This mousetrap is built around a PlC12F683 and uses an infrared transmissive optical sensor that is modulated at a frequency of 38 kHz, so that it isnt affected by the ambient light. The modulation is carried out by the PlC, which generates a 38 kHz signal at port GP2, which is connected to the lR LED. The lR receiver is a type that is usually found for use with remote controls. lt reacts only