Vibration monitoring device

Abstract

A vibration monitoring device for measuring hand-arm vibration (HAV) and / or whole-body vibration (WBV) of an operator using vibration generating equipment, such as power tools, ride-on machinery or ve

Description

This invention relates to a vibration monitoring system and, in particular, to a vibration monitoring device of such a system. The disclosure also relates to a vibration 5 monitoring system for measuring Hand Arm Vibration (HAV) and / or Whole Body Vibration (WBV) exposure levels experienced by operators of equipment that generate vibrations in operation, such as powered hand tools and ride-on machinery / vehicles. The disclosure also relates to one of or combinations of a vibration monitoring device for measuring the vibrations, an equipment identification module for identifying the 10 equipment being used and a vibration logging device for receiving data indicative of the measured vibrations from one or more of the vibration monitoring devices. BACKGROUND 15 Systems exist to measure and protect operators and employees from excessive exposure to hand arm vibration (HAV) and whole body vibration (WBV) when using powered hand tools or ride on machinery / vehicles. However, challenges exist in terms of managing the power consumption of the 20 components of such systems, allowing for the use of communication protocols with desired functionality and avoiding incorrect identification of equipment. SUMMARY 25 According to a first aspect of the invention we provide a vibration monitoring device for measurement of one or both of hand arm vibration, HAV, and whole body vibration, WBV, of an operator using vibration generating equipment, the device comprising: a wake-up receiver configured to receive signalling including from at least one equipment identification module for identifying the equipment being used by the 30 operator, wherein the wake-up receiver is configured to detect a predetermined feature in said signalling indicative of the signalling originating from said equipment identification module and, in response to detection of said predetermined feature, provide a wake-up control signal to provide for activation, from a low-power state, of a further receiver for decoding said signalling; and 35 a sensor configured to measure vibration. In one or more examples, decoding comprises extraction of the information that identifies the equipment from said signalling. In one or more examples, detection of the predetermined feature does not comprise extraction of the information that identifies the equipment from said signalling. In one or more embodiments, said predetermined feature comprises one or more of: 5 a) a predetermined pulse width; b) a predetermined pattern of a plurality of pulses in said signalling; and c) a predetermined frequency. In one or more embodiments, said vibration monitoring device is configured such that 10 said wake-up control signal from the wake-up receiver is configured to provide for activation, from a low-power state, of circuitry configured to process an output of said sensor for measuring said vibration. It will be appreciated that the low-power state comprises a state of lower power 15 consumption than when in normal operation and may comprise a state in which the sensor circuitry is not provided with power or where power is actively restricted. In one or more embodiments, said vibration monitoring device is configured such that said wake-up control signal causes activation of the further receiver by causing power 20 to be provided to said further receiver. In one or more embodiments, said vibration monitoring device includes motionactivating circuitry configured to provide for activation, from a low-power state, of said wake-up receiver, based on detection of motion above a threshold level. 25 Thus, in one or more examples, in the absence of said motion, such as absence of said motion for a predetermined period of time, the wake-up receiver may be configured to enter the low-power state. 30 In one or more embodiments, said motion-activating circuitry is configured to detect said motion using said sensor. In one or more embodiments, said further receiver is, in response to having been activated by said wake-up control signal, configured to: 35 measure the received signal strength of said signalling; and wherein signalling having a received signal strength lower than a received signa! strength threshold is ignored by said further receiver and signalling having a received signal strength greater than a received signal strength threshold is decoded by said vibration monitoring device to extract identifying information from said signalling that identifies said at least one equipment identification module. This has been found to be advantageous because the further receiver can be 5 maintained in the low-power state until the predetermined feature is identified and then, with the additional functionality of the further receiver to measure signal strength, the received signal strength can be checked to provide an indication of whether the equipment identification module is sufficiently nearby for the vibration monitoring device to "pair" with it and begin a vibration measuring process. Otherwise, 10 the further receiver can return to the low-power state and the wake-up receiver can continue to determine the presence of the predetermined feature. In one or more embodiments, said wake-up receiver is configured to measure the received signal strength of said signalling, and the provision of the wake-up control 15 signal is further based on the signalling having a received signal strength greater than a received signal strength threshold. In one or more embodiments, said vibration monitoring device includes a first switch configured to route said signalling to said wake-up receiver until said wake-up control 20 signal is provided whereupon said first switch is configured to route said signalling to the further receiver. In one or more embodiments, said vibration monitoring device comprises: an antenna terminal for coupling to an antenna for receiving said signalling and 25 transmitting messages; and at least two different signal paths between the further receiver and the antenna terminal comprising a first signal path and a second signal path, wherein: said vibration monitoring device is configured to route signalling from the antenna terminal to the further receiver via said first signal path; and 30 said vibration monitoring device is configured to route signalling from a transmitter of the vibration monitoring device to the antenna terminal via the second signal path; and wherein one or both of (a) said first signal path includes a greater level of attenuation than said second signal path and (b) said first signal path includes a lower 35 level of signa! amplification than said second signal path. In one or more embodiments, the vibration monitoring device is configured to decode said signalling to extract identifying information from said signalling that identifies said at least one equipment identification module and measure, using said sensor, the HAV or WBV of an operator determined to be generated by the vibration generating equipment identified by the identifying information from the at least one equipment identification module. 5 In one or more examples, the vibration monitoring device comprises a processor configured to perform said decoding based on the signalling received by the further receiver. In one or more embodiments, said measuring of the HAV / WBV continues at least until 10 said vibration monitoring device determines that said identifying information is no longer present in the signalling. In one or more embodiments, said measuring of the vibration continues at least until said vibration monitoring device determines that said identifying information is no 15 longer present in the signalling and, in response to determining that the identifying information is no longer present in the signalling, generate a vibration exposure message including said measured vibration and said identifying information for transmission to a vibration logging device. 20 In one or more embodiments, the vibration monitoring device is battery powered. According to a further aspect of the invention we provide a combination of the vibration monitoring device according to the first aspect and at least one equipment identification module, the equipment identification module configured to be coupled to a respective 25 vibration generating equipment and generate signalling comprising a repeating beacon signal for receipt by the vibration monitoring device in said signalling. In one or more embodiments, the at least one equipment identification module includes motion-activating circuitry configured to provide for activation, from a low-power state, 30 of said equipment identification module, based on detection of motion above a threshold level and wherein the at least one equipment identification module is configured to generate one or more instances of the repeating beacon signal in response to said activation. 