WO2020183189A1

WO2020183189A1 - A modular sensor system

Info

Publication number: WO2020183189A1
Application number: PCT/GB2020/050636
Authority: WO
Inventors: Leon Williams; Justyna KALETA; Maurizio Bevilacqua
Original assignee: Cranfield University
Priority date: 2019-03-14
Filing date: 2020-03-13
Publication date: 2020-09-17
Also published as: GB2582297B; GB2582297A; GB201903464D0

Abstract

A module (20) for use in a modular sensor system, e.g. as could be deployed in a waste water treatment plant. Each module has a weatherproof housing (21, 34), a battery (36), a solar cell (22), a wireless communication device (24), a processor (28) and a port for a sensor device to connect. In use, the solar cell provides power to charge the battery for the module to be self-sufficient while the processor is configured to manage power output directed to the sensor device dependent on its type. Sensor data is communicated via the communication device to a hub for further processing and monitoring purposes.

Description

A Modular Sensor System

The present invention relates to a modular sensor system and a module suitable for use in such a system. The module acts as part of a communication platform enabling data to be collected from sensors (plugged into or integrated with the module) for subsequent process control and/or monitoring.

Background to the invention

Remote sensor devices and systems for their implementation are known. For example, a water treatment plant may have a network of sensor units for measuring data to collect for transmission to a central station where various parameters are monitored. However, typically each sensor is a specialised unit and must be individually programmed and calibrated for its required task during installation in order to be an effective part of the monitoring network.

Summary of the invention

The present invention seeks to propose a modular sensor system. Particularly, an objective is to supply a plug and play, interchangeable element/module as a sensor platform which is simple to set up and deploy in the field, e.g. with minimal skill. By virtue of its construction the module should be suited for outdoor use in a variety of challenging environments.

In at least the field of water, sanitation and health (WASH) there is a need to measure technology performance during solid/liquid processing to ensure consistency, reliability and safety, whilst simultaneously constraining energy utilisation. To date, there is only limited development of either sensors or sensory platforms (i.e. processors) across this field and no platforms currently available that can facilitate whole system performance management from 'the user through to environmental discharge'. The present invention therefore seeks to demonstrate an engineered cloud based platform comprising a broad sensoring architecture capable of measurement and assimilation of both human user and process technology performance to enable responsive, and real-time, whole system process control.

A modular sensor system/network according to the invention is intended to provide a simple to deploy and operate platform or, at the least, provide the public with a useful alternative to available choices. The inventive concept was not heretofore possible through available devices because each separate module required its own bespoke programming to suit it for purpose and an overall monitoring system needed to be created to combine sensor inputs.

A module, ultimately for use in a sensor system, is provided according to a broad aspect of the invention outlined by claim 1. A general system of implantation for a plurality of modules is outlined according to claim 16. Further features of the device and system/method associated by a common inventive concept are outlined by the dependent claims.

In general a module according to the invention is a device designed to be deployed in a particular location while capturing and storing energy to power its sensing function. Each module may have GPS capabilities such that, although fixed to a device, technology, equipment, or building, it can also be attached to a moving vehicle (e.g. truck carrying sanitation waste). Such a device, in the form of a cuboid housing, can then be used to provide/relay data to a point of collection/monitoring where the data is analysed for the purposes of decision making and optimising function of the system being monitored. The invention can be further considered an analytics sensor test-kit for advanced process control. In one form the module comprises a weatherproof housing (e.g. a robust plastic moulding in two parts), an energy storage device (e.g. a battery), an optional an energy harvesting device (e.g. a PV panel to trickle charge the battery), a communication device (e.g. a wireless transceiver/radio module to send and receive data), a processor; and a sensor device and/or a port for attachment to a sensor device. In operation the processor manages power directed to the sensor device (e.g. probes wired to the module via the port) dependent on its type (e.g., but not limited to, pH, temperature, voltage, current, pressure, microbial, humidity or flowrate sensors) and communicates data associated with the sensor device, e.g. to a hub or other processing location.

The means of energy harvesting may comprise devices/systems that derive energy where appropriate from the Sun, induction, thermal differentials, kinetic movement, static electricity, the piezoelectric effect, radio waves, light, sound and/or other forms of background radiation.

Alternatively or in addition, the module may be charged via a USB port or the like. New means may be discovered in the future that are also compatible with the inventive concept described herein.

