Motion detection using a shock sensor in a remote tire pressure monitoring system
View Patent ↗A tire monitor for mounting to a vehicle as part of a remote tire monitoring system includes a tire condition sensor to produce a tire condition signal, a controller coupled to the tire condition sensor to control operation of the tire monitor, and a radio circuit coupled to the controller to transmit radio signals based at least in part on the tire condition signal. A shock sensor is coupled to the controller of the tire monitor to produce a motion signal indicating motion of the tire monitor.
1. A motion detection method in a tire monitor configured for mounting on a vehicle in a remote tire monitoring system including a receiver, the method comprising:
detecting an output signal of a shock sensor;
based on the output signal, making a current motion conclusion;
testing a last saved motion conclusion;
if the current motion conclusion matches the last saved motion conclusion, transmitting data from the tire monitor for reception by the receiver;
if the current motion conclusion and the last saved motion conclusion indicate motion of the tire monitor, testing a motion decisions counter; and
if the motion decisions counter exceeds a threshold, transmitting the data from the tire monitor and entering a low power sleep mode before again detecting the output signal of the shock sensor.
2. A motion detection method in a tire monitor configured for mounting on a vehicle in a remote tire monitoring system including receiver, the method comprising:
detecting an output signal of a shock sensor;
based on the output signal, making a current motion conclusion;
testing a last saved motion conclusion;
if the current motion conclusion matches the last saved motion conclusion, transmitting data from the tire monitor for reception by the receiver; and
if the current motion conclusion does not match the last saved motion conclusion, entering a low power sleep mode before again detecting the output signal of the shock sensor.
3. A motion detection method in a tire monitor configured for mounting on a vehicle in a remote tire monitoring system including a receiver, the method comprising:
detecting an output signal of a shock sensor, wherein detecting the output signal of the shock sensor comprises:
sensing the output signal of the shock sensor;
based on the output signal, concluding the tire monitor is stationary or in motion;
upon a stationary conclusion, comparing the stationary conclusion with a previous conclusion;
if the previous conclusion matches the stationary conclusion, making the current motion conclusion that the tire monitor is stationary;
if the previous conclusion does not match the stationary conclusion, re-sensing the output signal of the shock sensor;
based on the re-sensed output signal re-concluding the tire monitor is stationary or in motion;
upon a stationary re-conclusion, making the current motion conclusion that the tire monitor is stationary; and
upon a moving re-conclusion, incrementing a motion decision counter;
based on the output signal, making a current motion conclusion;
testing a last saved motion conclusion;
if the current motion conclusion matches the last saved motion conclusion, transmitting data from the tire monitor for reception by the receiver.
4. A motion detection method in a tire monitor configured for mounting on a vehicle in a remote tire monitoring system including receiver, the method comprising:
detecting an output signal of a shock sensor, wherein detecting the output signal of the shock sensor comprises:
sensing the output signal of the shock sensor;
based on the output signal, concluding the tire monitor is stationary or in motion;
upon a moving conclusion, comparing the moving conclusion with a previous conclusion;
if the previous conclusion matches the moving conclusion, making the current motion conclusion that the tire monitor is moving;
if the previous conclusion does not match the moving conclusion, re-sensing the output signal of the shock sensor;
based on the re-sensed output signal, re-concluding the tire monitor is stationary or in motion;
upon a moving re-conclusion, clearing a motion decision counter; and
upon a stationary re-conclusion, making the current motion conclusion that the tire monitor is stationary;
based on the output signal, making a current motion conclusion;
testing a last saved motion conclusion;
if the current motion conclusion matches the last saved motion conclusion, transmitting data from the tire monitor for reception by the receiver.
5. A motion detection method in a tire monitor configured for mounting on a vehicle in a remote tire monitoring system including a receiver the method comprising:
detecting an output signal of a shock sensor, wherein detecting the output signal of the shock sensor comprises:
sampling the output signal of the shock sensor a plurality of times;
if a predetermined number of output signal samples exceed a threshold, incrementing a counter;
re-sampling the output signal of the shock sensor a second plurality of times;
if a second predetermined number of output signal samples exceed the threshold, incrementing the counter;
if the counter has been incremented twice, concluding setting a motion status flag to a moving value; and
otherwise, setting the motion status flag to a stationary value;
based on the output signal, making a current motion conclusion;
testing a last saved motion conclusion;
if the current motion conclusion matches the last saved motion conclusion, transmitting data from the tire monitor for reception by the receiver.
6. The motion detection method of claim 5 further comprising: waiting a predetermined time duration between sampling and re-sampling the output signal.
7. A motion detection method in a tire monitor configured for mounting on a vehicle in a remote tire monitoring system including a receiver, the method comprising:
detecting an output signal of a shock sensor by alternately detecting an output signal of a first shock sensor and detecting an output signal of a second shock sensor;
based on the output signal, making a current motion conclusion;
testing a last saved motion conclusion; and
if the current motion conclusion matches the last saved motion conclusion, transmitting data from the tire monitor for reception by the receiver.