35 In one or more embodiments, the at least one equipment identification module is configured to enter said low-power state after transmission of one or more instances of said repeating beacon signal and wherein the equipment identification module is configured to transmit a further instance of the repeating beacon signal only if said motion-activating circuitry provides for activation, from the low-power state, of said equipment identification module, based on detection of motion above the threshold level. In one or more embodiments, said at least one equipment identification module is 5 battery powered. There now follows, by way of example only, a detailed description of embodiments of the invention with reference to the following figures, in which: 10 Figure 1 shows an example overview of a vibration monitoring system; Figure 2 shows an example vibration monitonng device of the vibration monitoring system; 15 Figure 3 shows a more detailed view of the example vibration monitoring device; Figure 4 shows an example equipment identification module of the vibration monitoring system; 20 Figure 5 shows an example vibration logging device of the vibration monitoring system; Figure 6 shows a flowchart illustrating an example of the operation of the 25 vibration monitoring device; and Figure 7 shows a flowchart illustrating an example of the operation of the equipment identification module, 30 Vibration exposure systems exist to measure and thereby protect operators of vibration generating equipment from excessive exposure to hand arm vibration (HAV) and whole body vibration (WBV). Vibration generating equipment may include powered hand tools, ride-on machinery or vehicles, 35 Such systems typically consist of a vibration measuring device that is carried by the operator of the equipment and an equipment identification tag that is attached to the equipment being monitored. In general, the tag is read by the vibration measuring device to identify the equipment, that the operator is currently using. The identifying information may allow for addition characteristics of the equipment to be determined. Accordingly, known vibration exposure systems have typically used a short range radio frequency transmitter / receiverto identify that the vibration measuring device is within the immediate vicinity of the equipment identification tag (and hence the equipment 5 being monitored). Alternatively, known vibration exposure systems have typically used a passive radio frequency identification (RFID) tag to indicate that the vibration measuring device is mounted on or very near to the equipment identification tag (and hence the equipment being monitored). 10 Other methods include the use of a direct electrical connection between the vibration measuring device and the equipment being monitored to identify that the vibration measuring device is attached to the equipment being monitored. However, in a general work environment, electrical connections can easily become damaged or contaminated and therefore these types of systems are seldom used. Both the short range radio connection system and the RFID connection system have been found to have merits and short comings. An RFID based system may benefit from being a completely passive (does not need a 20 power source) equipment identification tag which can be attached to the equipment. This means that the equipment identification tag may be used indefinitely without need for changing / charging a power source, such as a battery. The downside of this type of system is that during the read period, the measurement device must fully energize the passive tag and therefore a large amount of current must be drawn from the vibration 25 measuring device, which is typically powered by a battery. This may require the use of a higher capacity battery. Alternatively, this may not be a major issue in circumstances where the battery of the vibration measuring device can be easily charged or replaced but it certain scenarios, such as explosive work environments (ATEX), replaceable batteries or charging mechanisms may not be desirable for safety reasons. 30 A short range radio based system may benefit from the ability to register that a vibration measuring device is in the vicinity of an equipment identification tag without actually having to physically mount or connect them. However, this benefit can also be a short coming when the vibration measuring device is in the vicinity of multiple 35 equipment identification tags because the vibration measuring device may erroneously believe it is connected to the incorrect tag (and hence instigate an erroneous vibration exposure measurement). A further short coming of this type of system is that the equipment identification tag must have a power source to allow it to emit a radio beacon signal and the vibration measuring device must continually listen for the radio signs! from the tag, which has an adverse effect on battery iife of the vibration measuring device and the tag. Embodiments of the disclosure relate to a system 101 intended to measure the Hand 5 Arm Vibration (HAV) and Whole Body Vibration (WBV) exposure levels experienced by operators of vibration generating equipment. Example figure 1 shows a vibration monitoring system 101, The system 101 comprises a vibration monitoring device 102 for measuring the vibrations. The vibration 10 monitoring device 102 is typically associated with or assigned to an operator 103 whose vibration exposure level is being monitored by measurement of the vibration they experience through use of the equipment. The vibration monitoring device 102 may be carried by or mounted to the body of the operator 103, such as at the wrist or mounted on a belt. In one or more examples, the vibration monitoring device 102 may 15 be coupled to the vibration generating equipment 105 being used by the operator 103, such as to a structure of an equipment identification module 104 that is itself secured to the equipment 105. The equipment identification module 104 (sometimes known as a "tag") is for 20 identifying the equipment 105 being used. Thus, the equipment identification module 104 may be configured to transmit a signal wirelessly to the vibration monitoring device 102 containing information identifying the module 104. The equipment identification module 104 is configured to be coupled to the vibration generating equipment 105, such as affixed to the vibration generating equipment 105. In other examples, the 25 equipment identification module 104 may be an integral part of the vibration generating equipment 105. Figure 1 shows a power drill as an example of vibration generating equipment 105, although it will be appreciated that the vibration generating equipment 105 may be any type of tool, plant, machinery or vehicle that may generate vibrations in use. 30 The equipment identification module 104 may include a first part of a complementary releasable coupling structure, such as a mount, and the vibration monitoring device 102 may comprise the second part, which fits into the mount. The coupling structure may therefore be configured to provide for releasable coupling together of the 35 equipment identification module 104 and the vibration monitoring device 102. The system 101 also includes a vibration logging device 106 for receiving data indicative of the measured vibrations from one or more of the vibration monitoring devices 102, Thus, for a user of the system 101, there are typically a plurality of vibration monitoring devices 102 and a plurality of operators 103 whose vibration exposure levels are to be measured. The vibration logging device 106 may comprise a receiver or transceiver module 107 and a database 108 in which the measured vibration exposure and equipment information is stored. In this example, the data 5 gathered by the vibration monitoring devices 102 is configured to be wirelessly received from the vibration monitoring devices 102 via the transceiver module 107 and collated in the database IOS. The database 108 may comprise the main user interface to the system 101 and may be configured to allow access to vibration exposure data for operators 103 and allow system administrators to configure parameters in the 10 vibration monitoring devices 102. The database 108 may be customisable. The database 108 may be interrogated to generate reports to analyse vibration exposure data and equipment usage statistics. The database 108 or, in particular, a processor (not shown) associated with storage 15 (not shown) for storing the data of the database, may be configured to process the data / information in the database. For example, the processor of the database 108 may be configured to record the information identifying the module 104. The processor of the database 108 may be configured to generate a report on the equipment(s) 105 being used by a particular operator 103. The processor of the database 108 may be 20 configured to identify when an operator 103 uses a piece of equipment 105 that they are not trained for or allowed to use (based on predetermined training information). The processor of the database 108 may be configured to identify which equipment 105 from a plurality of equipment 105 is being used and for how long. The processor of the database 108 may be configured to generate maintenance schedules for each item of 25 equipment 105 based on the usage recorded in the database. The processor of the database 108 may be configured to identify equipment or groups of equipment 105 which are under / over-subscribed. The processor of the database 108 may be configured to provide asset tracking from the information in the database. For example, it can be identified when a tool / equipment was last seen and which operator 105 was 30 using it. Figure 2 shows an example embodiment of a v^braton monitoring device 102 and Figure 3 shows a more detailed embodiment of the vibration monitoring device 102. 