Looking for some analog circuits to make i got this circuit of laser based audio transmitter on efy website. Giving it a try I decided to build one from the parts lying around. It uses a common 741 and LM386 ICs. Only schematic is available so created a layout for both transmitter and receiver. i have used signal from mobile jack instead of using microphone.
Circuit Diagram:
Transmitter
Receiver:
PCB for the above schematics built in express pcb free software
Constructed PCB using toner transfer
Receiver
here is a small video of laser audio transmission in operation
A few adjustments are required for proper alignment of the laser beam. If a milky sheet of plastic is placed in front of photo transistor, quality of sound is improved.
Layout files in pdf format can be downloaded from here: laser_layout