is configured to copy the unique serial number to become a copy of the transmitting unit.

In an embodiment, the fall sensing unit is further configured so that a user can disconnect the unit from the network.

In a third aspect the present invention may broadly be said to consist in a fall sensing system, comprising: at least one fall sensing unit as outlined in any one of the preceding statements relating to a fall sensing unit; a mobile device; the mobile device and one of the at least one fall sensing units mutually configured so that information can be transmitted and received between the one fall sensing unit and the mobile device, and between the fall sensing units, to allow a closed group network to be formed; the mobile device further configured to transmit an emergency message on receiving an alarm signal from the one fall sensing unit.

In an embodiment, once a closed group network has been formed using multiple fall sensing units, the alarm signal transmitted in the event of any single fall sensing unit detecting a fall event will be transmitted to each fall sensing unit within the network.

In an embodiment, the transmitted and received information comprises the unique serial number of the transmitting fall sensing unit.

In an embodiment, the mobile device is configured to copy the unique serial number of the one fall sensing unit.

In an embodiment, the fall sensing unit is further configured so that a user can disconnect a fall sensing unit from a network.

In an embodiment, the mobile device is configured to transmit the emergency message as an SMS text message.

In an embodiment, the fall sensing unit is further configured so that any other fall sensing unit within a previously-formed network that is not already connected to a mobile device can be connected to another mobile device.

With respect to the above description then, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

BRIEF DESCRIPTION OF THE FIGURES

Further aspects of the invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings which show an embodiment of the device by way of example, and in which:

Figure 1a shows a perspective view from above and to one side of an embodiment of a fall sensing unit that forms part of the fall sensing system of the present invention system, the fall sensing unit connecting to the belt or harness of a user, the fall sensing unit comprising a housing configured as a container for other elements of the fall sensing unit, the housing connecting in use to the user's belt or harness via a fabric strap that extends from the housing to wrap around the belt and back around the housing to connect in place via a hook-and-loop fastener, the strap shown in an open position.

Figure 1 b shows the underside or end view of the housing of the fall sensing unit of figure 1a.

Figure 2a shows the fall sensing unit of figure 1 with the strap in a closed position.

Figure 2b shows a variation of the fall sensing unit of figure 1, the fabric strap extending from the housing to wrap around the belt and back around the housing to connect in place via a hook-and-loop fastener that forms part of the strap.

Figure 3a shows a schematic view of the elements within the housing that form the internal portion of the fall sensing unit, and the connections between these elements.

Figure 3b shows an alternative schematic view of the elements within the housing that form the internal portion of the fall sensing unit, and the connections between these elements, for a variation of the fall sensing unit, the fall sensing unit in this alternative embodiment having a code switch, used when forming a closed network fall sensing system from a number of individual fall sensing units.

Figure 4 shows an example of a code switch as used with the alternative form of fall sensing unit of figure 3b.

Figure 5 shows a schematic view of a number of fall sensing units wirelessly connected to form a network, each of the fall sensing units connected to and communicating with each of the others in the network, fall sensing units able to be added to or removed from the network.

Figure 6 shows a schematic view of a number of fall sensing units wirelessly connected to form a network, each of the fall sensing units connected to and communicating with each of the others in the network, one or more of the fall sensing units connected to a mobile device.

Figure 7 shows a single fall sensing unit connected to a mobile device, for a 'lone worker' scenario.

DETAILED DESCRIPTION

Embodiments of the invention, and variations thereof, will now be described in detail with reference to the figures.

The overall fall sensing system 1 is formed by networking a number of separate items, the main item(s) in the network comprising separate/individual fall sensing units 2, as described below.

Fall Sensing Unit

As shown in figures 1 and 2a, the fall sensing unit 2 of the preferred embodiment system comprises a box or housing 21 within which a sensor, and associated circuitry, power, and communication elements , are contained. These items will be described in detail below.

A fabric wrap or flap 4 is integrally connected to, and extends from, one edge of the housing 21. In use, the flap 4 wraps around the housing 21 and a user's belt or harness 3 so that a portion of the wearer or user's belt or harness 3 is located between the flap 4 and the housing 21. A first patch or first area 5 at or close to the free end of the flap 4 (away from the integrally connected end) is formed of one part or component of a hook-and-loop fastener material. In use, this secures to a second patch 8 formed from the second or complementary part or component of the hookand-loop fastener material, which is located on the housing 21, so that the first and second patches 5, 8 can be brought together to securely hold the housing 21 in position on the user's belt/harness 3.