Brief description of the drawings

Figure 1 illustrates a general view of components according to one example of module; Figure 2 illustrates an assembled view of two sub-modules, from the components shown in Figure 1;

Figure 3 illustrates orthographic views of an assembled module;

Figure 4 illustrates a general view of components according to a second example of module; Figure 5 illustrates an assembled view of components from the example of Figure 4;

Figure 6 illustrates a view of two sub-modules, ready for use;

Figure 7 illustrates an underneath view of a module where a mounting mechanism is visible for securing the module to a fixed structure.

Detailed description of the invention

The following description presents exemplary embodiments and, together with the drawings, serves to explain principles of the present invention. Flowever, the scope of the invention is not intended to be limited to the precise details of the embodiments, with variations apparent to a skilled person deemed also to be covered by the description. Terms for components used herein should be given a broad interpretation that also encompasses equivalent functions and features. Descriptive terms should also be given the broadest possible interpretation; e.g. the term "comprising" as used in this specification means "consisting at least in part of" such that interpreting each statement in this specification 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.

The present description refers to embodiments with particular combinations of features, however, it is envisaged that further combinations and cross-combinations of compatible features between embodiments will be possible. Indeed, isolated features may function independently from other features and not necessarily be implemented as a complete combination.

In general, the invention relates to a module that provides a platform to receive input from a sensing means. A plurality of such modules are deployed in an overall monitoring system and communicate with each other and/or an associated hub or wider network in order to process and act on data.

A particular form of module for use in a system according to the invention takes on the appearance of a small cube (e.g. 2.5 cm³). Such a cube may include a weatherproof housing, an energy storage device, an energy harvesting device, a communication device, a processor; and a sensor device but more likely a port for attachment by a wired connection to a sensor device located outside the housing. The cube preferably serves as an automated analytics platform, e.g. for the WASH (Water and Sanitation for Health) community.

In terms of general function of the cube, where an energy harvesting device is present this is configured to provide power to charge the energy storage device (which may alternatively be mains powered or through another suitable power supply system) and the processor is configured to manage power directed to the sensor device dependent on its type and communicate data associated with the sensor device via the communication device.

Figure 1 illustrates an exploded view of example components for a module implementable in a system according to the invention. Particular components include: a first cover (1) for

accommodating the radio module components, an SMT (surface mount technology) module with PCB antenna (2), a radio module PCB (3), a first modular contact (4) (e.g. Bourns male four way), radio module enclosure (5). The first cover 1 is fixed to the radio module enclosure 5 by screws 6, effectively providing an assembled radio module unit which is a "first half" of the overall sensor module.

Components that comprise the "second half" sensor unit include a main enclosure (7), a second modular contact (8) (e.g. Bourns female four way) which is extendable through an opening in the enclosure (7) in order to contact with the first modular contact (4). A sensor PCB (9) communicates, via the modular contacts (4/8), with the radio module (3) and sensor components, e.g. an SMT grounding contact (10) (supplied by Harwin) and hall effect sensor (11) (supplied by Honeywell).

A battery holder (12) and associated contact (13) is enclosed by a second cover (14) that slots into enclosure (7) to be secured by screws as illustrated. In use a coin cell battery (15) supported by holder (12) energises components requiring electrical power to operate.

Figures 2 and 3 illustrate semi- and fully- assembled views respectively of the module. Particularly Figure 2 shows the assembled radio module within enclosure 5, ready to be coupled to the main sensor enclosure 7 which, in practice, is intended to activate the module for use when clipped together as contacts 4 and 8 mate.

The illustrated module includes components required for connection to a sensor device and subsequent collecting of data for communication via the radio module. It does not illustrate an energy harvesting device, e.g. a solar cell which could be located upon the first cover 1 for supplying electrical energy to the components and/or trickle charge the battery.

An example of communication devices includes commercially available wireless radio modules based on the 802.15.4 standards (issued by the Institute of Electrical and Electronics Engineers (IEEE). All sensor devices supplied with the kit will have their associated radio module assigned with a secure network ID and password.

The modules may be interchangeable and modular in design as, by way of example, they each feature six analog in/out pins and one universal synchronous receiver/transmitter (UART) interface. Extra flash memory capabilities may be added to the module depending on cloud upload frequency. For example, in the event that an analytics sensor module is unable to transmit data (i.e. data transmission failure due to a blocked signal) the sensor could be programmed to temporarily store data within its flash memory until a clear connection is re-established.

