ELECTRONIC DEVICE WITH DEFORMATION DETECTION WAKE-UP CIRCUIT

Abstract

Electronic device with a wake-up circuit by strain detection. This description relates to an electronic device (100) configured to operate in at least one standby state or one awake state, comprising at least: - a strain sensor (102) comprising at least one portion of piezoelectric material (103) with a thickness of less than 50 µm; - a wake-up circuit (104) comprising at least one comparator (110) configured to compare a value obtained from a measurement signal of the strain sensor (102) with a wake-up threshold value and to output a wake-up signal of the electronic device (100) when the value obtained from the measurement signal is greater than the wake-up threshold value. Figure for the abbreviation: Fig. 1

Description

Title of the invention: Electronic device with a deformation detection wake-up circuit technical field

[0001] This description relates generally to the field of monitoring, in particular vibration monitoring or more generally deformation monitoring, applied for example to structures, infrastructures, machines, etc. Previous technique

[0002] It is possible to monitor the fatigue state of a structure or infrastructure, such as a building or a pipeline network, or even the condition of a machine, using IoT (Internet of Things) beacons, or wirelessly connected sensors. Such a beacon generally comprises one or more sensors, possibly a circuit for analyzing the measurements taken, and a wireless communication circuit. One of the major constraints for these beacons is to maximize their battery life to ensure the longest possible lifespan. This is achieved in particular by optimizing the management of the beacons' standby phases, or states or modes, during which the beacons' functionalities are limited to reduce energy consumption, and their active or wake-up phases, during which the beacons are fully functional.

[0003] One possible approach to managing the sleep and wake phases of a beacon involves periodically waking it up arbitrarily and implementing a measurement during the wake phase to see if a monitored event, such as vibrations, is occurring. If the event is occurring, measurements of that event are taken. Otherwise, the beacon is returned to sleep. However, this approach is not efficient because many wake-ups of the beacon may be unnecessary when the monitored event does not occur. Furthermore, the beacon may be in a sleep state when the monitored event occurs, i.e., at a time when implementing measurements would have been relevant.

[0004] A second possible method for managing the sleep and wake-up phases of a beacon involves using a low-power local detection device. For example, when the event to be monitored is the occurrence of vibrations in the element to which the beacon is attached, the beacon can be equipped with an accelerometer designed to detect an acceleration related to these vibrations and to wake the beacon if such an acceleration is detected. However, this method has the drawback that the accelerometer has This solution results in a continuous and potentially significant electrical power consumption, for example, exceeding 10 pA. Furthermore, the acceleration threshold at which the accelerometer activates the beacon is fixed and cannot be easily modified. Finally, this solution introduces a significant delay between the accelerometer detecting acceleration and the beacon activating and performing the desired measurement, because converting an acceleration measurement to a corresponding deformation value requires two integrations of the measured acceleration value.

[0005] These disadvantages can also be found in other types of electronic devices that have to manage wake-up and standby phases. Summary of the invention

[0006] There is a need to propose an electronic device that can be in a standby state and whose management of standby and wake-up phases does not pose the problems of existing devices.

[0007] One embodiment overcomes all or part of the drawbacks of known solutions and proposes an electronic device configured to operate at least in a standby state or in an awake state, comprising at least:

[0008] - a strain sensor comprising at least a portion of material piezoelectric with a thickness of less than 50 pm;

[0009] - a wake-up circuit comprising at least one comparator configured to compare a value obtained from a measurement signal from the strain sensor with a wake-up threshold value and output a wake-up signal from the electronic device when the value obtained from the measurement signal is greater than the wake-up threshold value.

[0010] In a particular embodiment, the portion of piezoelectric material comprises a piezoceramic material.

[0011] In a particular embodiment, the electronic device corresponds to a deformation measurement device and further includes a measurement acquisition circuit configured to receive as input and process the measurement signal from the deformation sensor, or a signal from the measurement signal from the deformation sensor, when the electronic device is awake.