In variations or different embodiments, the fall sensing unit 2 could be used with a belt pouch or similar, separate to the housing and it's contents, instead of or as well as having an integral fabric wrap. The pouch would attach to a belt or harness via a belt loop or similar on the pouch, or a flap similar to flap 4 described above that extends from the main body of the pouch.

As shown in figure 2b, in a variation of the fall sensing unit of the embodiment described above and as shown in figures 1 and 2a, the fabric strap wraps around the housing and attaches to itself via the second hook-and-loop fastener patch, that in this variation is located on the strap itself (rather than on the housing as in the embodiment of figure 1), in order to connect the fall sensing unit to a user's belt or harness.

The exterior of the housing 21 comprises a number of outlet ports, switches and displays. In this embodiment, an on/off switch 6 and a display LED 7 are located on the top or upper surface of the housing 21, a buzzer vent 9 is located on one or more sides of the housing 21, and a connect button 10 and USB socket 11 are located on the bottom surface of the housing 21. The connect button 10 is used to connect the sensor unit to an existing group/network of sensor units, or when creating a new group/network, as described in detail below. The connect button 10 can also be used to disconnect a sensor unit from a group/network. The flap 4 in this embodiment is formed with integral apertures and gaps so that in use, with the flap 4 wrapped around the housing, the on/off switch 6, the display LED 7, and other elements, can be viewed and accessed as required, and sounds from the buzzer vent 9 can be clearly heard. In variations, the apertures/gaps could be formed as transparent viewing windows. The flap could also be formed with no apertures/gaps/windows.

In this embodiment, the housing 21 contains a battery 16 and a charging unit 20, a three-axis digital accelerometer 12, a microprocessor 13, and a communication module 14, plus circuitry and connections to interconnect these elements and allow intercommunication between them as required. These elements and their interconnections are shown schematically in figure 3a for the preferred embodiment, and figure 3b for a variation of this embodiment, along with other elements suitable for operation of the embodiment shown and described.

The specialist electronic modules (accelerometer 12, communications module 14, microprocessor 13), together with a number of other passive and active electronic components (battery charger 20, USB charging socket 11, status LEDs 7, etc) are connected to a compact double-sided printed circuit board. The operating software embedded in the microprocessor 13 controls all aspects of the electronic systems within the sensor unit.

The communication module 14 comprises two main sub-modules: a fully IEEE, FCC and R&TTE certified 2.4GHz (worldwide ISM band) RF transceiver module 14a, configured to operate in the range 2.405-2.475GHz of the ISM band, and further configured to provide long and short range/distance ZigBee wifi wireless network communications, and a Bluetooth 4.1 low energy RF transceiver module 14b to provide short and medium range/distance wireless communication in the range 2.402-2.480GHz of the ISM band.

The wireless communication of RF transceiver module 14a is configured so that it is suitably long range, in order to cover a large work site. The RF transceiver module 14a is required for long range communication, but this transceiver module can and does also work at short range (e.g. when connecting sensing units together). However, RF transceiver module 14a requires relatively high power in operation.

The Bluetooth transceiver module 14b is used for short and mid- range communication only when the sensor unit is used with a mobile device. For example, if a lone worker up a tree or on a roof is using the fall sensing system with a single fall sensing unit 2 connected to a mobile device (see below for details).

The accelerometer 12 is a low power, three-axis, capacitive micro-machined digital accelerometer. The accelerometer 12 is configured to accurately and reliably detect movement indicative of freefall (approximately 0~1g force), and impact. In use, data from the accelerometer 12 is transmitted to the microprocessor 13.

The microprocessor 13 is configured to receive the input data from the accelerometer 12, and to process this and provide an output based on the input. The output or outputs are intended to indicate when a fall and/or impact has occurred, or a similar emergency situation. When freefall (or impact after freefall) is detected by the accelerometer 12 (e.g. a worker falling from a roof or similar), the microprocessor 13 will receive the input, and, if other pre-specified criteria are within or outside pre-set limits, will record that a fall event has occurred and send instructions to the communication module 14 to transmit as appropriate. The settings and operation of the microprocessor 13 will be described in more detail in the 'use' section below.

The housing 21 and it's contents, plus the wrap 4, form an individual sensor unit 2.

The on-off switch 6 is, in this embodiment, a slide switch. The switch powers the sensor unit on or off. In this embodiment, the switch 6 is recessed so as not to be accidentally turned off during use.

The display LED 7 is, in this embodiment, a tri-coloured LED indicator configured to show status as follows:

• Purple solid: on power-up the sensor unit requires some time (approximately three seconds) to initialise. When the purple LED turns off the sensor unit is ready to connect and/or use.

• Green intermittent flash: high battery level.