One example of communication module includes a Digi XBee^® S2C (Digi XBee is the brand name of a family of form factor compatible radio modules from Digi International) which presents multiple pins (one UART bus, one SPI bus, thirteen digital input/output (I/O) pins) that can read data from potential sensors. Out of thirteen (1/0) pins, four feature 8-bit analog to digital convertors (ADC) that can read up to 1.2v. 8 bit convertors have 1024 diff levels, meaning inputs can be read by increment of 1.172mv. Selected sensors will preferably take advantage of those buses and pins to minimise development time.

To ensure consistency across the data architecture and in reference to its shape, the module is often referred to herein as a "sensor cube". In operation, the cube consists of two interchangeable modules, e.g. a radio module and a sensor module. The radio module contains the Digi XBee^® whereas the sensor module contains (for example) a CR2032 3V coin cell battery and sensors/port. When the two half-housing modules are mechanically sealed together using a clipping system and gasket, the Digi XBee^® and the battery become electronically connected. This can be achieved through the linking of the circuit boards in each module using modular connectors. From then on, the complete module automatically starts sending sensor data to the gateway (hub/server) without further user intervention.

The circuit is to be devised in such way that the sensor itself will only be powered when the cube module is fully assembled (e.g. clipping two halves of the housing together), preserving battery life when on the shelf. In the context of the WASH community, sensors are primarily required to control/ measure eight parameters during the process, namely: pH, temperature, Methane (presence), sludge level, turbidity, voltage, current and water level. Accordingly, sensors are sourced for coupling to the module which have one or more of these capabilities.

Since the modules are intended to be relatively low cost units it is probable that each can be dedicated to one sensor input, however, modules can be designed with multiple sensor device input capability to process data from more than one sensor source. A further advantage of such an arrangement is sharing energy and data resources across multiple units, as opposed to overloading a few modules with multiple tasks.

The main aim of module design is to make the cube sensor capable of being self-sufficient, reliable, able to sense data through multiple interchangeable modules connected to the same main framework of power and have the ability to then transmit the collected data, e.g. through the cloud.

The main design in the development of the cubes is split into three sub-module sections: power module, sensor module and transmission module. Each sub-module sits one on top of the other, power being at the bottom and transmission being at the top.

The ability to have multiple sensors interchanged through the changing of different sensing modules can be achieved, provided the sensors adhere to the processor's input voltages, e.g of 0.2-1.5V for the XBee exemplified above.

Figures 4 to 7 illustrate a second example of module, generally denoted 20, for use with a system according to the invention. With reference to Figure 4, the module 20 may be comprised of: a transmitter casing 21; a solar panel/transmitter cover 22, serving as an energy harvesting device which in some forms may be detachable to be located away from the module; snap-fit clips 23; a transceiver antenna 24 and transceiver PCB 25, serving as a communication device supported by a transceiver holder 26; sensor casing cover 27; sensor PCB 28 which supports an electrical connector 29 for coupling to the underside of transceiver PCB 25 and an optional external power connection point 30 and sensor connection point 31. In principle the sensor port could be a wireless connection to a remote sensor device and should include this interpretation within its scope. Sensor PCB 28 performs a control processor function that manages power to the sensor device. It may also perform protective functions for an energy storage device and the communication device, as well as voltage step up or comparable functions for the energy harvesting device. At the base of module 20 is an energy storage device, e.g. re-chargeable lithium battery 32 seated on a mounting plate connector 33. A main sensor casing 34 is configured to receive the sensor casing cover 27 for fixing thereto, e.g. by screws 35, and provides an enclosure for the battery and sensing PCB. An opening 36 through the floor of sensor casing 34 enables a male mounting device (see Figure 7) to extend therethrough from underneath mounting plate connector 33, ultimately for locking the module to a mounting plate 37 that may be attached (e.g. through screw holes 38) to a fixed structure where the module is to be located.

Figure 5 illustrates an assembled module 20 primarily comprised of the transmitter sub-module 21 and sensor sub-module 34. Figure 6 shows these two components separable where the clips 23 enable either a permanent sealed connection between components or, more preferably, provision for removal of the transmitter sub-module for access to internal components of either sub-module.

A port 39 proximate the power source connection point 30 provides a solar panel/battery to battery wired connection such that a further solar panel or battery could be plugged in to meet additional energy requirements of a particularly draining sensor type.

