[Mark] was looking for a cheap disco laser projector for parties, and he found one. Unfortunately for him, the advertised features were a bit lacking. The “sound activation mode” was merely an on off circuit, as opposed to it actually being controlled by the music — he set out to fix this.
Taking the unit apart revealed a very convenient design for hacking. All of the components were connected to the main PCB by connectors, meaning the laser driver board was completely separate! He replaced the PCB completely using a prototyping board, an Arduino pro mini, a microphone with a simple preamp, a rotary encoder, and a MSGEQ7 chip to analyse the levels. Oh, and a MOSFET to control the motor via PWM output. It even ended up being close to the same size as the original!
If you happen to have one of these projectors and want to fix it too, he’s posted the source code and circuit diagram on github.
After the break, check out the before and after video. It’s still a cheap disco laser projector, but at least it works as advertised now!