Unlike most projects featured here this one does not really involve a specific microcontroller – since it can be used with any microcontroller having two available digital pins – both must be input output capable. This is not actually new – this paper as published July of 2003 yet we haven’t seen many projects using this as means of communication. This method is the cheapest wireless communication means that ive heard of – in terms of components just two LEDs and viola! Wireless communication!
LEDs are usually light indicators but they too can be light detectors when operated in reversed bias mode it will act as if it was a photo transistor – neat huh? Both emitter and detector in a small low cost package – to switch the LED from forward bias to reverse bias mode one must switch the digital pins from low to high thus only half duplex communication is possible when using 2 LEDs – still very cheap even compared to the IR pairs available in the market this is a steal if you can make one run on your project.