Patent ID: 7289034
Filing Date: 2007-10-30
Classification: G01D

Abstract:
1. A sensor device comprising: a sensor unit for detecting a detection object; a processor unit for controlling supply of drive voltage to the sensor unit and detecting a change of the output voltage from the sensor unit; and a power source for supplying power to the processor unit, the sensor unit having at least a first sensor and a second sensor operating in such a way that the first sensor makes-electrical connection when the detection is in the ON state and cuts off current when the detection is in the off state, while the second sensor makes electrical connection when the detection is in the off state and cuts off current when the detection is in the on state, wherein, the detection on/off conditions of the first sensor and the second sensor are opposite and the detection operations are synchronized; wherein when the first sensor detects a detection object, the first sensor changes its output voltage level, and when the processor unit detects the change of the output voltage level of the first sensor as an interrupt signal, the drive voltage level of the first sensor is switched from the first signal level to the second signal level which is different from the first signal level and the drive voltage level of the second sensor is switched from the second signal level to the first signal level which is different from the second signal level, and moreover, when the second sensor detects a detection object, the second sensor changes its output voltage level, and when the processor unit detects the change of the output voltage level of the second sensor as an interrupt signal, the drive voltage level of the second sensor is switched from the first signal level to the second signal level which is different from the first signal level and the drive voltage level of the first sensor is switched from the second signal level to the first signal level which is different from the second signal level.