Increasing sensitivity of a sensor using an encoded signal
A physical disturbance sensor includes a plurality of piezoresistive elements configured in a resistive bridge configuration. A signal transmitter is electrically connected to the physical disturbance sensor and configured to send an encoded signal to the piezoresistive elements of the resistive bridge configuration. A signal receiver is electrically connected to the piezoresistive elements and configured to receive a signal from the physical disturbance sensor. The received signal from the physical disturbance sensor is correlated with the sent encoded signal in determining a measure of physical disturbance.
1. A system, comprising:
a physical disturbance sensor that includes a plurality of piezoresistive elements configured in a resistive bridge configuration;
a signal transmitter electrically connected to the physical disturbance sensor and configured to send an encoded signal to the piezoresistive elements of the resistive bridge configuration; and
a signal receiver electrically connected to the piezoresistive elements and configured to receive a signal from the physical disturbance sensor, wherein the received signal from the physical disturbance sensor is correlated with the sent encoded signal in determining a measure of physical disturbance;
wherein the signal receiver is electrically connected via a same connection interface to a group of different resistive bridges, each resistive bridge of the group of different resistive bridges is connected to a different signal transmitter, and the signal receiver is configured to receive a combined signal that includes a plurality of differently encoded component signals each affected by a different corresponding one of the group of different resistive bridges.
2. The system of claim 1 , wherein the encoded signal has a frequency above 50 kHz.
3. The system of claim 2 , wherein the encoded signal has a frequency below 1 MHz.
4. The system of claim 1 , wherein the encoded signal is generated by modulating a carrier signal using a digital signal.
5. The system of claim 1 , wherein the encoded signal encodes a pseudorandom binary sequence.
6. The system of claim 1 , wherein the same signal transmitter is electrically connected via a same connection interface to a different set of resistive bridges different from the group of different resistive bridges connected to the signal receiver.
7. The system of claim 6 , wherein each resistive bridge of the set of resistive bridges connected to the same signal transmitter is connected to a different signal receiver.
8. The system of claim 1 , wherein a second signal receiver is connected to a different set of resistive bridges and the signal transmitter is connected to only one resistive bridge in the different set of resistive bridges.
9. The system of claim 1 , wherein the different signal transmitter of each of the plurality of sensors is configured to send a different encoded signal to its corresponding sensor of the plurality of sensors.
10. The system of claim 9 , wherein the different encoded signals are associated with different signal phases but encode a same pseudorandom binary sequence.
11. A method for determining a measure of physical disturbance, comprising:
sending an encoded signal to a sensor including piezoresistive elements of a resistive bridge configuration;
receiving via a signal receiver, a signal from the sensor;
correlating the received signal with the sent encoded signal; and
based at least in part on a result of the correlation, determining the measure of physical disturbance;
wherein the signal receiver is electrically connected via a same connection interface to a group of different resistive bridges, each resistive bridge of the group of different resistive bridges is connected to a different signal transmitter, and the signal receiver receives a combined signal that includes a plurality of differently encoded component signals each affected by a different corresponding one of the group of different resistive bridges.
12. The method of claim 11 , wherein receiving the signal from the sensor includes filtering the signal.
13. The method of claim 12 , wherein filtering the signal includes applying one or more of the following filters: a high pass filter, a low pass filter, or anti-alias filter.
14. The method of claim 11 , wherein correlating the received signal with the sent encoded signal includes cross-correlating a version of the received signal with a version of the sent encoded signal.
15. The method of claim 11 , wherein determining the measure of physical disturbance includes modifying the result of the correlation based on a calibration factor.
16. The method of claim 11 , wherein determining the measure of physical disturbance includes determining a maximum amplitude value of the result of the correlation.
17. The method of claim 11 , wherein the measure of physical disturbance includes a magnitude measure of one or more of the following: a strain, a force, a pressure, or a vibration.
18. The method of claim 11 , wherein each of the plurality of differently encoded component signals is associated with a different pseudorandom binary sequence.
19. The method of claim 11 , wherein the combined received signal is correlated with each of a plurality of different encoded signals corresponding to different ones of the plurality of different resistive bridges to determine a measure of physical disturbance detected by each of the plurality of different resistive bridges.
20. The method of claim 11 , wherein the received signal from the sensor is utilized in detecting a location of a touch input in addition to being used to determine the measure of physical disturbance.