35 Referring to example Figure 2, the vibration monitoring device 102 comprises a vibration measurement sensor 201 configured to measure vibrations for use in determining the vibration exposure of the operator 103. The vibration monitoring sensor 102 may comprise an accelerometer, although other sensor types may be used, such as a piezoelectric sensor. The vibration monitoring device 102 may include a radio receiver and, in this example, comprises radio transceiver 202, which is configured to receive and optionally decode information within signalling received from the one or more equipment identification 5 modules 104. The radio transceiver 202 of this example is configured to transmit vibration exposure messages to the vibration logging device 106. The vibration monitoring device 102 may include an optional motion sensor 203, which may be configured to detect motion for waking-up the vibration monitoring device 102. 4 f. The vibration monitoring device 102 may include a power source 204, such as a battery. The vibration monitoring device 102 may include a processor 205, such as a general 15 purpose processor, a field-programmable gate array, FPGA, or an application-specific integrated circuit, ASIC. The processor 205 may be configured to processes the output from the vibration measurement sensor 201 to calculate the vibration exposure. The processor 205 may be configured to process the received information, that identifies the equipment 105, from the equipment identification module 104. The processor 205 20 may be configured to operate on the signalling from the radio transceiver 202 to decode the information within signalling received from the one or more equipment identification modules 104. The processor 205 may perform one or more other tasks for the vibration monitoring device 102, such as motion sensing, battery level sensing, or wake up sensing, as will be described below. 25 In this example, the processor 205 may comprise a separate component configured to receive information from and process that information from one or more of the sensor 201, the motion sensor 203 and the radio receiver / transceiver 202. In an alternate embodiment, the processing functionality provided by the processor 205 may be 30 distributed rather than centralised and therefore, for example, the decoding of the signalling may be provided by processing functionality integral with the radio transceiver 202 and / or the vibration measurement sensor 201 may including processing functionality integral therewith for interpreting the output of sensor to calculate a value representative of vibration exposure. 35 The vibration monitoring device 102 may be housed within an enclosure 206, which may be of rugged plastics or metal. The vibration monitoring device 102 comprises a wake-up receiver 206 configured to receive signalling including from at least one equipment identification module 104 for identifying the equipment 105 being used by the operator 103. The wake-up receiver 206 is configured to detect a predetermined feature in said signalling indicative of the 5 signalling originating from said equipment identification module 104. The predetermined feature may comprise a feature identifiable prior to decoding the information contained within the signalling. Thus, the form of the signalling may be distinctive in addition to the information within it. For example, said predetermined feature may comprise one or more of (a) a predetermined pulse width where the 10 signalling is transmitted in a one or more pulses (e.g. time-spaced transmissions); (b) a predetermined pattern of a plurality of pulses in said signalling; (c) a predetermined frequency; or (d) a predetermined signal amplitude. In one or more examples, the predetermined amplitude requirement may be achieved 15 by including attenuation in the receive path from the antenna to the wake-up receiver 206 so that only signalling with sufficient power is received. The attenuation could be selected so that only signals from a nearby equipment identification module 104 would reach the wake-up receiver. Thus, the expected signal power of the equipment identification module 104 at a particular distance may be known and the attenuation 20 can be selected such that the signalling received by the wake-up receiver would only be above its minimum sensitivity if the equipment identification module 104 is closer than a predetermined distance away. This provides an advantageous power reducing strategy for mitigating against an environment with numerous equipment identification modules 104. 25 In response to detection of said predetermined feature, the wake-up receiver 206 is configured to provide a wake-up control signal to provide for activation, from a low-power state, of a further receiver for decoding said signalling and, in particular, subsequently received signalling. The decoding of the signalling may provide for 30 extraction of identifying information that identifies the equipment identification module 104 and therefore the equipment 105. The further receiver, in this example, comprises the radio transceiver 202. The vibration monitoring device 102 may be configured to collect data from the vibration measurement sensor 201 to measure vibration only once awoken by the wake-up control signal. The further receiver 202 may be 35 configured to use a communication protocol including Bluetooth®, Bluetooth LE®, WiFi, Zigbee, Z-wave or other low power and secure RF transmission. In one or more examples, the further receiver 202 may be configured not to use a communication protocol that uses an electromagnetic interrogation pulse to irradiate the equipment identification module 104 with energy to power its circuitry and enable it to respond, such as RFID or NFC. Such a protocol has been found, in one or more examples, to not provide power efficiency overall. The wake-up receiver 206 has lower power consumption than said radio transceiver 5 202 (i.e. the further receiver) when in use and therefore power savings are gained by using the low power wake-up receiver 206 to turn the further receiver 202 from the low-power state to an on-state by way of said wake-up control signal 207. The low-power state may comprise an off-state. 10 Accordingly, the wake-up receiver 206 may be powered by the battery 204 or other power source while the circuitry of the radio transceiver 202 is in a low-power state. The low-power state may be such that the radio transceiver 202 (i.e. the further receiver) is not supplied with power or supplied with power but at a lower level than when it is configured to operate in the receipt of the signalling. Accordingly, the wake-15 up control signal may wake the radio transceiver 202 from its low-power state to enable it to transition to an on-state in which it can successfully receive the information in the signalling from the one or more equipment identification modules 104. Thus, in one or more examples, the wake-up control signal may be provided to the radio transceiver 202 to cause it to awaken. In other examples, the wake-up control signal may be 20 provided to a power switch that, when triggered by said wake-up control signal, provides for power, such as from the battery 204, to be provided to the radio transceiver 202. Accordingly, the radio transceiver 202 may not be provided with power until the wake-up control signal is provided. In another example, the wake-up control signal may be provided to the processor 205, which may, in turn, wake-up the 25 radio transceiver 202. In one or more examples, the radio transceiver 202 may not be the only component configured to be awoken from a low-power state (e.g. including a no power state) by the wake-up control signal from the wake-up receiver 206. 