Touch Sensor Assembly Using Infrared Radiations and its Applications

This paper discusses about a novel technology for introducing a touch sensor that can be applied for numerous applications, using optoelectronics. The sensor employed harnesses the attributes of an Infrared LED and an infrared photodiode. The routine touch sensor buttons can be replaced by this cost effective assembly that uses variation in amount of infrared radiations falling upon the photodiode to sense the proximity of human finger. Whenever a touch is perceived, i.e., the finger is kept at a minimum possible distance from the sensor causing maximum IR reflection, a typical amount of voltage drop is observed across the photodiode, signifying the presence of a finger. Further, the paper discusses about the variants in application of the touch sensor, as in a matrix keyboard and a household electrical appliancespsila switchboard.