• Blue intermittent flash: medium battery level.

• Red intermittent flash: low battery level. At this point, the sensor won’t operate properly and the battery must be recharged.

In this embodiment, the sensor unit is powered by two 1,2v 2000mAh AA Nickel Metal Hydride rechargeable high capacity batteries 16. The batteries can be charged via the USB connector 11, and the charging unit 20.

When recharging (i.e. with a cable connected), the display LED 7 shows the recharging status as follows:

• Red solid: the battery is charging.

• Off: the battery is fully charged.

In this embodiment, a piezo-electric buzzer 17 is included as part of the sensor unit. This provides audible feedback and alerts to the user in different situations. Other appropriate audio/sounder devices could be used instead of a piezo-electric type.

In this embodiment, two eccentric rotating mass (ERM) vibration motors 18a, 18b are included as part of the sensor unit. These are configured to provide a physical vibrating sensation to the user in different situations, to compliment/augment/reinforce the buzzer 17 - that is, to act as an additional alerting mechanism for the user should they fail to hear the buzzer.

Sensor Unit Software

As outlined above, the operating software embedded in the microprocessor 13 controls all aspects of the electronic systems within the fall sensing unit. The software is configured so that the systems within the sensor are in “deep sleep” mode more than 90% of the time in order to preserve battery life. However, in this sleep mode the software also allows input and rapid auto-wake and reaction to an alarm situation, within a matter of microseconds. The other functions of the software are described below as part of the 'use' section.

Use

In this embodiment, and as outlined above, the fall sensing unit 2 is intended to be worn on a belt 3 or body harness 3, or similar. It is preferred that the fall sensing unit 2 is located on the belt (i.e. close to the hip of a user), or around the user's waist or hip area. However, it should be noted that it can be attached to any belt or harness strap suitably located in this area.

For normal (non-distressed) body motions, the waist/hip/general mid-body area is preferred as this area of the body has the least overall movement, and the least erratic movement. In contrast, if the fall sensing unit were positioned on the wrist or ankle of a user, there is the possibility of larger and more erratic movements, which would make it more difficult to detect and differentiate genuine falls from 'false positives' such as for example waving, throwing, a low-level/safe jump, using a hammer tool, or similar. In normal use, the fall sensing unit 2 operates in a 'passive' mode, with no output.

When freefall is detected by the accelerometer 12 (e.g. a worker falling from a roof or similar), this is sent to the microprocessor 13, which will receive the input, and will time the length of the freefall. If the freefall event lasts less than 20 milliseconds, then the microprocessor 13 will not record this as a fall event. If the freefall detection is over this time limit, then the microprocessor 13 will register this period as someone falling and trigger an alarm. This short delay is required to accurately determine whether the person is actually falling, or just stepping, walking, running, skipping or intentionally jumping from a low level.

In use, the fall sensing unit 2 constantly “listens” for a signal that indicates freefall is occurring or has occurred. That is, that the accelerometer detects a force of approximately 0~1g force, and that this event lasts at least 20 milliseconds. If both conditions are met, the fall sensing unit 2 recognises the situation as a genuine fall event and immediately raises/transmits an alarm signal.

The fall sensing unit 2 can detect a fall event if freefall occurs over a short distance/height - approximately as low as 500mm. One benefit of this is that the fall sensing unit 2 will positively detect and transmit a fall signal before it hits the ground, and before the device suffers an impact that can destroy the device and render it inoperable thereafter.

The fall sensing unit 2 can also detect impact. However, this is secondary, in that impact will only generate an alarm signal if the device has already detected a suitable freefall situation. In a genuine freefall situation the fall sensing unit 2 can typically transmit an alarm signal before it reaches the ground. This impact detection can act as a 'backup': If for example a fall is detected, but the fall by itself fails to generate an alarm, then the subsequent impact will generate an alarm.

When an alarm is triggered, the microprocessor sends instructions to the communication module 14 to wirelessly transmit an alarm to the fall sensing unit network, as outlined below.

Fall Sensing System

As outlined above, the overall fall sensing system 1 is formed by networking a number of separate items, the main item(s) in the network comprising separate/individual fall sensing units 2.

Network via integral wireless

In use, a number of the individual fall sensing units 2 are interconnected to form a network, the fall sensing system 1 formed from two or more fall sensing units 2. All users in the network wear a fall sensing unit 2, with the individual units wirelessly connected together to form a closed communication group/network. The size of the group/network can be adjusted as required - that is, any number of individual fall sensing units from two or more can be connected together. This is shown schematically in figure 5, with fall sensing units being added or removed shown at the top and bottom of the figure, and all of the fall sensing units within the network communicating with the other units within the network.