30 In one or more examples, said vibration monitoring device 102 is configured such that said wake-up control signal from the wake-up receiver 206 is configured to provide for activation, from a low-power state, of circuitry, such as processor 205, configured to process an output of said sensor 201 for measuring said vibration. Similarly, the wake-35 up control signal may activate a switch to cause power to be supplied to the processor 205 or otherwise awaken the processor 205. Similarly, the wake-up control signal may "activate" the sensor 201 in terms of providing a voltage thereto so that the sensor 201 provides an output based on the occurrence of vibrations. In one or more examples, the wake-up control signal may comprise a plurality of wakeup control sub-signals provided to each of the components 201, 202, 205 that require waking up, 5 In terms of placing the further receiver 202 in the low-power state, the vibration monitoring device 102 may be configured to determine at least one of: (a) when the sensor 201 is not monitoring vibrations, such as for at least a first predetermined period of time; (b) when the further receiver 202 is not in communication with one of the 10 equipment identification modules 104, such as for at least a second predetermined period of time; (c) when the vibration monitoring device 102 is not moving or moving less than a threshold level of movement, such as determined by the motion sensor 203, such as for at least a third predetermined period of time; 15 and if one or more of said conditions are met, the vibration monitoring device 102 may place the components thereof, at least including the further receiver 202, in the low-power state. It has been found that the use of a wake-up receiver 206 in combination with a further 20 receiver 202 has been found to be particularly power efficient while allowing for robust communication between the vibration monitoring device 102 and the equipment identification module 104. In particular, in examples where the further receiver 202 is configured to use a communication protocol that requires both the further receiver 202 and the equipment identification module 104 to have their own power source, the use 25 of the wake-up receiver 206 has been found to reduce power consumption significantly. The present embodiment has been found to reduce power consumption to a similar level or less compared to a passive system (e.g. RFID), while gaining advantages in terms of information exchange. Thus, while a passive system may be considered to be low power, the downside is that during a read period when the reader must fully 30 energize the passive RFID tag, a large amount of current is required to be drawn from the battery. The use of a wake-up receiver 206 has been found to provide a surprisingly power efficient system. The vibration monitoring device 102 may include motion-activating circuitry configured 35 to activate the wake-up receiver 206 on detection of motion. The motion-activating circuitry may comprise the motion sensor 203 in combination with the processor 205 in the example of Figure 2. The motion-activating circuitry is configured to provide for activation, from a low-power state, of said wake-up receiver 206, based on detection of motion above a threshold level Thus, the vibration monitoring device 102 may be configured to determine when the vibration monitoring device 102 has not been used and / or has been still for a predetermined period of time, and the components thereof, at least including the wake-up receiver 206, may be placed in the low-power state. The motion-activating circuitry may be configured to wake the wake-up receiver 206 5 from the low power state. In the low-power state, the wake-up receiver 206 may not be able to detect the predetermined feature in said signalling indicative of the signalling originating from said equipment identification module 104. However, once the motion-activating circuitry 203, 205 detects motion above the threshold it may be determined that the vibration monitoring device 102 is in use and the wake-up receiver 206 may 10 be activated so that it can begin to detect the predetermined feature in said signalling. The combination of the motion-activating circuitry 203, 205 and the wake-up receiver 206 has been found to be particularly power efficient while allowing for use of a radio transceiver 202 that may use wireless communication protocols, such as Bluetooth®, 15 A radio protocol such as Bluetooth® has been found to provide iink security, robustness and power efficiency during the exchange of the identifying information. However, it has also been found that using Bluetooth to asynchronously identify that the vibration monitoring device 102 is in very close proximity to (or mounted on) an equipment identification module 104 is power inefficient. It has been found that it would require 20 that the Bluetooth receiver in the vibration monitoring device 102 would have to be permanently powered otherwise the ver / short (e.g. approx. 1ms) radio signal from the equipment identification module 104 could be missed. Thus, whilst a radio protocol like Bluetooth® has been found to provide benefits in the exchange of the identifying information, there has been found to be disadvantages when Bluetooth is used to 25 "search" for equipment identification module 104 to connect to. Hence, the use, by system 101 of the present embodiment, of the very low power wake up receiver 206 enables the signalling to be asynchronously detected and then the robustness and security of the Bluetooth protocol can confirm that the vibration monitoring device 102 is indeed in the immediate vicinity of the equipment identification module 104. This 30 advantageously overcomes the disadvantages of the Bluetooth protocol for this application (or similar RF protocol) while preserving the advantages. The power efficiency of the system 101 can be improved further by using the even lower power motion-activating circuitry 203, 205 to disable the wake up receiver 206 when the vibration monitoring device 102 is at rest (the presumption being that at rest it is not 35 in use). The use of motion-activating circuitry may be taken further with the module 104, as will be described below, to reduce the proliferation of signalling that could occur where there are a large number of tools / equipment 105 (and hence equipment identification modules 104) at rest in a tool store, or the like. In the exampie of Figure 2, the sensor 201 is shown separately from the motion sensor 203. Thus, in one or more examples, they may be separate sensors. In one or more examples, the sensors 201, 203 may be of different sensor types. For example, the vibration monitoring sensor 201 may comprise an accelerometer and the motion sensor 5 203 may comprise a piezoelectric based motion sensor. In other examples, said motion-activating circuitry is configured to detect said motion using said vibration measurement sensor 201. Example Figure 3 shows a more detailed view of the vibration monitoring device 102 10 and, in particular, the wake-up receiver 206. The wake-up receiver 206 includes an antenna port 301 from which to receive said signalling. The antenna port 206 is configured to be coupled to an antenna for wireless reception of the signalling and the wireless transmission of messages, such as to the 15 vibration logging device 106. The signalling from the antenna port 301 may pass through an RF filter 3Q2, which may comprise a band-pass filter, to restrict the bandwidth of the received signalling to a radio band of interest. In one or more examples, the band of interest for the wake-20 up receiver 206 may be different to the band of interest for the further receiver 202, but in this example all signalling from the antenna port 301 is filtered by the RF filter 302. In one or more examples, the vibration monitoring device 102 includes a first 25 switch 303 configured to route the signalling to said wake-up receiver 206, via path 304, when the further receiver 202 is in the low-power state. Accordingly, in the low-power state the further receiver 202 may not receive said signalling because it is routed to the wake-up receiver 206. In response to the wake-up control signal, the first switch 303 is configured to route said signalling to the further receiver 202, via path 305. 30 Thus, in the on-state of the further receiver 202, the wake-up receiver 206 may not receive said signalling because it is routed to the further receiver 202. The routing of the Signalling to either the wake-up receiver 206 or the further receiver 202 may be advantageous in terms of power efficiency. 