Figure 7 illustrates details of a mounting mechanism to secure a module on a fixed structure or the like. Particularly, a male protrusion or key 40 extends from an underside of module 20 (e.g. through an opening 36 in casing 34) to be received by an opening 41 in mounting plate 37 fixed to a structure (not illustrated). In one form, once received into opening 41, module 20 may be turned a quarter turn to lock surface features of the key 40 into corresponding mating features about opening 41. Other suitable mounting mechanisms may be employed such as clips, bayonet, interference fit, tongue-in-groove or equivalent.

The housing components may be made from available materials (selected for durability, UV resistance, etc.) and by known production techniques such as injection moulding and/or 3D printing. Suitable electronic components can be sourced by those skilled in the art to construct a module according to the invention. Indeed components may also be integrated together in forms not presently illustrated; e.g. the communication device and processor may be integrated in a single board if allowed by prevailing technologies.

The module and/or sub-assemblies may be foam filled for additional weatherproofing and strength. Preferably the communication device incorporates a SIM card for identification over a mobile data network and at least 1km range for communication between modules and a wide network.

Preferably, the data set output is universal for compatibility with different applications and end uses. Data may be packaged for intermittent transmission or continuously broadcast. A data storage capability (e.g. flash memory) may provide temporary or permanent data storage, particularly to act as a buffer if transmission is interrupted so complete monitoring can be maintained.

The overreaching goal of the module is to provide a unit that is robust, not vulnerable to a hostile/outdoor environment with wireless power and in-built connectivity in order to relay data from the attached sensor(s).

To configure a module for operation it is intended that the communication sub-module and sensor sub-module be clipped together to activate power from the battery to the respective circuits. The sub-modules are effectively interchangeable components that can be swapped out if the other half is damaged. Furthermore, in some forms the sensor sub-module may be permanently configured for common sensor types to simply its componentry, therefore a radio sub-module can be connected to substitute sensor sub-modules.

A sensor device is then plugged into the sensor connection point 31. Power requirements for the sensor can be manually set (before the sub-modules are combined) or may be automatically detected by the processor 28. Detection/identification can be determined by a physical response (e.g. voltage requirement), behaviour pattern and/or user ratification (e.g. by a prompt on the display of a mobile device).

Upon the PCB 28 an array of fuses (not shown) may precisely control and adjust voltage inputs to the two sub-modules, thus allowing almost any sensor with its own specific voltage requirements to be incorporated into the overall framework. As mentioned, the fuses may be set manually (with an on/off switch), or automated to enable the fuses to be controlled via software.

Accordingly, according to one aspect different sensors with different voltage requirements can be interchanged in the main framework without modifying the overall cube structure; and the whole cube is protected from any power surges which may damage the sensors, thus ensuring that the device is robust and requires minimal external support during field use.

An implementation of a plurality of modules for real-world data monitoring, namely within a single household scale septage treatment system 50, is illustrated by Figure 8. Particularly, an array of modules 20 each includes a sensor probe 40 associated with an aspect of the treatment system. In practice waste water from a toilet 51 flows through pipe 52 toward a septic tank 53 where sediment settles out while liquid water proceeds to a reed bed 54. A reservoir 55 stores run-off from the reed bed (all gravity fed at this stage) before being pumped (stage 56) to an electro chemical cell 57 comprised of an anode and cathode chamber. Water 58 at the end of this process can be finally treated/disinfected for return to the toilet cistern or other uses.

The details of the treatment system will not be discussed herein, however, it will be clear that data can be collected from multiple points in the process by modules 20 according to the invention. Each module 20 is configured for wireless communication of the data it collects in order to monitor performance of the system.

Data from a module's sensor, in any use out in the field, is preferably communicated wirelessly directly to a hub or firstly by relay through another module, which may be necessary where communication from the first module is inhibited or cannot spare power for such a function. Indeed a module may be part of the monitoring network even if it has no sensor itself and merely acts as a relay, being configured to reroute power and/or data transmission functions between modules, e.g. where sensor device has high power requirements

Beyond the example application, the analytics cube and accompanying software has wider commercial exploitation potential with regards to gathering performance analytics of a wide range of water, sanitation and hygiene systems. For example, it could be used as a diagnostics product, a process control unit, an analytics resource, or a feedback loop for inventors to learn about the performance of their technology prototypes during field tests.

The system may be operated from a mobile telephone application with a front end graphical user interface (GUI). By way of example, when the user logs in to the mobile app with a required username and password, they will be presented with a home page listing all the sensor kits assigned to that user, e.g. on a map, along with the current status of kit. When a particular sensor kit is selected it will open a dashboard that lists all sensor data linked to that kit. It can also notify if any new sensor is added to the array.