If a worker falls from height, their fall sensing unit 2 detects this event and transmits an alarm to the sensor unit network - that is, to all the other connected sensor units within the network (those worn by their colleagues). The transmitted alarm signal is detected by the communications module 14 in the other sensors in the network and transmitted within the receiving sensor unit(s) to their microprocessor 13. The microprocessor 13 in the receiving unit(s) then switches the sensor unit to an 'alarm' or 'alert' mode, activating the buzzer 17 and the motors 18a, 18b to provide an audio alarm, and a vibration alarm. All the other workers wearing networked fall sensing units 2 will therefore immediately know that one of their colleagues has had a fall accident at the work site, and that they must attend to them and get emergency assistance to the work site as required.

The purpose of connecting/grouping the sensor units into a closed network is to prevent confusion where there is more than a single group of workers all using the system at the same site, each from different organisations (e.g. roofers and scaffolders). A unit or group of units may have pre-set contact contacts/protocols specific to that group.

To join or form a network, a user firstly turns their sensor unit on using the on/off slide switch 6. The status LED 7 will immediately illuminate purple for between 1 and 5 seconds while the sensor unit initialises.

If the sensor unit is already part of a group/network of other sensor units, the system becomes active immediately after initialisation.

If the sensor unit is not already part of a group, a user can form a new group as follows: two of the fall sensing units 2 - a first unit and a second unit - are placed in close proximity. Once both sensor units have been turned on and initialised, a user presses and holds the connect button 10 on the first sensor unit for a few seconds. Once this first sensor unit is connected to the second sensor unit, it will beep twice to confirm that connection has been made, and the depressed button can be released. The two sensor units now form a group or network, and can “communicate” with each other over long and short range distance as required. What happens during this connecting process is that the first sensor unit wirelessly transmits a general polling signal that is recognised by the nearby second sensor unit, and in response the second sensor unit then wirelessly transmits a general polling signal which is recognised by the first sensor unit. These polling signals include the unique identifier or serial number from each sensor unit. As the connect button on the first sensor unit was pressed, this indicates that the first sensor unit wishes to connect with the second sensor unit, and the first sensor does this automatically, by copying the second sensor’s unique serial number into it's temporary flash memory, forming a secure ZigBee wireless mesh network between the first and second sensors. The first sensor effectively becomes a clone of the second sensor. The first sensor’s original serial number is never overwritten.

Once a group has been formed - an existing group - then further sensor units can be added to this as required. A third (or fourth, or fifth, etc) sensor unit 2 is placed in close proximity to any other sensor unit that is already connected/grouped (e.g. the first or second sensor units). A user presses and holds the connect button 10 on the third (or fourth or fifth) sensor unit for a few seconds. Once this sensor unit is connected to the already-networked sensor unit, it will beep twice to confirm that connection has been made, and the depressed button can be released. This sensor now forms part of the networked group. The group is expanded in this way. There is no limit to the number of sensors that can be connected together into a network.

As noted above, connection is achieved by the first or connecting sensor unit wirelessly copying the second sensor's unique identifier (in this embodiment a unique serial number in the microprocessor 13) into its temporary flash memory, forming a secure ZigBee wireless mesh network between the two sensors. The first sensor unit effectively becomes a clone of the second sensor unit. The original serial number of the first sensor unit is never overwritten, but the copied serial number of the first sensor unit is used in preference or priority.

If a user wants to disconnect a sensor unit from a group/network, they press the connect button 10 twice in quick succession. This input is received by the microprocessor 13, which will disconnect the sensor unit from the network. The sensor unit will beep once to confirm that the unit has been disconnected. Internally, the sensor software in the microprocessor 13 deletes the last copied serial number from its temporary flash memory, and the sensor unit reverts back to its default unique serial number again. The sensor unit can now no longer be recognised by the group it was previously connected to.

Each sensor unit may also be configured so that a user can tap or hit their sensor unit in a certain pattern to trigger a general SOS alarm from that sensor unit to the sensor units that form the rest of the group. In this embodiment, two taps in quick succession will activate the general SOS alarm, with the accelerometer 12 detecting the taps and the microprocessor 13 software recognising the two taps in quick succession, and triggering the alarm in response.

All the sensor units within a network send and receive. So when any sensor unit raises and sends an alert signal, all other connected/networked sensors receive the alert signal and react accordingly. Every sensor unit within the network actively listens for alert signals, while at the same time monitoring it’s own fall status and being ready to transmit an alert signal within the network if/when needed.