35 The wake-up receiver 206 includes circuitry for identifying the predetermined feature in the signalling that is indicative of the signalling originating from said equipment identification module 104. Thus, the wake-up receiver 206 is configured to be responsive to the predetermined feature, which while present in signalling that originates from said equipment identification module 104, is not conclusively indicative of the origin of the signalling. For example, it is possible that other signalling not from the equipment identification module 104 may have the predetermined feature. Accordingly, decoding performed by the further receiver 202 may be required to determine that the signalling having the predetermined feature is, in fact, signalling 5 that originates from said equipment identification module 104 and from which an identification of the equipment 105 can be made. The selection of the predetermined feature may therefore need to reach a balance between identifying a signal feature that is sufficiently unique or complex so that the 10 wake-up receiver 206 does not erroneously generate the wake-up control signal, but is also sufficiently simple so as not to require power intensive circuitry for its detection. The use of an envelope detector circuit in combination with pulse width measurement circuitry has been found to be particularly advantages. 15 In one or more examples, the wake-up receiver 206 includes an envelope detector circuit 306 that is configured to extract the envelope of the incoming signalling, which may include the signalling from the equipment identification module 104. The envelope detector circuit 306 may comprise a half-wave or full-wave rectifying circuit, although envelope detector circuits will be known to those skilled in 20 the art of RF electronics. In one or more examples, the wake-up receiver 206 includes a comparator 307 that receives the envelope of the signalling and is configured to compare the voltage of the envelope of the signalling to a threshold voltage amplitude in order to filter out 25 envelopes below the threshold voltage amplitude. If the envelope of the signalling is greater than the threshold voltage amplitude it is passed to a ramp generator 308. In one or more examples, the wake-up receiver 206 includes a ramp generator 308 that is configured to convert the envelope of the signalling to a voltage signal so that 30 the pulse width (i.e. time) of the incoming signalling can be extracted. The ramp generator 308 is an example of circuitry that is configured to translate the width of the pulse (i.e. time) into a voltage amplitude for further processing. In one or more examples, the envelope of the incoming signalling is presented to the ramp generator 308, which may be embodied as an RC low pass filter, and the ramp generator 308 is 35 configured to output a linear ramp voltage wherein the amplitude of the linear ramp voltage is correlated to the width of the incoming "wake up" signalling. In one or more examples, the wake-up receiver 206 includes a window comparator 309 that uses the voltage signal from the ramp generator 308 to measure the pulse width of the signaling. Thus, the amplitude of the signal output from the ramp generator 308 is indicative of the pulse width and the window comparator 309 is configured to determine if this amplitude is within a predetermined voltage range. Thus, this is, in effect, determining whether the puise width is within a predetermined 5 time range. Thus, in this example, detection of a pulse width based on the envelope of the signalling that is equal to a predetermined puise width (within a tolerance) will trigger the generation of the wake-up control signal. The detection of a pulse width based on the envelope of the incoming signalling has been found to be particularly power efficient and can allow for the use of components in the wake-up receiver that 10 are suitable for lower frequencies rather than the frequencies at which the information in the signalling is encoded. In one or more examples, the wake-up receiver 206 includes a sampler 310 that samples the output of the window comparator 309 at the instanta pulse in the envelope 15 of the signalling ends, which, is indicative of the width of the pulse in time. Thus, to summarise, the envelope of the incoming "wake up" signal is fed to a RC low pass filter (an example of the ramp generator 308). The time domain response of the RC low pass filter to a step voltage at its input is a linear "RC ramp" voltage at its 20 output. The amplitude of the linear RC ramp voltage at any given time after the step voltage input has occurred will be determined by the amplitude of the voltage step and the RC time constant of the RC low pass filter. The expected pulse width of the incoming "wake up" signal and the RC time constant is known, so it can be determined what voltage the RC ramp voltage will have risen to at the end of the incoming pulse. By 25 knowing this voltage the output of the ramp generator 308 is applied to the input of a window comparator 309 (with comparator thresholds of the window comparator set accordingly). The output of the window comparator 309 is configured only to be in a high state when the voltage ramp is at a value indicative of the predetermined pulse width. If the output from the ramp generator 308 is any lower or higher (+ / - a 30 tolerance) the window comparator 309 will be in a low state. Therefore, the sampling of the output of the window comparator on the falling edge of the detected envelope, by the sampler 310, will only generate a "wake up" event T the pulse width is equal to the predetermined pulse width (+ / - a tolerance), 35 In one or more examples, the sampler 310 provides a signal to the processor 205 to indicate that the predetermined feature (the pulse width equal to the predetermined pulse width) has been identified. The signal may comprise an interrupt for the processor. The processor 205 may be configured to react to receipt of the signal, which may comprise being configured to be triggered on an edge, such as a rising edge, of the output from the sampler 310. In this example, the output of the sampler 310 may be considered to comprise the wake-up control signal. It will also be appreciated that the wake-up control signal may be provided directly to the radio transceiver 202 (i.e. further receiver) or to trigger a power switch that supplies power to the radio 5 transceiver 202 (i.e. further receiver) and optionally one or more other components, such as those shown in Figure 2, or to the processor 205. The vibration monitoring device 102 of example Figure 3 includes at least two different 10 signal paths between the further receiver 202 and the antenna terminal 301 comprising a first signal path 311 and a second signal path 312, wherein said vibration monitoring device is configured to route signalling from the antenna terminal 310 to the further receiver (embodied as transceiver 202) via said first signal path 311; and route signalling from a transmitter (embodied as transceiver 202) to the antenna terminal 15 310 via the second signal path 312, The selection of which signal path is used may be provided by a pair of switches comprising first path switch 313 and second path switch 314 at either ends of the signal paths. The first path switch 313 and second path switch 314 are configured to be actuated in tandem to provide the connection via the first signal path 311 or the second signal path 312. 20 The first and second signal paths are provided to manage the ability for the radio transceiver to receive the signalling from only the closest of equipment identification modules 104. Thus, one or both of (a) said first signal path 311 includes a greater level of attenuation than said second signal path 312 and (b) said first signal path 311 25 includes a lower level of signal amplification than said second signal path 312, Thus, the vibration monitoring device is configured to route incoming signalling for the transceiver 202 via the first signal path 311 and outgoing messages from the transceiver 202 via the second signal path 312. Thus, only higher signal power signalling will make it to the radio transceiver 202 via the first signal path 311 thereby 30 ensuring that signalling from only the closest equipment identification modules 104 are received. When the radio transceiver 202 is configured to send a message, it may use the low loss / high signal amplification, second signal path 312 thereby being able to send messages with reduced signal power. Accordingly, the switchable signal paths are advantageous in managing the problem of signal confusion for incoming signalling 35 (confusion between signalling from two or more different modules 104) and advantageous in terms of managing power consumption when transmitting outgoing messages. In this example the vibration monitoring device 102 is configured to perform additional analysis to reduce the chance that the vibration monitoring device 102 receives the identifying information from the wrong (i.e. more distant) equipment identification module 104. 