Light Position Sensor
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Infrared or visible light sensors are common devices for sensing positions or presence of some component. It is desirable that the infrared or light be modulated at some frequency not likely to be encountered normally to give discrimination against ambient light or spurious interference. Normally this is done by driving the light source by some oscillator and tuning the receiving device, which requires that the receiver tuning remain on the same frequency as the oscillator. Particularly when a narrow bandwidth is used to give maximum noise rejection, this requires initial adjustment and is difficult to maintain under operational conditions.