Patent Description:
It is known to provide a sensor device for sensing an operational characteristic, such as vibration and temperature, of a component in an industrial facility, and typically such a sensor device is arranged to communicate captured temperature and vibration signals to a remote facility for analysis. Typically, such devices use conventional cabling, or wireless communication arrangements for example based on <NUM>. 11x, LTE or <NUM>. <NUM> protocols, to communicate the signals, at least in the vicinity of the industrial facility.

Existing sensor devices for sensing operational characteristics are typically required to be relatively sophisticated because the amount of captured data that is required to be communicated is large. Existing sensor devices also tend to be expensive and tend to consume relatively large amounts of power to the extent that the devices have a life span of the order of <NUM> years, and in some instances several months, which is a significant burden in an industrial facility because a large number of sensor devices are typically used
In addition, conventional communication cabling and communication devices based on <NUM>. 11x, LTE or <NUM>. <NUM> protocols are expensive to the extent that provision of sensor devices in an industrial facility becomes cost prohibitive because of the infrastructure required to support a large number of devices.

Furthermore, wireless communication arrangements based on protocols such as <NUM>. 11x have a relatively high carrier frequency (typically <NUM>), and associated limited range (typically less than <NUM>) and low penetration characteristics through obstacles, particularly metallic obstacles. This is highly undesirable in a typical industrial facility that includes many metallic obstacles. Existing sensor devices for sensing an operational characteristic of a component in an industrial facility are therefore expensive, inefficient and problematic to implement.

The patent document <CIT> discloses a sensor configured for transmitting, by radio, features of an obtained spectrum resulting of a Fourier transformation of time-series data without transmitting the time-series data. This allows reducing the amount of data transmitted by the sensor.

In accordance with the present invention, there is provided a sensor device according to claim <NUM>.

In an embodiment, the selected subset of frequency domain data corresponds to a defined number of frequency peaks in the frequency domain data.

In an embodiment, the selected subset of frequency domain data corresponds to a defined number of the highest frequency peaks in the frequency domain data.

In an embodiment, the selected subset of frequency domain data corresponds to the highest <NUM> frequency peaks in the frequency domain data.

In an embodiment, the sensor device is also arranged to transmit other data in addition to the selected subset of frequency domain data.

In an embodiment, the amount of other data is determined according the amount of data that can be included in a single data packet.

In an embodiment, the other data includes any one or more of the following:.

In an embodiment, the sensor is arranged to produce time domain vibration data representative of vibrations adjacent the vibration sensor.

In an embodiment, the sensor is arranged to produce time domain acceleration data, time domain velocity data and/or time domain displacement data.

In an embodiment, the LPWAN protocol is a LoRaWAN protocol.

In an embodiment, the sensor device includes an external memory separate to the signal processing component and the data transmission component, the sensor device arranged to store the time domain data in the external memory and to load the time domain data into the signal processing component for processing. The sensor device may be arranged to load successive portions of the time domain data into the signal processing component so that the time domain data can be processed in several batches.

In an embodiment, the selected subset of frequency domain data is selected from a defined frequency band.

The at least one sensor device component may comprise the sensor, at least one sensor port, an external memory separate to the signal processing component and the data transmission component, and/or a reprogramming port. According to the invention, the sensor device comprises a power manager arranged to control provision of power to at least one sensor device component based on defined power management criteria.

In an embodiment, the sensor device includes at least one power switch responsive to an activation signal from the power manager, the power switch arranged to cause power to be provided to at least one of the sensor device components in response to the activation signal and to cause power to not be provided to at least one of the sensor device components in absence of the activation signal. The at least one power switch may comprise at least one FET that may be a MOSFET.

In an embodiment, the power manager is arranged to control transmission of frequency domain data by the data transmission component according to defined criteria so as to control usage of the data transmission component.