5 In the present and one or more other examples, the processor 205 in response to the wake-up control signal, or the output from the wake-up receiver 204, is configured to cause the first switch 303 to direct the signalling along path 305 to the further receiver 202. Further, the processor 205, or more generally the vibration monitoring device 10 102, is configured to select the first (high ioss / low signal amplification) signal path 311 by actuation of the first path switch 313 and the second path switch 314. The further receiver 202 can now receive the signalling. Thus, in response to having been activated by said wake-up control signal, the further receiver 202 or further 15 receiver 202 in combination with the processor 205 may be configured to: measure the received signal strength of said signalling and, in particular, of an instance of a repeating beacon signal from the equipment identification module; and (a) if the signalling has a received signal strength lower than a received signa! strength threshold, the signalling is ignored by said further receiver 202; and 20 (b) if the signalling has a received signal strength greater than the received signal strength threshold, the Signalling is decoded by said vibration monitoring device 102 (such as by processor 205 and / or further receiver 202) to enable the extraction of identifying information from said signalling that identifies said at least one equipment identification module 104 and therefore the equipment 105. Thus, prior to decoding, 25 the identifying information may not be able to be determined from the signalling. The signal strength may be determined based on determining a received signa! strength indicator (RSSI) measurement of the signalling comprising the beacon signal from the module 104. Alternatively, other signal strength measurements may be made, 30 such as power in a band. In one or more examples, the equipment identification modules 104 may be configured to transmit with a fixed signal power thereby allowing for the further receiver 202 to judge distance based on received signal power. In one or more other examples (not shown), said wake-up receiver 206 is configured 35 to measure the received signa! strength of said signalling,, and the provision of the wake-up control signal is further based on the signalling having a received signal strength greater than a received signal strength threshold. Thus, the vibration monitoring device 102 may be configured such that upon receipt of the wake-up controi signal from the wake-up receiver and the further receiver 202 determining that the signal strength exceeds the signal strength threshold, the processor 205 may be configured to determine the identifying information that 5 identifies the vibration generating equipment 105 and may begin logging the vibrations detected by the sensor 203. The device 102 may be configured to associated the measure of the vibrations with the equipment 105 for sending to the vibration logging device 106. Thus, the vibration monitoring device may be configured to decode said signalling, perhaps after performing a pairing process with the module 104 to extract io identifying information from said signalling (containing the instances of the beacon signal) that identifies said at least one equipment identification module 104. The device 102 and therefore the processor 205 can then measure, using said sensor 203, the HAV or WBV of an operator 103, wherein said vibration is determined to be generated by the vibration generating equipment identified by the identifying information from 15 the at least one equipment identification module 104. The measuring of the HAV / WBV may continue at least until said vibration monitoring device determines that said same identifying information is no longer present in the signalling and / or that no further vibrations are detected. The vibration monitoring 20 device 102 or processor 205 thereof may then be configured to generate a vibration exposure message including said measured HAV / WBV and said identifying information for transmission to a vibration logging device. In order to transmit said message, the first path switch 313 and the second path switch 314 may be actuated to select the second Signal path 312 so that the message can be sent to the antenna 301 with lower 25 attenuation that than provided by the first signal path 311. In other examples, a plurality of vibration exposure messages may be queued for sending at a later time. Example figure 4 shows an example equipment identification module 104. The module 104 may be configured to be attached to the equipment 105 being monitored. The 30 module 104 is used to indicate to the vibration monitoring device 102 (and thereby the vibration logging device 106) the type of equipment or uniquely identify the equipment 105. In one or more examples, the vibration monitoring device 102 is configured to be 35 mounted to the equipment 105 by the module 104. Thus, the module 104 may comprise a receptacle or mount to releasably receive the vibration monitoring device 102 to couple the vibrations generated by the equipment 105 being monitored into the vibration monitoring device 102. The equipment identification module 104 comprises a radio transmitter or a radio transceiver device 401 which is configured to repeatediy generate a beacon signal that has the predetermined feature and which contains the identifying information relating to the equipment 105 that the module 104 is attached to. Instances of the repeating 5 beacon signal may thus be transmitted with times of non-transmission therebetween. The equipment identification module 104 may comprise an antenna terminal 402 which is used to couple to an antenna to radiate the beacon signal signalling to the vibration monitoring device 102, 4 C' ! L? The equipment identification module 104 may comprise motion-activating circuitry 403. The motion-activating circuitry 403 may be configured to provide for activation, from a low-power state, of said equipment identification module 104, based on detection of motion above a threshold level and wherein the at least one equipment 15 identification module is configured to generate its repeating beacon signal in response to said activation. Thus, in one or more examples, each instance (or a predetermined plurality of instances) of the repeating beacon signal may be transmitted only if motion is continued to be detected by the motion-activating circuitry 403. Accordingly, the transceiver device 401 may be configured to, for each instance or plurality of instances 20 of the repeating beacon signal, check whether or not the motion-activating circuitry 403 indicates that motion is present. If so, the next instance or instances of the beacon signal are transmitted and, if not, the beacon signal is not transmitted, at least until motion is once again detected. 25 The equipment identification module 104 may comprise a power source, such as a battery 404. The equipment identification module 104 may comprise a rugged enclosure 405 to house the transmitter 401 and the motion sensor 403 and the battery 404. 30 Example figure 5 shows the transceiver module 107 of the vibration logging device 106. The transceiver module 107 is usually located within the work environment where vibration exposure is being monitored. The transceiver module 107 effectively acts as a relay between the one or more vibration monitoring devices 102 and the database 35 108 and allows the vibration monitoring system 101 and, in particular, a computing device associated with the database 108 to report exposure warnings in real time (e,g. via push notification or email) to operators 103, their line managers and / or Health &Safety Officers, as required. Referring to example figure 5, the transceiver module 107 comprises a system processor 501 which is used to process and format messages. The transceiver module 107 includes a radio transceiver 502. The radio transceiver 502 is coupled to an antenna terminal 503 for coupling to an antenna. The transceiver module 107 may 5 include a communications processor 504 which may be used as a gateway giving access to a wider network, such as a wired ethernet and / or wireless connectivity to the database. The transceiver module 107 also includes a suitable power source (typically an external DC input or battery 505. The system processor 501 and communications processor 504 may, in some examples, comprise the same processor. 