Remote control system for domestic lighting circuit - using modulated infrared beam transmitted between light emitting diode and photodiode to eliminate switch wiring

摘要

The system uses an IR beam provided by an autonomous battery-operated transmitter. This uses a LED providing an IR beam modulated between 25 and 200 kilohertz. The receiver associated with the lighting circuit is supplied from the mains network and uses a planar photodiode, the receiver controlling a switching triac via a bistable circuit. Pref. the photodiode is coupled to an IR filter and via an amplifier to a bandpass filter turned to the transmission range. This is followed by a further amplifier and a frequency discriminator, with a threshold output amplifier for eliminating noise.