[0012] In a particular embodiment, the measurement acquisition circuit comprises at least:

[0013] - a signal processing circuit for measuring the deformation sensor or the signal derived from the measurement signal of the deformation sensor;

[0014] - a wake-up control circuit configured to receive as input the signal from wake-up and the measurement signal from the strain sensor, or to receive as input the wake-up signal and the signal from the measurement signal of the deformation sensor, and to control, upon receipt of the wake-up signal, the sending of the measurement signal of the deformation sensor or the signal from the measurement signal of the deformation sensor to the input of the processing circuit and the power supply of the processing circuit.

[0015] In a particular embodiment, the wake-up control circuit includes at least one microcontroller configured to operate in a low-power mode when the electronic device is in standby.

[0016] In a particular embodiment, the wake-up control circuit includes at least one transmission gate comprising at least one data input configured to receive the measurement signal from the strain sensor or the signal from the measurement signal from the strain sensor, at least one output coupled to an input of the processing circuit, and at least one control input coupled to an output of the microcontroller.

[0017] In a particular embodiment, the processing circuit includes at least one amplifier, and at least one switch configured to control the power supply of the amplifier according to a control signal intended to be emitted by the microcontroller and such that the amplifier is not powered when the electronic device is in standby.

[0018] In a particular embodiment, the processing circuit further comprises at least one analog-to-digital converter and / or at least one anti-aliasing filter.

[0019] In a particular embodiment, the electronic device further comprises at least one wireless communication circuit configured to transmit over a wireless network data obtained from an output signal of the processing circuit.

[0020] In a particular embodiment, the electronic device further comprises a wake-up threshold circuit which is programmable and configured to apply the wake-up threshold value to the comparator input, and in which the wake-up threshold value is defined as a function of a value received by the wireless communication circuit.

[0021] In a particular embodiment, the electronic device is configured to switch the microcontroller from low power mode to active mode upon receiving a new wake-up threshold value through the wireless communication circuit, then to update the wake-up threshold circuit with the new threshold value received, and then to switch the microcontroller from active mode to low power mode.

[0022] In a particular embodiment, the electronic device is configured to turn on the switch and to switch the microcontroller from a low-power mode to an active mode when the value of the measurement signal from the strain sensor or the signal derived from the measurement signal from the strain sensor becomes greater than the wake-up threshold value, and then begin the acquisition of the measurement signal from the strain sensor or the signal from the measurement signal from the strain sensor, then stop the acquisition when the value of the measurement signal from the strain sensor or the signal from the measurement signal from the strain sensor becomes less than the wake-up threshold value, then calculate and transmit data obtained from the acquisition performed, then to switch the microcontroller from active mode to low power mode and put the switch in the blocked state.

[0023] In a particular embodiment, the wake-up circuit further comprises a biasing circuit configured to receive as input the measurement signal from the strain sensor and to bias the measurement signal from the strain sensor and deliver on an input of the comparator an output signal representative of the absolute value of the measurement signal from the strain sensor.

[0024] In a particular embodiment, the electronic device further includes a power supply battery.

[0025] A vibration monitoring system is also described, comprising at least one electronic device as described herein and computer equipment to which said at least one electronic device is connected via a computer network. Brief description of the drawings

[0026] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0027] - [Fig. 1] schematically represents an example of an electronic device according to a particular method of implementation;

[0028] - Figure 2 schematically represents an example of an embodiment of the device electronic according to a particular embodiment;

[0029] - Figure 3 schematically represents an example of the implementation of a circuit polarization of the electronic device;

[0030] - Figure 4 schematically represents an example of an amplifier implementation of the electronic device;

[0031] - Fig. 5 schematically represents an example of the implementation of an anti-filter folding of the electronic device;

[0032] - [Fig. 6] represents a logic diagram implemented by an electronic device according to a particular embodiment;

[0033] - Figure 7 shows examples of signals obtained during a wake-up and a measurement of deformation carried out by an electronic device according to a particular embodiment. Description of the implementation methods

[0034] The same elements may be designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0035] For the sake of clarity, only the steps and elements necessary for understanding the described embodiments and examples have been shown and are detailed. In particular, various elements and circuits of the electronic device (strain sensor, microcontroller, analog-to-digital converter, wireless communication circuit, etc.) are not detailed. A person skilled in the art will be able to implement these elements in detail from the functional description given here.

