Low-power shock and vibration sensors and methods of making sensors
First Claim
1. A low-power sensor for monitoring exposure of an object to a stimulus, the sensor comprising:
- a plurality of low-friction surfaces;
a proof mass comprising a plurality of planar surfaces, wherein each low-friction surface contacts a respective planar surface of the proof mass;
at least one first piezoelectric device operable to generate a current when the proof mass imparts a force on the at least one first piezoelectric device in response to the proof mass undergoing a transient acceleration when the object is subjected to a stimulus; and
a first electronic circuit connected to the at least one first piezoelectric device, wherein the first electronic circuit is at least partially controlled in response to the current generated from the at least one first piezoelectric device due to the stimulus.
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Accused Products
Abstract
Sensors for monitoring shock or vibration of an object are provided. The sensors include a proof mass, at least piezoelectric device, and an electronic circuit connected to the piezoelectric device. The piezoelectric device generates a current when the proof mass imparts a force on the piezoelectric device in response to the proof mass being subjected to a transient acceleration when the object is subjected to a shock or vibration. The electronic circuit is at least partially controlled in response to the current generated from the piezoelectric device due to the shock or vibration. Embodiments of the sensor provide multi-axis sensing capabilities. Methods of making the sensors and flexible circuits are also provided.
30 Citations
33 Claims
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1. A low-power sensor for monitoring exposure of an object to a stimulus, the sensor comprising:
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a plurality of low-friction surfaces; a proof mass comprising a plurality of planar surfaces, wherein each low-friction surface contacts a respective planar surface of the proof mass; at least one first piezoelectric device operable to generate a current when the proof mass imparts a force on the at least one first piezoelectric device in response to the proof mass undergoing a transient acceleration when the object is subjected to a stimulus; and a first electronic circuit connected to the at least one first piezoelectric device, wherein the first electronic circuit is at least partially controlled in response to the current generated from the at least one first piezoelectric device due to the stimulus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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30. A method of monitoring exposure of an object to a stimulus, comprising:
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arranging a sensor with respect to an object, the sensor comprising; a proof mass; at least one first piezoelectric device operable to generate a current when the proof mass imparts a force on the at least one first piezoelectric device in response to the proof mass undergoing a transient acceleration when the object is subjected to a stimulus; and a first electronic circuit connected to the at least one first piezoelectric device, wherein the first electronic circuit is at least partially controlled in response to the current generated from the at least one first piezoelectric device due to the stimulus; converting a magnitude of the current to a first voltage; storing the first voltage; in real time, sensing the current and determining whether the current exceeds a threshold current corresponding to a threshold transient acceleration; when the current exceeds the threshold current, creating a second voltage from the current produced by the stimulus, wherein the second voltage triggers an interrupt; monitoring the interrupt to determine a duration of the stimulus; storing a peak value of the first voltage proportional to the current generated by the stimulus; and reading the peak value of the first voltage and recording the peak value and a time stamp in a memory. - View Dependent Claims (31)
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32. A low-power sensor for monitoring exposure of an object to a stimulus, the sensor comprising:
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a proof mass; at least one first piezoelectric device operable to generate a current when the proof mass imparts a force on the at least one first piezoelectric device in response to the proof mass undergoing a transient acceleration when the object is subjected to a stimulus; and a first electronic circuit connected to the at least one first piezoelectric device, the first electronic circuit comprising; an event driven circuit operable to (i) convert a magnitude of the current to a first voltage, (ii) in real time, sense the current to determine whether the current exceeds a threshold current corresponding to a threshold transient acceleration, and (iii) when the current exceeds the threshold current, create a second voltage proportional to the current, wherein the second voltage triggers an interrupt; a peak and hold unit operable to store a peak value of the first voltage proportional to the transient acceleration; and a microcontroller operable to (i) monitor the interrupt to determine the duration of the stimulus and (ii) read the stored peak value of the first voltage and record the peak value and a time stamp in a memory.
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33. A low-power sensor for monitoring exposure of an object to a stimulus, the sensor comprising:
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a proof mass; at least one first piezoelectric device operable to generate a current when the proof mass imparts a force on the at least one first piezoelectric device in response to the proof mass undergoing a transient acceleration when the object is subjected to a stimulus; a peak and hold capacitor operable to store a voltage corresponding to the current; a first electronic circuit connected to the at least one first piezoelectric device, wherein the first electronic circuit is operable to generate an interrupt in response to the current generated from the at least one first piezoelectric device due to the stimulus; and a microcontroller operable to read a voltage value from the peak and hold capacitor in response to the interrupt.
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Specification