In an embodiment, the power manager is arranged to progressively fill a buffer with data until the amount of data in the buffer is sufficient to fill a payload of a data packet used by the data transmission component, and to cause the data in the buffer to be sent by the data transmission component when sufficient data is present in the buffer.

In an embodiment, the power manager is arranged to send the data irrespective of whether there is sufficient data to fill a data packet if at least one defined criterion is met.

The at least one defined criterion may include a maximum and/or minimum permissible value associated with a sensor, and the power manager may be arranged such that if a current value associated with the sensor exceeds the maximum or minimum value, the current value is transmitted.

The at least one defined criterion may include a maximum permissible difference value associated with a sensor, the permissible difference value representing a difference amount between a current value and a corresponding previous value, and the power manager arranged such that if a current difference value exceeds the maximum difference value, the current value is transmitted.

In an embodiment, the sensor device is arranged to transmit a heartbeat communication to indicate that a monitored component is operating as expected based on received sensor values, and to send frequency domain data if the at least one defined criterion is met.

In an embodiment, the signal processing component is arranged to carry out a fast Fourier transform (FFT) process to produce FFT data using the time domain data.

The sensor device may comprise a sampler arranged to produce time domain data samples, the signal processing component arranged to use the time domain data samples to produce frequency domain data indicative of frequency components present in the time domain samples.

In an embodiment, the sensor device comprises at least one further sensor, the data transmission component arranged to transmit at least a portion of sensor data derived from the at least one further sensor. The at least one further sensor may include a temperature sensor.

In an embodiment, the sensor comprises an accelerometer that may be arranged to sense vibrations in <NUM> mutually orthogonal axes.

In an embodiment, the accelerometer is arranged to produce time domain data indicative of acceleration, velocity or displacement.

In an embodiment, the sensor device includes a processor that may form part of a system on chip (SoC) device, the SoC device including the data transmission component.

In an embodiment, the sensor device comprises a decoder to multiplex between data inputs of the SoC device and components of the sensor device.

In an embodiment, the sensor device includes a machine-readable code indicative of a unique identifier associated with the sensor device. The machine-readable code may include a QR code.

In an embodiment, components of the sensor device are encapsulated such that the components are isolated from ambient conditions.

In an embodiment, the sensor device includes an intrinsically safe switch arranged to control provision of power from a battery to all electrical components of the sensor device. The intrinsically safe switch may include a reed switch and a magnet that is receivable in a recess disposed adjacent the reed switch, wherein when the magnet is not received in the recess, the reed switch is closed, and when the magnet is received in the recess, the magnetic force provided by the magnet causes the reed switch to open.

In an embodiment, the sensor device comprises at least one magnetic portion, such as a magnetic foot, for attaching the sensor device to an industrial facility component.

In accordance with a second aspect of the present invention, there is provided a sensor network comprising:.

In accordance with the present invention, there is provided a method of sensing an operational characteristic of a component using a sensor device according to claim <NUM>.

Referring to the drawings, in <FIG> there is shown a sensor device <NUM> suitable for use in an industrial facility to obtain operational characteristics of a component in the industrial facility, in this example vibration and temperature characteristics of a component in an LNG plant. Such components may include, for example, components that incorporate at least one moving part including compressors, pumps, motors and fans; heat exchangers; switch gear; and structural monitoring devices. Other operational characteristics may in addition or alternatively be obtained, including velocity and/or displacement of a component.

The sensor device <NUM> includes a housing <NUM> that encapsulates components of the sensor device such that the components are isolated from ambient conditions, and a plurality of feet <NUM>, in this example <NUM>, that in this example are magnetic to facilitate magnetic attachment of the sensor device <NUM> to a component in the industrial facility that has a characteristic desired to be monitored. As an alternative to magnetic attachment, it will be understood that the sensor device <NUM> may be attached to an industrial facility component in any other way, for example using cable ties.