Network via app

A single sensor unit or a group/network of sensor units can also be connected via Bluetooth Low Energy (BLE) to one or more compatible smartphones, tablets, or other similar mobile devices 25 running a dedicated app designed to work with the fall sensing system, so that the sensor units 2 and also the smartphone(s), tablet(s), or other similar device(s) form the fall sensing system 1. This can help to ensure a more robust/reliable response when an emergency is detected at the work site. This arrangement is shown schematically in figure 6, which shows a number of networked fall sensor units, each of which can have a mobile device associated with and linked to the unit.

A user downloads and installs the app on their device. The app acts as a central hub for the system. The primary purpose of the app is to use the smart device to send an emergency SMS text message to one or more pre-set off-site contacts as soon as an emergency fall or SOS event is detected at the work site via the sensor unit(s). The message is issued for the purpose of alerting recipients to the occurrence of an accident at the work site and asking them to arrange for emergency assistance to be sent to the work site immediately.

The key features and operation of the app are detailed below.

A device running the app can be connected to a single sensor unit, or a group of connected sensor units, at any time, as follows:

When the app is first started or opened after installation, it will automatically attempt to connect with any nearby sensor unit via Bluetooth. A fifteen-second window is programmed into the app to allow this connection process to take place.

The app will display an animated on-screen icon to indicate what is happening to a user. The user should place a sensor - e.g. a first sensor - closely against the front or back face of the device on which the app is loaded, then hold down the “connect” button on the sensor unit for a few seconds or until the app displays confirmation that successful wireless Bluetooth connection has been made between the sensor and the device running the app. The sensor unit will also beep twice to confirm the connection. During this connecting process, the app wirelessly copies the first sensor’s serial number into its memory, forming a secure Bluetooth wireless network between them.

A confirmation or failure message is shown on expiry of this period. If no connection is made within approximately fifteen seconds, the app will invite the user to try again, or to cancel/close app. The app cannot be used if it fails to connect to a sensor.

Once the app has started, and connection to a sensor unit has been made, various information such as the name of the group can be inputted or changed via the app running on the smart device. Other information such as the work site address, GPS co-ordinates, and similar can be inputted (the app will automatically retrieve the GPS co-ordinates from the GPS system of the device if feasible). This ensures that any emergency response team or unit is routed to the correct destination in the event of an accident. A user will be prompted to confirm or change details such as current username and work site address. The app is configured so that a user has to positively confirm the details, as the system relies on these details in case of emergency. Once the user confirms these details, the app will then automatically get/save the GPS coordinates for the site, and confirm once this is completed. If it is not possible to get GPS coordinates, the app will confirm this.

If the single sensor unit to which the app is connected is part of a network of sensors, then an emergency signal from any of them will get sent to the app via the single “gateway” sensor unit or hub sensor unit that is connected to this app. However, it should be noted that other sensor units in the group can be connected to other separate apps/devices. Therefore in a networked group of sensors either one app/device can act as the hub for the whole group, or two or more, or all of the sensor units in the group can be connected to or paired with their own app/device (this has the advantage that there are multiple gateway units available to send emergency SMS off-site). In the latter example if any sensor unit in the group detects a fall for example, all the other sensor units will receive the alert, and all the connected apps will transmit the alert to their own pre-set off-site contacts. This has the advantage of increasing the chance of someone responding to the alert quickly.

Lone workers just require one sensor and one app/device for their system to work. An example of this arrangement is shown schematically in figure 7.

At any time, a user can access the app to change the saved details (e.g. because they have moved to a new site).

In this embodiment, the app allows the user to select which of two emergency contact options to use:

1. send an emergency message to up to three off-site mobile phones. These are pre-programmed contacts - e.g. friends or family members, or off-site work colleagues/managers/supervisors.

2. send an emergency message to a pre-set professional off-site/remote alarm monitoring centre that guarantees an emergency response at any time of day.

The contact numbers can be edited via the main app screen.

The app is further configured so that the emergency message can be cancelled, should this be required. As soon as a fall event has been detected and is showing on the smart device via the app, a ten-second countdown will show on the screen, with a 'cancel' option for sending the message shown. As soon as the timer expires the message will be automatically sent to the pre-set off-site contact or contacts.

The app is configured with an SOS button on the home page. This enables a user to manually trigger an emergency response if needed for any reason (for example, if someone is hurt due to an accident other than a fall from height, so the sensor unit has not activated). Once triggered, the app will perform in a similar manner to a fall event by sending an emergency message to pre-set off-site emergency contacts.