4 C' ! L? The operation of the vibration monitoring system 101 will now be described with reference to example figure 6, which depicts an example process of operation for the vibration monitoring device 102. Figure 6 shows an example of managing the connection to an equipment identification module 104 and also an example of how the 15 vibration monitoring device 102 handles the vibration exposure measurement. Step 601 shows the vibration monitoring device 102 in the low-power state. The low-power state may be a default state of the vibration monitoring device 102. In the low-power state a very low current is drawn from the batten / 204 to power the motion-20 activating circuitry. The vibration monitoring device 102 may be configured to revert to the low-power state unless conditions are met as will be described. In the low-power state, the motion sensor 203 is active in that it is provided with sufficient power to detect motion while the other components of the vibration monitoring device 102 are inactive or switched off. 25 Step 602 represents the motion sensor 203 repeatedly or periodically sensing for motion above a threshold. As mentioned above, the motion sensor 203 may operate independently to perform its sensing function or may operate in combination with the processor 205. If motion is detected, the motion sensor 203 is configured to generate 30 an interrupt for the processor 205 and the process proceeds to step 603. If no motion above the threshold is detected, the processes returns to the low-power state represented at step 601. The processor 205 is the low-power state awaiting the interrupt from the motion sensor 203. All the other components of the vibration monitoring device 102, including the wake-up receiver 206 and further receiver 202, 35 are off. Step 603 shows the wake-up receiver 206 being activated from its low-power state or turned on. The vibration monitoring device 102 may be configured such that the wake up receiver 206 remains activated (e.g. on) for as iong as motion is detected plus a finite predetermined time beyond motion being detected by the motion sensor 203. Step 604 represents the wake-up receiver 206 being configured to look for the 5 predetermined feature in the signalling received via the antenna 301. If the predetermined feature is identified, that is the wake-up receiver 206 detects a pulse width equal to (± a tolerance) a pulse width present in the beacon signal from an equipment identification module 104, it will notify the processor 205 by an interrupt. The processor 205 will then enable the further receiver 202 at step 605 to allow the 10 next incoming radio beacon signal to be received by the further receiver 202 rather than the wake-up receiver. Thus, the interrupt from the wake-up receiver 206 may be considered the wake-up control signal, wherein the wake-up receiver 206 uses the processor 205 to activate the further receiver 202. 15 Step 606 shows receipt of a subsequent instance of the beacon signal from the equipment identification module 104 by the further receiver 204. If the RSSI of the subsequent instance of a beacon signal is below the received signal strength threshold, then the further receiver 204 will reject it and the process returns to step 602. However, if the subsequent instance of the beacon signal is above the received signal 20 strength threshold, then the further receiver 204 is configured to decode and check the information present in the beacon signal that forms part of the signalling received by the vibration monitoring device 102. Step 607 shows a step performed by the further receiver 204 or the processor 205 or 25 a combination of the two. If the decoded beacon signal is identified as originating from an equipment identification module 104, the further receiver 204 is configured to notify the processor 205. The vibration monitoring device 102 is now effectively "paired" with equipment identification module 104 and the vibration exposure measurement can begin at step 608. 30 The vibration exposure measurement of step 608, is configured to continue whilst the equipment identification module's 104 repeating beacon signals are still being detected, as shown at step 609, wherein the process returns to step 608, 35 When the beacon signals are no longer detected (plus a finite predetermined time beyond cessation of detection) the vibration exposure measurement will stop and the processor 205 is configured to determine that the vibration monitoring device 102 has been removed from the mount of the equipment identification module 104 or otherwise moved away. At this point, the vibration monitoring device 102 and the equipment identification moduie 104 are effectively no longer "paired" and the method proceeds to step 610. At step 610, a vibration exposure message is constructed by the processor 205 and 5 passed to the transmitter / transceiver 204 for transmission to the database 108 via the transceiver 107 or, alternatively, it may be stored for later transmission. The operation of the equipment identification module 104 will now be described with reference to example figure 7, which depicts how the equipment identification module 10 104 may manage the transmission of its beacon signals. The equipment identification module 104 nominally operates in a low power state in which there is very low current consumption, shown by step 701. In this state, the motion-activating circuitry 403 is on and configured to generate an activation signal 15 when any motion is detected, as represented by step 702 which represents the condition of detecting motion. The radio transmitter 401 is configured to be in a low power state awaiting the activation signal from the motion-activating circuitry 403. AH other circuitry within the equipment identification module 104 is in a low-power state, such as switched off. 20 When motion is detected the method proceeds to step 703 and when no motion is detected, the low power state of the equipment identification module 104 is maintained. Step 703 shows the radio transmitter 401 activated by the activation signal and therefore switched on. 25 Step 704 shows one or more instances of the beacon signal being transmitted. Step 705 represents the delay period between one or more instances of the repeating beacon signal. The radio transmitter 401 enters the low-power state for the predetermined delay period. 30 Once the delay period had elapsed and assuming that motion is still being detected then the process of generating the next instance of the repeating beacon signal is repeated from step 702, However, if no motion is detected then the equipment identification module 104 returns to the low power state at 701. 35 While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and have been described in detail. It should be understood, however, that other embodiments, beyond the particular embodiments described, are possible as well. AH modifications, equivalents, and alternative embodiments falling within the scope of the appended claims are covered as well. The instructions and / or flowchart steps in the above figures can be executed in any 5 order, unless a specific order is explicitly stated. Also, those skilled in the art will recognize that while one example set of instructions / method has been discussed, the material in this specification can be combined in a variety of ways to yield other examples as well, and are to be understood within a context provided by this detailed description. 4 C' ! L? In some example embodiments the set of instructions / method steps described above are implemented as functional and software instructions embodied as a set of executable instructions which are effected on a computer or machine which is programmed with and controlled by said executable instructions. Such instructions are 15 loaded for execution on a processor (such as one or more CPUs, ASICs for FPGAs). The term processor includes microprocessors, microcontrollers, processor modules or subsystems (including one or more microprocessors or microcontrollers), or other control or computing devices. A processor can refer to a single component or to plural components. 20 In other examples, the set of instructions / methods illustrated herein and data and instructions associated therewith are stored in respective storage devices, which are implemented as one or more non-transient machine or computer-readable or computer-usable storage media or mediums. Such computer-readable or computer 25 usable storage medium or media is (are) considered to be part of an article (or article of manufacture). An article or article of manufacture can refer to any manufactured single component or multiple components. The non-transient machine or computer usable media or mediums as defined herein excludes signals, but such media or mediums may be capable of receiving and processing information from signals and / or 30 other transient mediums. In one example, one or more instructions or steps discussed herein are automated. The terms automated or automatically (and like variations thereof) mean controlled operation of an apparatus, system, and / or process using computers and / or 35 mechanical / electrical devices without the necessity of human intervention, observation, effort and / or decision. It will be appreciated that any components said to be coupled may be coupled or connected either directly or indirectly. In the case of indirect coupling, additional components may be located between the two components that are said to be coupled. 5 In this specification, example embodiments have been presented in terms of a selected set of details. However, a person of ordinary skill in the art would understand that many other example embodiments may be practiced which include a different selected set of these details. It is intended that the following claims cover all possible example embodiments. 09 06 23