In this example, identification indicia is disposed on the housing <NUM> to uniquely identify the sensor device, for example as part of a commissioning process wherein it is desirable to associate the sensor device <NUM> with the particular industrial facility component that the sensor device will monitor. In this example, the identification indicia include a machine-readable code such as a QR code <NUM>.

The sensor device <NUM> also includes an intrinsically safe switch <NUM> that serves to activate or deactivate the sensor device by connecting power to or disconnecting power from components of the sensor device <NUM>. In this example, the intrinsically safe switch <NUM> includes a reed switch <NUM> and an elongate magnet <NUM> that is receivable in an elongate recess <NUM> disposed adjacent the reed switch <NUM>. The arrangement is such that when the magnet <NUM> is not received in the recess <NUM>, the reed switch <NUM> is closed, and when the magnet <NUM> is received in the recess <NUM>, the magnetic force provided by the magnet causes the reed switch <NUM> to open.

It will be understood that the intrinsically safe switch <NUM> enables the sensor device components to remain encapsulated and isolated from ambient whilst providing an effective arrangement for activating and deactivating the sensor device by a user.

In an alternative arrangement, instead of using the reed switch <NUM> and magnet <NUM> to facilitate activation and deactivation of the sensor device, the sensor device may include a mechanical switch and a MOSFET, for example with the switch current limited using resistors of a voltage divider.

A sensor network <NUM> showing a plurality of sensor devices 10a, 10b disposed at multiple industrial facilities, in this example <NUM> industrial facilities 32a, 32b, is shown in <FIG>.

Each industrial facility 32a, 32b includes multiple industrial facility components 34a, 34b, each of which has an associated sensor device 10a, 10b attached to the industrial facility component, in this example using the magnetic feet <NUM>.

Each sensor device 10a, 10b communicates with a gateway 36a, 36b arranged to receive wireless communications from multiple sensor devices 10a, 10b and to communicate wirelessly with a local server 40a, 40b, in this example through a firewall 38a, 38b. Each local server 40a, 40b then communicates, for example in a conventional way, through a wide area network such as the Internet <NUM> with a common remote analysis facility <NUM> that for example may be used to analyse data received from the sensor devices 10a, 10b.

In this example, the analysis facility <NUM> includes a firewall <NUM> and a remote server <NUM> accessible either directly by a local terminal <NUM> or remotely, for example through the Internet <NUM>, by a remote terminal <NUM>.

The communications network at each industrial facility 32a, 32b is configured according to a low power wide area network (LPWAN) that is arranged to facilitate long range communications at low power (but at a low bit rate). LPWAN typically has a range up to <NUM>, has a bit rate of about <NUM>. 3kbit/s to 50kbit/s per channel, and LPWAN based devices can typically operate for <NUM> years or more before battery replacement is required. In the present example, a low power, long range, readily scalable LoRaWAN wireless communication network protocol is used, although it will be understood that other LPWAN protocols may be used.

LoRaWAN in Australia operates using a <NUM>-<NUM> carrier frequency. A communications network using the LoRaWAN protocol is capable of communicating over distances of the order of <NUM> and LoRaWAN signals more readily travel through a dense, metallic environment than for example <NUM>. 11x protocol signals. In addition, the LoRaWAN protocol uses spread signal chirp technology that allows thousands of nodes to be connected to each gateway, which provides a network that is highly scalable compared to, for example, <NUM>. 11x, LTE and <NUM>. <NUM> protocols.

In addition, since a device that uses a LPWAN protocol uses significantly less power than a device that uses for example an <NUM>. 11x, LTE or <NUM>. <NUM> protocol, the power consumption of the present sensor devices 10a, 10b is significantly less than related sensor devices known hitherto.

Furthermore, since components of a communications network that uses a LPWAN protocol are significantly less expensive than components required for an <NUM>. 11x, LTE or <NUM>. <NUM> network, the present sensor devices 10a, 10b are significantly less expensive than related sensor devices known hitherto.

However, since LPWAN uses a significantly lower frequency than for example <NUM>. 11x, the bandwidth available to the sensor device <NUM> to transmit data is significantly reduced relative to <NUM>.