[0036] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") together, this means that these two elements can be connected or linked through one or more other elements.

[0037] Unless otherwise specified, the expressions "approximately", "roughly", and "in the order of" mean within 10%, preferably within 5%.

[0038] An example of an electronic device 100 according to a particular embodiment is described below in relation to [Fig.1].

[0039] In the example described, the device 100 corresponds to a deformation measurement device configured to monitor a deformation of an element and / or the appearance of vibrations of the element which may be a structure, an infrastructure, a machine, etc.

[0040] Advantageously, the device 100 corresponds to a loT beacon used within a monitoring system, for example a vibration monitoring system, comprising at least one such loT beacon and at least one computer equipment to which the beacon(s) are wirelessly connected through a computer network.

[0041] In order to limit its power consumption, the device 100 is configured to operate in different operating states. In the particular embodiment described here, the device 100 can be either in a standby state or in an awake or active state. Alternatively, the device 100 can have other operating states, such as one or more deep or intermediate sleep states.

[0042] The device 100 comprises at least one strain sensor 102. The sensor 102 comprises at least one portion of piezoelectric material 103 whose thickness is less than 50 pm, preferably less than 25 pm, and even more preferably less than 10 pm. For example, the value of the ratio between the thickness and the width, and / or the thickness and the length, of this portion of piezoelectric material 103 is for example less than 0.1, preferably less than 0.05, and even more preferably less than 0.01.

[0043] In the described embodiment, the piezoelectric material of portion 103 corresponds to a piezoceramic material, for example PZT (lead zirconate titano), or LiNbO3 (lithium niobate), or LiTaO3 (lithium tantalate). Other piezoelectric materials are also conceivable for the realization of portion 103, such as BaTiO3 (barium titanate), PbTiO3 (lead titanate), KNbO3 (potassium niobate), NBT (NaO25BiO25TiO3 or sodium bismuth titanate), BiFeO3 (bismuth ferrite), ZnO (zinc oxide), PAIN (aluminum nitride) or BNT (BiO25NaO25TiO3 or sodium bismuth titanate) or a crystal such as quartz, or even a polymeric piezoelectric material such as PVDF.

[0044] Other details of the realization of such a sensor 102 are described for example in the document by T.Dufay et al., “Flexible PZT thin film transferred on polymer substrate”, Surface and Coatings Technology, Elsevier, 2018, 343, pp. 148-152.

[0045] In the example of [Fig. 1], the portion of piezoelectric material 103 of the sensor 102 is arranged between a first electrode coupled to a reference electrical potential and a second electrode on which a measurement signal called "ch_in" is delivered at the output of the sensor 102.

[0046] The device 100 further includes a wake-up circuit 104 whose function is to detect, with high precision, the occurrence of a deformation triggering the transition from the standby state to the awake state of the device 100. The wake-up circuit 104 is configured to operate with very low power consumption.

[0047] In the example of [Fig. 1], the wake-up circuit 104 includes a biasing circuit 106 configured to receive as input the measurement signal ch_in from the sensor 102 and to bias this signal so as to obtain at the output of the biasing circuit 106 an output signal, here a voltage, called "voltage_out", which is representative of the absolute value of the measurement signal ch_in. In the described embodiment, the biasing circuit 106 is used to allow a comparison of the measurement signal ch_in to a reference value regardless of the sign of the measurement signal ch_in, since the measurement signal ch_in can be positive or negative depending on the deformation to which the sensor 102 is subjected.

[0048] Alternatively, it is possible that the wake-up circuit 104 does not include the biasing circuit 106.

[0049] Following the example of [Fig. 1], the wake-up circuit 104 further includes a wake-up threshold circuit 108 configured to deliver at output a wake-up threshold value called "vth", here a voltage, to which the output signal voltage_out is intended to be compared to determine whether the device 100 should be woken up and exit the sleep state.

