Laser instead of cable: hobbyist sends analog video over red beam

Transmitting analog video over a laser beam turned out to be feasible: an enthusiast known as milar111 built a LYME 101 transmitter-receiver pair that modulates composite video into red light. The project entered the recent Frikken' Laser Beams contest and, although it missed the main roundup, it is fully documented on GitHub, Instructables, and Hackaday.io, plus a YouTube video shows it in action.

The circuit is straightforward. A Raspberry Pi generates the composite signal, which drives a red laser diode through a 2N2222 transistor and passive components. On the receiving end, a BPW34 photodiode is reverse-biased for speed, and an LM318N op-amp amplifies the signal. For power, the author used two 9-volt batteries, providing a clean dual supply without extra noise.

The system connects directly to a CRT display, but getting it to work with a USB capture card required tweaks: a terminating resistor and a DC bias potentiometer were added to the transmitter. In the end, the laser link successfully delivers the picture to the screen, although the author admits it is not the most exotic way to send analog video—history includes examples with audio cassettes and unusual encodings like SECAM. Still, the project is engaging and clearly shows that visible light can replace a wire for video signals.