Referring to <FIG>, components <NUM> of the sensor device <NUM> are shown. Interconnections between the components <NUM> include data connections <NUM> and power connections <NUM>.

The components <NUM> include a communications system on a chip (SoC) device <NUM> that has a processor <NUM> and associated internal memory <NUM>, and a radio frequency modem <NUM> arranged to wirelessly send RF signals to and wirelessly receive RF signals from a gateway <NUM>. In this example, the SoC device <NUM> is a Multitech xDot device that includes an Arm Cortex <NUM> microcontroller, although it will be understood that any suitable SoC device is envisaged.

A SoC was selected that has very low power usage characteristics, but a consequence of this is that the amount of internal memory <NUM> is too small to handle the desired number of vibration data samples. For this reason, external memory <NUM> is also included.

The components <NUM> include a battery <NUM> that in this example is a <NUM>. 7V battery, and a battery monitoring device <NUM> arranged to monitor the battery voltage and for example to send a communication indicative of the battery voltage, for example periodically, to the analysis facility <NUM>.

The components <NUM> also include the intrinsically safe switch <NUM> arranged to control communication of an activation signal to a first power switch <NUM> that in response to receipt of the activation signal provides power from the battery <NUM> to the processor <NUM>, the RF modem <NUM> and a decoder <NUM>.

In this example, the first power switch <NUM> comprises a FET device such as a MOSFET.

Similarly, a second power switch <NUM> is responsive to an activation signal from the processor <NUM> such that in response to receipt of the activation signal, the second power switch <NUM> provides power from the battery <NUM> to an accelerometer <NUM>, a temperature sensor <NUM>, an external memory <NUM>, a reprogramming port <NUM>, a first sensor port <NUM> and a second sensor port <NUM>.

In this example, the second power switch <NUM> comprises a FET device such as a MOSFET.

It will be understood that while the SoC device <NUM> has very low inherent power usage characteristics, the power usage profile of the sensor device <NUM> is maintained at a low level by actively removing power from components of the sensor device <NUM> using the second power switch <NUM> when the components are not being used.

Based on the type of selected SoC device <NUM> and the power management arrangements of the sensor device <NUM>, it is envisaged that the present sensor device <NUM> will have a productive life of the order of <NUM> years.

The decoder <NUM> is included so that the effective number of ports connected to the SoC device <NUM> can be increased, the decoder <NUM> functioning as a multiplexer between data inputs of the SoC device <NUM> and the accelerometer <NUM> / the external memory <NUM> / the first sensor port <NUM> / and the second sensor port <NUM>. The decoder <NUM> may use a Chip Select control line of the processor <NUM> to control the multiplexing function of the decoder <NUM>.

The accelerometer <NUM> is arranged to sense vibrations and to generate a signal indicative of the vibrations. In this example, the accelerometer <NUM> senses vibrations in <NUM> mutually orthogonal axes and produces <NUM> signals indicative of x, y and z orthogonal vibrations. The signals indicative of the vibrations may be signals indicative of acceleration, velocity and/or displacement, in this example in <NUM> mutually orthogonal directions.

In this example, the accelerometer <NUM> is an ADXL345 MEMS based accelerometer, although it will be understood that any suitable accelerometer is envisaged.

Data indicative of the raw vibration signals received from the accelerometer <NUM> is, under control of the processor <NUM>, temporarily stored in the external memory <NUM>, the vibration data being subsequently loaded into the processor internal memory <NUM> so that a fast Fourier transform (FFT) process can be carried out on the vibration data by the processor <NUM>. In this example, the FFT process carried out is based on about <NUM>,<NUM> vibration data points obtained by sampling the raw vibration signals produced by the accelerometer <NUM>.