[0050] Advantageously, the wake-up threshold circuit 108 is programmable and the wake-up threshold value vth can be defined as a function of a value received by the wake-up threshold circuit 108, for example wirelessly.

[0051] Although not shown in [Fig. 1], the device 100 described in this example includes a wireless communication circuit configured to transmit and receive data over a wireless network. When the wake-up threshold circuit 108 is programmable, the wake-up threshold value vth delivered by the wake-up threshold circuit 108 may have been initially received by the wireless communication circuit. Different communication protocols and / or standards may be used for the data exchanges implemented with the device 100. Alternatively, the device 100 may communicate via a wired connection.

[0052] The wake-up circuit 104 further includes a comparator 110 configured to compare the value of the output signal voltage_out to the wake-up threshold value vth and output a wake-up signal called "wake_up" of the device 100. The value of this signal triggers the device 100 to wake up when the value of the output signal voltage_out is greater than the wake-up threshold value vth. For example, the wake_up signal may have a non-zero value when the device 100 needs to transition from standby to wake-up mode. When the wake-up circuit 104 does not include the biasing circuit 106, the comparator 110 can perform a comparison between the measurement signal ch_in and the wake-up threshold value vth.

[0053] In the particular embodiment described, the device 100 corresponds to a deformation measuring device in which the measurement signal ch_in from the sensor 102 serves both as a wake-up function and for the precise measurement of the deformation to be evaluated by the device 100. For this purpose, the device 100 further comprises a measurement acquisition circuit 112 for receiving as input the wake-up signal wake_up and the measurement signal ch_in. The measurement acquisition circuit 112 is designed to process the measurement signal ch_in when the device 100 is in the awake state. At least some of the elements of the measurement acquisition circuit 112 are designed to be woken up and / or electrically powered when the device 100 transitions from the sleep state to the awake state.

[0054] Alternatively, the measurement acquisition circuit 112 could receive the output signal voltage_out as input instead of the measurement signal ch_in.

[0055] As an alternative to the particular embodiment described, it is possible that the device 100 is not configured to process the deformation measurement obtained by the sensor 102, but serves only to wake up another device, for example a camera, another sensor, etc. In this case, the device 100 may not include the measurement acquisition circuit 112.

[0056] In the example of [Fig. 1], the measurement acquisition circuit 112 includes a processing circuit 114 configured to process the measurement signal ch_in when the device 100 is in the awake state.

[0057] In the example described, the processing circuit 114 comprises an amplifier 116 configured to receive as input the measurement signal ch_in, an anti-aliasing filter 118 configured to receive as input the amplified measurement signal obtained at the output of the amplifier 116, and an analog-to-digital converter 120 configured to receive as input the amplified and filtered measurement signal obtained at the output of the filter 118. The type of amplifier 116 used depends on the nature of the signal to be amplified. In the embodiment described here, the amplifier 116 is a load amplifier.

[0058] Alternatively, the processing circuit 114 may include other components or circuits performing one or more additional operations or processing on the measurement signal ch_in.

[0059] Following the example of [Fig. 1], the measurement acquisition circuit 112 also includes a wake-up control circuit 122 configured to receive as input the wake_up signal and the measurement signal ch_in, and to control, upon receipt of a value of the wake-up signal indicating that the device 100 should switch from the sleep state to the wake-up state, the wake-up of the processing circuit 114.

[0060] As shown in [Fig. 1], the wake-up control circuit 122 comprises a microcontroller 124, a switch 126, and a transmission gate 128. The switch 126 and the transmission gate 128 are controlled by the microcontroller 124. For example, the switch 126 comprises a MOSFET transistor. Furthermore, the transmission gate 128 may comprise at least two MOSFET transistors. When the amplifier 116 is a two-input amplifier, the control circuit 122 may comprise two transmission gates 128, each coupled to one of the inputs of the amplifier 116.

