Communicate digitally over a light beam

This project slices up the human voice into forty-thousand binary segments a second, transmits it over a light-beam, then re-integrates it at the other side. That is, it applies pulse width modulation (p.w.m.) to the voice, to create a binary transmission. This is far more advantageous than similar analogue circuits, which typically achieve a range of no more than a few metres.

The circuit presented here has a range approximately five times greater than similar analogue circuits. Without the use of lenses, the prototype Photic Phone achieved a range of four metres. With a single lens at the Transmitter, it achieved a range of 15 metres. In theory, therefore, with the use of two lenses, it should achieve a range of fifty metres using a single cheap, ultrabright l.e.d.