It will be understood that on-board FFT analysis by the sensor device <NUM> is necessary because the bandwidth associated with the LPWAN, in this example LoRaWAN, protocol is low to the extent that it would not be possible to transmit the large amount of sampled vibration data, but the bandwidth is sufficient to transmit data indicative of the results of the FFT analysis. Accordingly, implementation of the FFT analysis on the sensor device <NUM> enables an information rich relatively small data set to be transmitted. In this example, the transmitted data set is of the order of <NUM> bytes as this is the size of a LoRaWAN packet payload.

In this example, the temperature sensor <NUM> is a DS18B20 temperature sensor, although it will be understood that any suitable temperature sensor is envisaged.

In this example, the external memory <NUM> is 4Mb of SRAM, SRAM being used because SRAM is volatile and is capable of withstanding a large number of writes, unlike Flash memory, although it will be understood that any suitable external memory is envisaged.

The reprogramming port <NUM> is used to communicate directly with the sensor device <NUM>, for example so as to reprogram the SoC device <NUM>.

The first and second sensor ports <NUM>, <NUM> are for connection to other sensors, for example an audio sensor.

Referring to <FIG>, functional components <NUM> of or implemented by the processor <NUM> are shown. The processor <NUM> includes associated temporary memory <NUM> used to implement processes and temporarily store data. The processor <NUM> also implements processes, for example using programs stored in non-volatile memory (not shown).

The functional components <NUM> implemented by the processor <NUM> include:.

The functional components <NUM> also include configuration settings <NUM>, for example that relate to:.

In this example, the settings define that the data indicative of temperature is captured periodically, such as every <NUM> minutes, although it will be understood that any suitable data capture timing regime is envisaged.

In this example, the settings define that the samples of vibration data are captured periodically, such as every <NUM> minutes, although it will be understood that any suitable data capture timing regime is envisaged. In this example, the sampling rate is about <NUM>, although it will be understood that any suitable sampling rate is envisaged.

In this example, the FFT implementer <NUM> uses a Cooley-Tukey algorithm, although it will be understood that any suitable FFT algorithm is envisaged.

In this example, the set of data derived from the FFT vibration data for transmission by the RF modem <NUM> is selected based on a defined number of frequency peaks, for example the <NUM> highest frequency peaks in the FFT vibration data, although it will be understood that any suitable criterion may be used to select the set of data from the FFT vibration data for transmission. For example, the set of data may be selected based on a defined number of frequency peaks within a defined frequency band. Alternatively, the set of data for transmission may be based on defined criteria, such as all peaks above a defined value up to a maximum number of peaks.

In this example, after activation of the sensor device <NUM> by removal of the magnet <NUM> from the recess <NUM>, power management of the sensor device <NUM> is controlled by the second power switch <NUM> based on the power management characteristics managed by the processor <NUM>. The power management characteristics may define that power is provided to the accelerometer <NUM>, the temperature sensor <NUM>, the external memory <NUM>, the reprogramming port <NUM>, the first sensor port <NUM> and the second sensor port <NUM> only when an action is required to be carried out by any one of these components. For example, the power management characteristics may define that power is provided to the components when the configuration settings indicate that temperature and vibration data is required to be captured, and power is removed from the components after the temperature data and FFT vibration data are transmitted by the RF modem <NUM>.

Examples of raw vibration data and FFT vibration data are shown in <FIG> and <FIG>.

<FIG> show raw sample vibration data captured from the accelerometer <NUM>. <FIG> shows raw sample vibration data in an x-axis, <FIG> shows raw sample vibration data in a y-axis, and <FIG> shows raw sample vibration data in a z-axis.

<FIG> show FFT data obtained from the raw sample vibration data shown in <FIG>. <FIG> shows FFT data in an x-axis, <FIG> shows FFT data in a y-axis, and <FIG> shows FFT data in a z-axis.

In this example, for each of the FFT x, y and z axis data, the data corresponding to the <NUM> highest peaks is selected and transmitted using the RF modem <NUM> to the remote analysis facility <NUM>.