When configured as a hub (i.e. when the device/app is connected to a sensor unit, and the sensor unit is networked with other sensor units), the smart device with the installed app will immediately change from a watching state to an alerting state as soon as it 'hears' an alert signal from it's connected/paired sensor unit, which can come from the connected unit directly, or from any other sensor unit in the group. In the alerting state the app is configured so that the smart device boldly displays a flashing red emergency screen, and plays a sound file in a loop, such as for example a speech loop stating 'Emergency Fall Alert', or 'Emergency', or similar. The tensecond countdown timer is also displayed, giving an operator the opportunity to cancel the alarm.

It is most preferred that in use, the app is installed on the smartphones or similar smart devices of all the nominated off-site contacts intended to receive the alert message, as this will maximise the impact and efficacy of the system. On receipt of an alert, the app triggers the device to boldly display a flashing red emergency screen, and plays a sound file with a speech loop such as 'Emergency Fall Alert' or 'Emergency' or similar. These remote apps can also be configured with a 'stop alarm and get details' button or similar, which when pressed leads them to full details of the emergency (username, accident/work site address, GPS coordinates, fall event or general emergency, etc), and a mechanism by which this information can be recalled at a later date if needed.

If the nominated off site contacts haven’t installed the app, but their device is one of those listed to receive the alert, then they will receive the details in the form of a standard message (e.g. an SMS message or similar).

A device with the app installed can be added to a group of already-connected sensor units at any time, as follows:

A user selects any sensor unit in the group, and ensures that it has been turned on and that initialisation is successfully completed (the purple LED illuminates and then turns off, in the manner outlined above). The user then opens/launches the app.

The app will immediately attempt to connect to a nearby sensor, for a period of approximately fifteen seconds, displaying an animated on-screen icon so as to instruct the user as to what is occurring. A user places the selected sensor unit in close proximity to or touching the smartphone front or back face, then holds down the connect button 10 on the sensor unit until the app displays confirmation that successful wireless Bluetooth connection has been made between the two. The sensor unit will also beep twice to confirm the connection. If no connection was made, the app will invite the user to try again, or will cancel. During this connecting process, the app wirelessly copies the sensor unit's serial number into its memory, forming a secure Bluetooth wireless network between the smart device with the app loaded and operational, and the sensor unit.

The sensor unit then becomes a gateway or hub through which any alert signal detected within a networked group of sensor units (of which this sensor unit is a part) is sent. The alert signal is sent via the app to the off-site contacts.

In a lone-worker situation, the user can connect his sensor unit to the app in the same way as described above. The sensor unit and app will then communicate with each other via Bluetooth over a relatively short distance/range.

If a user wishes to disconnect a sensor unit from the app, they press the sensor’s connect button 10 twice in quick succession. The sensor unit beeps once to confirm.

In use, all the sensor units in a pre-set group are constantly 'listening' for an emergency signal, which can be generated either by the sensor unit itself, or by any other sensor or sensors in the group. This is achieved via the internal wifi transceiver that forms part of the communication module 14. If an app is connected to the group, then the app too is constantly listening for an emergency signal from the connected gateway/hub sensor unit. If that sensor unit hears an alert signal from any other sensor unit in the network to which it is connected, or from itself, then the sensor unit channels that alert to it's connected app.

As soon as a critical fall event is detected, the detecting sensor unit transmits a signal via wifi to all the other connected sensor units in the group. Each sensor unit will then sound a local alarm with vibrating motion (from the vibration motors 18a, 18b) and a buzzer sound (via the buzzer 17) to attract a user’s attention that a fall event has occurred.

If an app is connected, then the hub sensor unit will transmit an emergency signal to the app via Bluetooth, whereupon the app on the associated smart device will display a red flashing emergency screen, and may vibrate and play sounds, such as a vocal “Emergency Fall Alert” message, in a loop. The app will instruct the smart device to send an emergency message to all the pre-set emergency off-site contacts (max 3 contacts), or just to the remote monitoring centre, once the tensecond countdown timer has expired. The timer allows the alarm to be cancelled before the message is sent, in event of a false alarm. As soon as the timer has expired the alarm/message will be sent.

If the app is installed on the smart devices of the nominated off-site contacts, their device will receive the signal, and will display a red screen with a flashing “emergency” text, vibrate, and play an audio alert. The off-site contact can access the app to stop the alarm, and get details (e.g. the group username, the work site coordinates and address, and details of the emergency, as available).

If the nominated off-site contacts have not installed the app, they will receive basic details in the form of a standard SMS message. The message will include all key details of the incident, but without the presentational/formatting advantages provided by using the app - such as red screen, continuous audio loop, clear information layout, info recall etc.