[0061] The microcontroller 124 is configured to receive the wake_up signal as input. When the wake_up signal value indicates that the device 100 should transition from sleep to wake, the microcontroller 124 sends a control signal called "shut_dwn" to the switch 126 to turn it on and activate the power supply to the amplifier 116, and sends another control signal called "voltage_en" to the transmission gate 128 so that this becomes conductive and triggers the sending of the measurement signal ch_in to the input of the amplifier 116. In the example embodiment described, the amplifier 116 is intended not to be electrically powered when the device 100 is in standby.

[0062] Thus, once the device 100 is in the awake state, the deformation experienced by the sensor 102 can be measured by the measurement acquisition circuit 112 until the device 100 returns to standby mode. The measurements obtained can be stored and / or transmitted from the device 100, for example via the wireless communication circuit, to a server or a computer device intended to collect the deformation measurements taken by the device 100. It is also possible that the device 100 includes one or more measurement analysis circuits, and that the transmitted data corresponds not to the measured deformation values, but, for example, to the results of calculations performed based on the measured values.

[0063] An example of an embodiment of device 100 according to a particular embodiment is described below in relation to [Fig.2].

[0064] In this embodiment example, the biasing circuit 106, the amplifier 116, the filter 118, the switch 126 and the transmission gates 128 are made within an analog front-end circuit 130 (AFE, or "Analog Front-End" in English) configured to receive as input the measurement signal ch_in.

[0065] In addition, the comparator 110, the analog-to-digital converter 120, and the microcontroller 124 are implemented within another integrated circuit 132 separate from the AFE 130. In this example, the amplified and filtered measurement signal obtained at the output of the filter 118 is called charge_out and is transmitted from the AFE 130 to the integrated circuit 132. Furthermore, in the described example, the integrated circuit 132 also includes a nested vectored interrupt controller 134 (NVIC, or "Nested Vectored Interrupts Controller") configured to receive the wake_up signal as input and send wake-up instructions from the device 100 to the microcontroller 124 depending on the value of the wake_up signal.In the example described, the circuit 132 further includes a current amplifier 136 configured to supply current while maintaining a stable reference voltage vref to the AFE 130, as well as a digital-to-analog converter 138 that receives the reference voltage vref as input and delivers the wake-up threshold value vth as output. In the example in [Fig. 2], the reference voltage vref is supplied by a reference voltage circuit 140. The elements 136, 138, and 140 can be seen as forming the wake-up threshold circuit 108. The integrated circuit 132 may include other elements such as various memories (RAM, static, dynamic, flash, etc.), computing and communication circuits such as the wireless communication circuit described previously, etc.

[0066] In the example described, the biasing circuit 106 is used in particular when the permissible range of the input voltage on the analog-to-digital converter 120 and / or the comparator 110 is not symmetrical and the measurement signal ch_in must be biased to center its resting value in the middle of the permissible range of the input voltage.

[0067] In the embodiment shown in [Fig. 2], the AFE 130 and the integrated circuit 132 are powered by a voltage Vcc with a value, for example, between 2.7 V and 3.6 V. As can be seen in [Fig. 2], the signals voltage_orL vref, shut_dwn, Vcc, charge_out, and voltage_en are transmitted between the AFE 130 and the integrated circuit 132. In an alternative embodiment, the shut_dwn and voltage_en signals can correspond to a single signal controlling the switch 126 and the transmission gates 128.

[0068] An example of an embodiment of the biasing circuit 106 is shown in [Fig. 3]. In this example, the biasing circuit 106 comprises a resistive bridge including first and second resistors 142, 144, the first electrodes of which are electrically coupled to each other. The reference voltage vre / is applied across the terminals of this resistive bridge formed by the second electrodes of these resistors 142, 144. An output electrode of the sensor 102 is coupled to the first electrodes of the resistors 142, 144, from which the output signal voltage_out is obtained.

[0069] An example of an embodiment of the amplifier 116 is shown in [Fig.4]. In this figure, the amplifier 116 corresponds to a load amplifier.