At the remote analysis facility <NUM>, the received selected FFT data and received temperature data can be used to analyse the vibration and temperature characteristics of the monitored components <NUM>, for example in order to determine whether any problems exist in relation to the components <NUM>.

Depending on the type of sensor used, or depending on the configuration used for the sensor, the received FFT data may be indicative of acceleration, velocity or displacement.

It will be understood that the remote analysis facility <NUM> in this example is arranged to monitor operational characteristics of components <NUM> associated with multiple industrial facilities <NUM>, and in this way by using appropriate software at the remote analysis facility <NUM>, it is possible to develop useful data indicative of operational trends that may enable operators to improve aspects of the industrial facility.

The sensor device <NUM> is constructed in order to comply with IECEx certification requirements by including the following features:.

In the present embodiment, in order to further minimise power usage, the sensor device <NUM> may be arranged to transmit the data based on defined criteria so that usage of the RF modem <NUM>, which is a relatively high draw on power, is minimised. For example, rather than transmitting data immediately after data is collected, the power manager <NUM> may be arranged to maintain a buffer of data, for example implemented in the CPU <NUM>, and to progressively fill the buffer until the amount of data in the buffer is sufficient to fill the payload of a LoRaWAN packet. After the required packet length has been achieved, the power manager <NUM> causes the data to be sent.

In the present embodiment, FFT vibration data is transmitted immediately after it is obtained, and temperature data is used to fill the buffer and is only sent when the buffer is full.

In a variation to this arrangement, the power manager <NUM> may nevertheless be arranged to send data as it is created if at least one defined criterion is met irrespective of whether there is sufficient data to fill a LoRaWAN packet.

For example, a record of maximum and minimum permissible temperature values may be stored and the power manager <NUM> arranged such that if detected temperature data values exceed the maximum or minimum values, the current temperature data is transmitted.

Similarly, a record of maximum permissible FFT vibration or temperature difference values may be stored, the permissible difference values representing difference amounts between the current values and corresponding previous values. With this example, the power manager <NUM> may be arranged such that if difference values exceed a maximum difference value, the current data is transmitted. In addition, with this arrangement, the sensor device <NUM> may be arranged to transmit a heartbeat communication if the difference threshold is not exceeded to indicate to the analysis facility <NUM> that the monitored component is operating as expected, with data only transmitted if the threshold is exceeded, to indicate that component characteristics have notably changed.

Referring to <FIG>, a flow diagram <NUM> illustrating an example process of operation of a sensor device <NUM> is shown.

Based on the data capture and power management configuration settings <NUM> that define a wake up time, the processor <NUM> sends an activation signal to the second power switch <NUM> to cause the sensor device <NUM> to wake <NUM>, by causing power to be provided to the accelerometer <NUM>, the temperature sensor <NUM>, the external memory <NUM>, the reprogramming port <NUM>, the first sensor port <NUM> and the second sensor port <NUM>. After waking, the processor <NUM> reads <NUM> the stored configuration settings <NUM> to determine the settings to use for capture of the temperature and vibration data from the temperature sensor <NUM> and the accelerometer <NUM>, and using the settings the temperature data and samples of the raw <NUM>-axis vibration data are obtained <NUM>, <NUM>, <NUM> and stored <NUM> in the external memory <NUM>.

At least some of the components, of the sensor device <NUM>, including the accelerometer <NUM>, may include an input responsive to a sleep signal such that although power is still provided to the component, in response to receipt of the sleep signal, the component is placed in a sleep state so that the component uses less power.

In the present example, the accelerometer <NUM> is placed in a sleep state <NUM> after accelerometer signal have been captured.

The processor <NUM>, using the data handler <NUM>, loads <NUM> successive portions of the raw vibration data into the internal memory <NUM> from the external memory <NUM>, and using the FFT implementer <NUM>, carries out <NUM> a FFT process on the raw vibration data to produce FFT vibration data. The FFT vibration data is stored <NUM> in the external memory.

