Motion detection using a shock sensor in a remote tire pressure monitoring system

• US 7,362,218 B2
• Filed: 01/20/2004
• Issued: 04/22/2008
• Est. Priority Date: 01/20/2004
• Status: Active Grant

• Current Assignee: Sensata Technologies Incorporated (Sensata Technologies Holding Plc)
• Original Assignee: Schrader-Bridgeport International Incorporated (Pacific Industrial Company Limited)
• Inventors: McCall, Alan Kenneth, Stewart, William David
• Primary Examiner(s): Lee; Benjamin C.
• Assistant Examiner(s): PHAM, LAM P
• Application Number:
  US10/761,772
• Publication Number:
  US 20050156722A1
• Time in Patent Office: 1,554 Days
• Field of Search: 340442-448, 731461-1465, 731/468, 152/152.1
• US Class Current: 340/447
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver

Abstract

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.

Claims

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.