[0070] In this embodiment of the amplifier 116, a first operational amplifier 146 performs the function of a charge amplifier. A biasing circuit 148 is coupled to the non-inverting input of the first operational amplifier 146 in order to maintain, during the active phase, a bias of the output of the sensor 102 at a value identical to that of the biasing circuit 106 during the inactive phase. This makes it possible to keep the stabilization time of the charge amplifier very short during an inactive / active phase change and vice versa. The output of the sensor 102 is coupled to the inverting input of the first operational amplifier 146, and the electrical charges generated by the sensor 102 are integrated into a feedback capacitor 150 for a time corresponding to the product of the value Ci of the capacitor 150 and the value Ri of a feedback resistor 152 coupled in parallel with the capacitor 150.The resulting gain is 1 / Ci V / C (Volts per Coulomb), and the lower cutoff frequency is equal to 1 / (2*Jt*Ri*Ci). The amplifier example 116 shown in [Fig. 4] also includes a second operational amplifier 154 which performs a common-mode modification to center the quiescent value of the sensor 102 in the middle of the voltage range acceptable to the analog-to-digital converter. 120. This allows digitizing a charge variation, both positive and negative, resulting from a positive or negative deformation of the sensor 102.

[0071] An example of an embodiment of filter 118 is shown in [Fig.5]. In this figure, filter 118 corresponds to an RC low-pass filter.

[0072] An example of the operation of the device 100 described above is given below, linked to [Fig.6] which represents a flowchart of the steps implemented during this operation.

[0073] Reference numeral 200 designates the standby state of device 100. In this state, the AFE 130 is switched off and the integrated circuit 132 operates in a low-power mode. In particular, when device 100 is in standby mode, the amplifier 116 is not powered and some of the functions of the microcontroller 124 are in standby mode. In this standby state, however, device 100 remains on the lookout for a request to modify the threshold value vth (step 202) and also compares the value of the measurement signal ch_in with the threshold value vth (step 204).

[0074] When a request to modify the threshold value vth is received, the microcontroller 124 is woken up (step 206), the threshold value vth is updated with the new value received (step 208) and the microcontroller 124 returns to low power mode (step 210), the device 100 returning to the standby state (return to step 200).

[0075] When the value of the measurement signal ch_in (or the value of the voltage_out signal in the presence of the biasing circuit 106) becomes greater than the threshold value vth, the microcontroller 124 and the AFE 130 are woken up (step 212). This wake-up of the AFE 130 notably involves powering the amplifier 116. The values ​​measured by the sensor 102 are processed by the processing circuit 114 (step 214) until the value of the measurement signal ch_in (or the voltage_out signal in the presence of the biasing circuit 106) becomes less than the threshold value vth (comparison of the measurement with the threshold value vth performed in step 216). At this point, data acquisition is stopped (step 218). The AFE 130 is then switched off (step 220). A KPI (key performance indicator) is then calculated (step 222) and then transmitted out of device 100, for example wirelessly in the example described (step 224).This KPI can correspond, for example, to a peak-to-peak value, an RMS value, dominant frequency values, energy in a particular frequency band, or a power spectral density. The microcontroller 124 returns to low-power mode (step 226), and the device 100 returns to standby with the shutdown of the AFE 130 (return to step 200).

[0076] Figure 7 shows examples of signals obtained in device 100 during of a deformation measurement by sensor 102.

[0077] Reference 230 designates the measurement signal ch_in delivered by the sensor 102 when it is subjected to a deformation whose value increases.

[0078] Reference numeral 232 designates the threshold value vth and reference numeral 234 designates the voltage_out signal obtained at the output of the biasing circuit 106. At time tb, the value of the voltage_out signal becomes greater than the threshold value vth. The shut_dwn signal, designated by reference numeral 236, then changes from a high value to a low value, causing the switch 126 to become conducting in order to power the amplifier 116. Reference numeral 238 designates the charge_out signal obtained at the output of the anti-aliasing filter 118, which corresponds to the amplified and filtered measurement signal ch_in.