A communication hub may be employed to handle traffic from the monitoring systems (sensor kits). By way of example, an Azure™ Internet of Things (loT) Hub is a cloud hosted managed service shown in the network diagram of Figure 9.

As illustrated, a central message hub 60 provides for bi-directional communication between an application executed by a portable device 61 and the collection of sensors 62 it manages. Preferably the loT hub is an open and flexible cloud platform that, as a service, which will allow management of an almost limitless number of devices.

Use of an existing hub platform will avoid having to design and maintain a separate database to receive device messages, while providing a secure communication channel for the devices to send data.

Per-device authentication enables each device to be connected and managed securely with complete control over device access. Administration of the loT hub can be controlled via a security group which allows external partners to be granted access to the portal.

The current proposed architecture of the solution includes having the devices registered to the Azure loT Hub and configured to send sensor data to the hub. An interface web application server can be configured to fetch data from the loT hub every three minutes (based on requirements, could be varied). Such an approach could potentially reduce costs due to a reduction in frequency of data reads from Azure. Finally, a mobile sensor app can connect directly to the interface server to feed data back to the end user via the app. Further functionality of the mobile application may include augmented reality to indicate sensor data in real time when a user is visiting a monitored site. For example, when on site at the treatment site indicated by Figure 8, a user can use a mobile phone's image capturing capabilities to view the physical/visible parts and superimpose icons and performance data (e.g. an icon of the settling tank and its operating parameters) onto the captured image.

Claims

Claims:

1. A module comprising:

a weatherproof housing;

an energy storage device;

a communication device;

a processor; and

a sensor device and/or a port for electrical connection to a sensor device;

wherein:

the processor is configured to manage power output directed to the sensor device dependent on its type and communicate data associated with the sensor device via the communication device.

2. The module of claim 1, further comprising an energy harvesting device configured to provide power to charge the energy storage device.

3. The module of claim 1 or 2, wherein the processor is configured to detect a type of sensor device by physical response and/or behaviour pattern for automatically managing power output to the sensor device.

4. The module of claim 1 or 2, wherein including a manual switch for managing power output to the sensor device.

5. The module of any preceding claim, wherein the communication device includes a wireless transceiver.

6. The module of any preceding claim, wherein the processor is reprogrammable.

7. The module of claim 2, wherein the energy harvesting device is a photovoltaic cell.

8. The module of any preceding claim, including a power/recharge port and/or a plurality of sensor ports.

9. The module of any preceding claim, wherein the communication device is housed in a first sub-assembly enclosure and the processor and sensor device and/or a port for electrical connection to a sensor device is housed in a second sub-assembly enclosure.

10. The module of claim 9, wherein each of the first and second sub-assembly provided with mating electrical connections for mutual connection together.

11. The module of claim 10, wherein the first and second sub-assembly are removably

connectable together by way of a clip, interference fit, or bayonet design.

12. The module of claim 10 or 11, wherein the module is electrically activated, energising the communication device and processor, by connection of the mating electrical connections.

13. The module of any preceding claim, wherein the communication device includes a SIM card, GPS capability and/or Bluetooth communication protocol capability.

14. The module of any preceding claim, wherein the communication device is configured for output of a universal dataset.

15. The module of any preceding claim, wherein the sensor device is selected from one or more of the following types, alone or in combination: pH, temperature, voltage, current, pressure, microbial, humidity or flowrate.

16. A modular sensor system comprising a plurality of modules according to claim 1, wherein each module is configured to communicate data therebetween, to a hub and/or to a wider communication network.

17. The modular sensor system according to claim 16, wherein the hub includes a computer processor configured to execute applications for data manipulation, analysis and graphical display.

18. The modular sensor system according to claim 16 or 17, configured to reroute power and/or data transmission functions between modules.

19. The modular sensor system according to any preceding claim 16 to 18, including a mobile device running an application with a graphical user interface operable by a user to access data collected from at least one module.

20. The modular sensor system according to claim 19, wherein the application is operable to configure modules for a particular sensor device type by affirming said sensor device type upon prompting.

21. The modular sensor system according to any preceding claim 16 to 20, wherein the processor of a module is provided with software and/or firmware to manage the communication device such that if a signal is obscured to the hub or wider communication network it redirects data transfer to a neighbouring module for onward transmission to the hub or wider communication network.