The app has a remote monitoring mode, where details can be sent to a dedicated and specifically-configured emergency monitoring centre. If this remote monitoring mode is 'on', and a centre has been pre-chosen, then the app will send the accident details (username, accident/work site address, GPS coordinates, fall event or general emergency) in a specific SMS text format suited to the automated systems these centres require. When the remote monitoring mode is ‘on’, the app will only send emergency details to the remote monitoring centre and not the other off-site contacts.

The SOS function is only available where the app is installed and used. In the event of any accident not detected by the sensor, then a user can press the 'SOS' button on the default home screen of the app to trigger an alarm. All connected sensor units in the network will activate and go to an alarm mode as outlined above. In addition, the smartphone hub boldly displays a red screen with flashing 'emergency' text, vibrates and plays a sound file such as 'emergency' or similar in a loop. The app also automatically sends one emergency SMS message to all pre-set emergency off site contacts, or to the remote monitoring centre, once the 10 second countdown timer has expired.

A fall sensing system as described above is specifically configured to detect freefall followed by impact. The accelerometer algorithm parameters, filters, timing delays and sensitivity settings are best suited to detect fall and impact motion.

The battery power and charging system is small, lightweight and low cost, and has high capacity for longest product up-time without frequent recharging. A unique deep sleep and auto-wake routing was built into the system software to further achieve this, together with the hardware and software to recharge the batteries.

The fall sensing system of the present invention, as described in the specific embodiment above, detects two main types of motion: freefall at approximately 0-1G force firstly, followed by impact. The sensor software in the microprocessor is configured to receive a signal indicative of freefall, and to time this. If the event exceeds a time of 20 milliseconds, this is registered as a fall event, and the software triggers an alarm. This delay period helps to accurately determine whether the person is actually falling, or just stepping, walking, running, skipping or intentionally jumping from a low level height. This helps prevent false alarms. As outlined above, if the fall event is followed by detection of an impact event, then this can act as a 'back-up' for detection and transmission of an alarm.

The sensor units can be wirelessly connected and disconnected, using a simple procedure and mechanism (via the connect button) that copies/duplicates the serial numbers to clone the sensor units, to form a flexible and scaleable closed network. The closed network does not allow sensors that have not joined the network to participate in that network. This is useful where there are multiple independent teams of workers (e.g. roofers and scaffolders) on one site, where each team will have their own emergency response protocols. If a sensor unit moves out of wireless range of the rest of the group and then re-enters the range, or if a sensor unit is turned off and then on, the sensor unit will automatically rejoin the group (assuming the details of the group have not been changed). This is important as it allows a user to temporarily leave the work site and return later, and they will want their sensor to rejoin the network easily.

A smart device running the app can be wirelessly (via Bluetooth) added into the wifinetworked sensors, which allows the use of features such as sending alert messages to off-site or remote locations or personnel.

The sensor units can also be used independently if required - i.e. by lone workers.

In an alternative form to that described above, the sensor units can be connected using a code switch 19, an example of which is shown in figure 4 and in the schematic of figure 3b. This type of switch comprises a series of smaller switches that a user physically slides between on/off states, to set a unique code. In order to connect to form a group, all of the sensor units of this alternative form would be required to have their code switches 19 physically set to the same number/pattern. The code switch 19 is user-accessible from the exterior of the housing 21 in this alternative embodiment. It should also be noted that the batteries could be internal non-accessible rechargeable batteries, or regular batteries that require user access for replacement, by way of an opening with a cover or similar.

Claims (33)

Claims

1. A fall sensing unit, comprising:

a sensing means configured to detect motion indicative of freefall and motion indicative of impact;

a communication means configured to transmit signals wirelessly;

a processing means configured to receive and assess input from the sensing means and to output an alarm signal via the communication means if the assessed input indicates that a fall event has occurred.

2. A fall sensing unit as claimed in claim 1 wherein the sensing means comprises an accelerometer.

3. A fall sensing unit as claimed in claim 2 wherein the accelerometer comprises a three-axis digital accelerometer.

4. A fall sensing unit as claimed in any one of claims 1 to 3 wherein the processing means comprises a microprocessor.

5. A fall sensing unit as claimed in claim 4 wherein the microprocessor is configured to record that a fall has occurred if freefall motion lasts at least 20 milliseconds.

6. A fall sensing unit as claimed in any one of claims 1 to 5 wherein the communication means comprises RF transceiver modules configured for short, mid and long range wireless communication.

7. A fall sensing unit as claimed in claim 6 wherein the RF transceiver modules comprise an RF transceiver module configured as a short/long range transceiver, and a dedicated short/mid range RF transceiver module.