Using the stored FFT vibration data, data is selected <NUM> from the stored FFT data based on the defined FFT characteristics in the configuration settings <NUM>, and the selected FFT data is transmitted to the remote analysis facility <NUM> using a LoRaWAN protocol by the RF modem <NUM>.

After receipt of the selected FFT data from the sensor device <NUM> by the remote analysis facility <NUM>, the remote analysis facility <NUM> may take the opportunity to send instructions to the sensor device <NUM> while the sensor device <NUM> is awake. For example, the instructions may include new configuration data to change sample times, wake/sleep times, sample rates, and so on, or the instructions may include instructions to reboot the sensor device <NUM>. Any received new configuration data is stored <NUM>, and based on the power management configuration settings <NUM> that define a sleep time, the processor <NUM> sends a deactivation signal to the second power switch <NUM> to cause the sensor device <NUM> to sleep <NUM> until the next scheduled wake time.

The above embodiments are described in relation to an arrangement wherein FFT frequency domain data is obtained from time domain vibration data, and a subset of the FFT data is selected for transmission by the RF modem <NUM>, such as a defined number (such as <NUM>) of the highest peaks in the frequency domain data. Such data may be sent in each LPWAN packet. For example, the LPWAN packet may comprise about <NUM> bytes that includes the data shown in the following table.

It will be understood that with this arrangement, after capture of data from the sensor <NUM>, the data may typically be transmitted in a single LPWAN packet, and as a consequence power consumption by the sensor <NUM> is low. However, notwithstanding that data associated with each data capture instance is typically transmitted using a single LPWAN packet, in some circumstances more than one packet may be transmitted, depending on the data that is required to be sent.

In an alternative embodiment, the selected subset of FFT data may include a different number of the highest peaks, and/or a different number of bytes used to communicate the peak data. For example, the inventors have realised that <NUM>/s<NUM> is a sufficiently high maximum value for acceleration amplitude in the frequency domain data, and consequently it is possible to use a lower number of bytes to represent the amplitude data in a LPWAN packet. Since with this example <NUM> bytes are used for the peak amplitude data instead of <NUM>, it is possible to include in each LPWAN packet additional data that is derivable from the captured time domain vibration data because <NUM> bit is available in the LPWAN packet for each frequency peak in the data.

For example, a LPWAN packet may include data indicative of any one or more of the following:.

An embodiment that transmits the above data may include a LPWAN packet that includes the data shown in the following table.

It will therefore be understood that additional information is sent with this arrangement even though only a single LPWAN packet is still typically transmitted with each data capture instance.

However, it will be understood that any suitable data derivable at the sensor from the time domain and/or frequency domain data may be included in a LPWAN packet.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

Claim 1:
A sensor device (<NUM>) comprising:
a sensor (<NUM>, <NUM>) controlled to produce time domain data representative of a sensed time dependent characteristic adjacent the sensor;
a signal processing component (<NUM>) comprising:
- an FFT-implementer (<NUM>) arranged to use the time domain data to produce frequency domain data indicative of frequency components present in the time domain data;
the sensor device comprising
- a data transmission component (<NUM>) arranged to transmit a portion of the frequency domain data using a LPWAN protocol; characterized in that the signal processing component (<NUM>) further comprises:
- a power manager (<NUM>) arranged to control provision of power to at least one sensor device component of said sensor device (<NUM>) based on defined power management criteria, the power management criteria defining wake up and sleep times whereby power to the at least one sensor device (<NUM>) component is caused to be connected during wake time and power to the at least one sensor device (<NUM>) component is caused to be disconnected during sleep time;
and in that the sensor device (<NUM>) is arranged to:
select a subset of frequency domain data from the frequency domain data, based on defined Fast Fourier Transform characteristics in a configuration setting of the sensor device (<NUM>); and
transmit the selected subset of frequency domain data in a single data packet using the LPWAN protocol.