Claims

1. A vibration monitoring device for measurement of one or both of hand arm vibration, HAV, and whole body vibration, WBV, of an operator using vibration 5 generating equipment, the device comprising:a wake-up receiver and a further receiver, wherein the wake-up receiver is configured to receive signalling including from at least one equipment identification module for identifying the equipment being used by the operator, and wherein the wake-up receiver is configured to detect a predetermined feature in said signalling 10 indicative of the signalling originating from said equipment identification module and, in response to detection of said predetermined feature, provide a wake-up control signal to provide for activation, from a low-power state, of the further receiver for decoding said signalling, wherein the further receiver is, in response to having been activated by said wake-up control signal, configured to:15 measure the received signal strength of said signalling; andwherein signalling having a received signal strength lower than a received signal strength threshold is ignored by said further receiver and signalling having a received signal strength greater than a received signal strength threshold is decoded by said vibration monitoring device to extract identifying information 20 from said signalling that identifies said at least one equipment identificationmodule; anda sensor configured to measure vibration.

2. The vibration monitoring device according to claim 1, wherein said 25 predetermined feature comprises one or more of:a) a predetermined pulse width;b) a predetermined pattern of a plurality of pulses in said signalling; andc) a predetermined frequency.30 3. The vibration monitoring device according to claim 1 or claim 2, wherein saidvibration monitoring device is configured such that said wake-up control signal from the wake-up receiver is configured to provide for activation, from a low-power state, of circuitry of the vibration monitoring device that is configured to process an output of said sensor for measuring said vibration.

354. The vibration monitoring device according to any preceding claim, wherein said vibration monitoring device is configured such that said wake-up control signal causes09 06 23activation of the further receiver by causing power to be provided to said further receiver.

5. The vibration monitoring device according to any preceding claim, wherein said vibration monitoring device includes motion-activating circuitry configured to provide for activation, from a low-power state, of said wake-up receiver, based on detection of motion above a threshold level.

6. The vibration monitoring device according to claim 5, wherein said motionactivating circuitry is configured to detect said motion using said sensor.

7. The vibration monitoring device according to any preceding claim, wherein said wake-up receiver is configured to measure the received signal strength of said signalling, and the provision of the wake-up control signal is further based on the signalling having a received signa! strength greater than a received signal strength threshold.

8. The vibration monitoring device according to any preceding claim, wherein said vibration monitoring device includes a first switch configured to route said signalling to said wake-up receiver until said wake-up control signal is provided whereupon said first switch is configured to route said signalling to the further receiver.

9. The vibration monitoring device according to any preceding claim, wherein said vibration monitoring device comprises:an antenna terminal for coupling to an antenna for receiving said signalling and transmitting messages; andat least two different signal paths between the further receiver and the antenna terminal comprising a first signal path and a second signal path, wherein:said vibration monitoring device is configured to route signalling from the antenna terminal to the further receiver via said first signal path; andsaid vibration monitoring device is configured to route signalling from a transmitter of the vibration monitoring device to the antenna terminal via the second signal path; andwherein one or both of (a) said first signal path includes a greater level of attenuation than said second signal path and (b) said first signal path includes a lower level of signal amplification than said second signal path.09 06 2310. The vibration monitoring device according to any preceding claim, wherein the vibration monitoring device is configured to decode said signalling to extract identifying information from said signalling that identifies said at least one equipment identification module and measure, using said sensor, the HAV or WBV of an operator determined 5 to be generated by the vibration generating equipment identified by the identifying information from the at least one equipment identification module.

11. The vibration monitoring device according to claim 10, wherein said measuring of the HAV / WBV continues at least until said vibration monitoring device determines 10 that said identifying information is no longer present in the signalling.

12. The vibration monitoring device according to claim 10, wherein said measuring of the vibration continues at least until said vibration monitoring device determines that said identifying information is no longer present in the signalling and, in response 15 to determining that the identifying information is no longer present in the signalling, generate a vibration exposure message including said measured vibration and said identifying information for transmission to a vibration logging device.

13. The vibration monitoring device according to any preceding claim, wherein the 20 vibration monitoring device is battery powered.

14. A combination of the vibration monitoring device according to any preceding claim and at least one equipment identification module, the equipment identification module configured to be coupled to a respective vibration generating equipment and 25 generate signalling comprising a repeating beacon signal for receipt by the vibration monitoring device in said signalling.

15. The combination of claim 14, wherein the at least one equipment identification module includes motion-activating circuitry configured to provide for activation, from 30 a low-power state, of said equipment identification module, based on detection of motion above a threshold level and wherein the at least one equipment identification module is configured to generate one or more instances of the repeating beacon signal in response to said activation.35 16. The combination of claim 15, wherein the at least one equipment identificationmodule is configured to enter said low-power state after transmission of one or more instances of said repeating beacon signal and wherein the equipment identification module is configured to transmit a further instance of the repeating beacon signal onlyif said motion-activating circuitry provides for activation, from the low-power state, of said equipment identification module, based on detection of motion above the threshold level.5 17. The combination of any one of claims 14 to 16 wherein said at least oneequipment identification module is battery powered.COCM

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