8. A fall sensing unit as claimed in claim 7 wherein the short/long range transceiver comprises an RF transceiver module configured to operate in the range 2.4052.475GHz of the ISM band.

9. A fall sensing unit as claimed in claim 7 or claim 8 wherein the short/mid range RF transceiver module is configured to operate in the range 2.402-2.480GHz of the ISM band.

10. A fall sensing unit as claimed in claim 9 wherein the short/mid range RF transceiver module comprises a Bluetooth module.

11. A fall sensing unit as claimed in any one of claims 1 to 5 wherein the communication means comprises a wireless communication module.

12. A fall sensing unit as claimed in any one of claims 1 to 11 further comprising an audio alert means, configured to activate on receiving the alarm signal.

13. A fall sensing unit as claimed in claim 12 wherein the audio alert means comprises a piezo-electric buzzer.

14. A fall sensing unit as claimed in any one of claims 1 to 13 further comprising a vibrating means, configured to activate on receiving the alarm signal.

15. A fall sensing unit as claimed in claim 14 wherein the vibrating means comprises at least one eccentric rotating mass motor.

16. A fall sensing unit as claimed in any one of claims 1 to 15 further comprising a housing configured to surround and contain the sensing means, communication means and processing means, and; a means for securing the housing in position on a belt or harness.

17. A fall sensing unit as claimed in claim 16 wherein the means for securing the housing in position comprises a flap connected to and extending from the housing to wrap around and hold the fall sensing unit in position on a belt or harness.

18. A fall sensing unit as claimed in claim 17 further comprising one or more of: an on/off means; a device status indicator; a connection/disconnection means; a means to connect a battery charger, all located for viewing and/or access from the exterior of the housing.

19. A fall sensing unit as claimed in claim 18 wherein the on/off means comprises a switch; the device status indicator comprises a display LED; the connection/disconnection means comprises a connect button; and; the means to connect a battery charger comprises a USB socket.

20. A fall sensing unit as claimed in claim 18 wherein the flap and housing are configured so that the on/off switch, display LED, connect button, and USB socket are user visible and/or user accessible in use.

21. A fall sensing unit as claimed in any one of claims 1 to 20 wherein the processing means is further configured to output an alarm signal via the communication means if two taps are detected in quick succession.

22. A fall sensing system, comprising:

two or more fall sensing units as claimed in any one of claims 1 to 21;

the fall sensing units configured so that the communication means can transmit and receive information between units to allow a closed group network to be formed from the units.

23. A fall sensing system as claimed in claim 22 wherein, once a closed group network has been formed, the alarm signal transmitted in the event of any single fall sensing unit detecting a fall event will be transmitted to each fall sensing unit within the network.

24. A fall sensing system as claimed in claim 22 or claim 23 wherein the transmitted and received information comprises the unique serial number of the transmitting fall sensing unit.

25. A fall sensing system as claimed in claim 23 wherein the receiving unit is configured to copy the unique serial number to become a copy of the transmitting unit.

26. A fall sensing system as claimed in any one of claims 22 to 25 wherein the fall sensing unit is further configured so that a user can disconnect the unit from the network.

27. A fall sensing system, comprising:

at least one fall sensing unit as claimed in any one of claims 1 to 21;

a mobile device;

the mobile device and one of the at least one fall sensing units mutually configured so that information can be transmitted and received between the one fall sensing unit and the mobile device, and between the fall sensing units, to allow a closed group network to be formed;

the mobile device further configured to transmit an emergency message on receiving an alarm signal from the one fall sensing unit.

28. A fall sensing system as claimed in claim 27 wherein, once a closed group network has been formed using multiple fall sensing units, the alarm signal transmitted in the event of any single fall sensing unit detecting a fall event will be transmitted to each fall sensing unit within the network.

29. A fall sensing system as claimed in claim 27 or claim 28 wherein the transmitted and received information comprises the unique serial number of the transmitting fall sensing unit.

30. A fall sensing system as claimed in claim 29 wherein the mobile device is

5 configured to copy the unique serial number of the one fall sensing unit.

31. A fall sensing system as claimed in any one of claims 27 to 30 wherein the fall sensing unit is further configured so that a user can disconnect a fall sensing unit from a network.

32. A fall sensing system as claimed in any one of claims 27 to 31 wherein the

10 mobile device is configured to transmit the emergency message as an SMS text message.

33. A fall sensing system as claimed in any one of claims 27 to 32 wherein the fall sensing unit is further configured so that any other fall sensing unit within a previously-formed network that is not already connected to a mobile device can be

15 connected to another mobile device.