[0079] As can be seen in [Fig. 7], the time during which the device 100 remains in standby mode while the sensor 100 begins to undergo deformation—that is, the time during which the deformation is not measured and which corresponds to the time during which the device 100 transitions from standby to wake mode—is very short, for example, on the order of 20 ps in the case of deformation corresponding to a vibration with a frequency equal to or less than 48 kHz. The higher the cutoff frequency of the anti-aliasing filter 118, the shorter the time required to stabilize the device 100, for example, on the order of 4 ps for deformation corresponding to a cutoff frequency of 200 kHz.

[0080] For example, when the device 100 is in standby mode, the electrical current consumed by the AFE 130 can be on the order of 100 nA (corresponding to the leakage current of the MOS transistor forming the switch 126) to which is added approximately 120 nA consumed by the biasing circuit 106. In the awake state, the electrical current consumed by the AFE 130 can be on the order of 3 mA (corresponding to the consumption of the amplifier 116) to which is added approximately 102 pA consumed by the biasing circuit 106.

[0081] As previously stated, device 100 advantageously corresponds to a LoT beacon. Device 100 may include a battery for electrically powering the various elements and circuits of device 100 described above.

[0082] Alternatively, other circuits or elements of the device 100 may be put into standby mode or not be electrically powered when the device 100 is in standby mode.

[0083] The device 100 has the particular advantage of maximizing the lifespan of its battery, thanks in particular to the optimization of the management of the transitions between the wake-up and standby phases of the device 100 obtained thanks to the wake-up circuit 104 of the device 100 and the properties of the sensor 102.

[0084] In the particular embodiment described above, the device 100 has the advantage of using a measured physical quantity, here the deformation, to wake up the device 100 with a precise and programmable detection threshold, this This is possible thanks to the high-quality piezoelectric strain sensor 102. The device 100 can have only one sensor 102 to serve as the source for waking the device 100 and providing measurement data, thanks to the device 100's ability to switch very quickly from a standby to an active or awake state.

[0085] The device 100 can have, in standby, an electrical current consumption of less than 250 nA.

[0086] The device 100 makes it possible to ensure continuous, uninterrupted monitoring of the element on which the device 100 is mounted.

[0087] The device 100 is well suited to detect different types of vibration, from small rapidly changing deformations to large slow deformations.

[0088] Device 100 makes it possible to avoid latency due to decorrelation between a measured acceleration and a calculated deformation, because the sensor used for the wake-up directly measures the deformation undergone by the latter.

[0089] Thanks to the thin portion of piezoelectric material used, the sensor 102 of the device 100 exhibits a uniform frequency response, good sensitivity, and good measurement accuracy. Furthermore, the portion of piezoelectric material in the sensor 102 is sufficiently thin that the sensor 102 is flexible and can conform to the surface and contours of the element to which it is attached.

[0090] The device 100 can offer the possibility of modifying on the fly the wake-up threshold value of the device 100, which makes it possible, for example, not to wake up the device 100 when a known or expected transient event occurs for which the threshold value is adapted.

[0091] The piezoelectric material sensor 102 also has the advantage of having a lower electrical consumption than a resistive gauge.

[0092] Among the many possible applications of the device 100, it is particularly well suited for monitoring and measuring the fatigue of a penstock. The device 100 is also well suited for detecting when someone touches a computer server card, the sensor 102 being sensitive enough to detect the deformations caused by this contact.

[0093] Various embodiments and variations have been described. A person skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will become apparent to a person skilled in the art.

[0094] Finally, the practical implementation of the embodiments and variants described is within the reach of a person skilled in the art, based on the functional indications given above.

Claims

Demands

1. Electronic device (100) configured to operate at least in a standby or awake state, comprising at least: - a strain sensor (102) comprising at least a portion of piezoelectric material (103) whose thickness is less than 50 pm; - a wake-up circuit (104) comprising at least a comparator (110) configured to compare a value obtained from a measurement signal of the strain sensor (102) with a wake-up threshold value and output a wake-up signal of the electronic device (100) when the value obtained from the measurement signal is greater than the wake-up threshold value.

2. Electronic device (100) according to claim 1, wherein the portion of piezoelectric material (103) comprises a piezoceramic material.

3. Electronic device (100) according to any one of the preceding claims, corresponding to a deformation measurement device, and further comprising a measurement acquisition circuit (112) configured to receive as input and process the measurement signal from the deformation sensor (102), or a signal from the measurement signal from the deformation sensor (102), when the electronic device (100) is awake.

4. An electronic device (100) according to claim 3, wherein the measurement acquisition circuit (112) comprises at least: - a processing circuit (114) for the measurement signal from the strain sensor (102) or the signal derived from the measurement signal from the strain sensor (102); - a wake-up control circuit (122) configured to receive as input the wake-up signal and the measurement signal from the strain sensor (102), or to receive as input the wake-up signal and the signal derived from the measurement signal from the strain sensor (102), and to control, upon receipt of the wake-up signal, the sending of the measurement signal from the strain sensor (102) or the signal derived from the measurement signal from the strain sensor (102) to the input of the processing circuit (114) and the power supply of the processing circuit (114).

5. Electronic device (100) according to claim 4, wherein the wake-up control circuit (122) includes at least one microcontroller (124) configured to operate in a low-power mode when the electronic device (100) is in standby.

6. Electronic device (100) according to claim 5, wherein the wake-up control circuit (122) comprises at least one transmission gate (128) including at least one data input configured to receive the measurement signal from the strain sensor (102) or the signal from the measurement signal from the strain sensor (102), at least one output coupled to an input of the processing circuit (114), and at least one control input coupled to an output of the microcontroller (124).

7. Electronic device (100) according to claim 5 or 6, wherein the processing circuit (114) comprises at least one amplifier (116), and at least one switch (126) configured to control the power supply of the amplifier (116) according to a control signal intended to be emitted by the microcontroller (124) and such that the amplifier (116) is not powered when the electronic device (100) is in standby.

8. Electronic device (100) according to any one of claims 4 to 7, wherein the processing circuit (114) further comprises at least one analog-to-digital converter (120) and / or at least one anti-aliasing filter (118).

9. Electronic device (100) according to any one of claims 4 to 8, further comprising at least one wireless communication circuit configured to transmit over a wireless network data obtained from an output signal of the processing circuit (114).

10. Electronic device (100) according to claim 9, further comprising a wake-up threshold circuit (108) which is programmable and configured to apply the wake-up threshold value to the input of the comparator (110), and in which the wake-up threshold value is defined as a function of a value received by the wireless communication circuit.

11. Electronic device (100) according to claims 5 and 10, configured to switch the microcontroller (124) from low power mode to active mode upon receiving a new wake-up threshold value through the wireless communication circuit, then to update the wake-up threshold circuit (108) with the new threshold value received, and then to switch the microcontroller (124) from active mode to low power mode.

12. An electronic device (100) according to claim 7 and according to any one of claims 9 to 11, configured to turn on the switch (126) and to switch the microcontroller (124) from a low-power mode to an active mode when the value of the measurement signal from the strain sensor (102) or the signal from the measurement signal from the strain sensor (102) becomes greater than the wake-up threshold value, then to begin acquiring the measurement signal from the strain sensor (102) or the signal from the measurement signal from the strain sensor (102), then to stop the acquisition when the value of the measurement signal from the strain sensor (102) or the signal from the measurement signal from the strain sensor (102) becomes less than the wake-up threshold value, then to calculate and transmit data obtained from the acquisition performed,then to switch the microcontroller (124) from active mode to low-power mode and to put the switch (126) in the blocked state.

13. Electronic device (100) according to any one of the preceding claims, wherein the wake-up circuit (104) further comprises a biasing circuit (106) configured to receive as input the measurement signal from the strain sensor (102) and to bias the measurement signal from the strain sensor (102) and deliver on an input of the comparator (110) an output signal representative of the absolute value of the measurement signal from the strain sensor (102).

14. Electronic device (100) according to any one of the preceding claims, further comprising a power supply battery.

15. Vibration monitoring system, comprising at least one electronic device (100) according to any one of the preceding claims and computer equipment to which said at least an electronic device (100) is connected through a computer network.

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