The Moog Light Synth V2 Features 10 Keys for Terrific Tones
Lonesoulsurfer's latest design uses a PWM oscillator routed through a light-controlled resonant low-pass filter to produce different tones.
Lonesoulurfer is no stranger when it comes to synths, as he's built a few of them over the years, including one with an integrated drum pad. His latest is the Moog Light Synth V2, which is no less impressive in its design.
"This synth is a pulse width modulated oscillator, routed through a light-controlled resonant low pass filter. The 'growling' oscillator tonality is supplied via a PWM and an awesome high-resonance low pass filter," Lonesoulsurfer writes in his project post. "The oscillator is controlled via 2 Light dependent resistors (LDR) and gives you the ability to create amazing musical expression. The 10 "keys" give you different tones and allow you to play it like a keyboard."
The synth was designed around a pair of hex inverter drones using a 40106 IC, which outfits the musical box with three oscillators in total. Users can also turn off the drone oscillators in favor of just one, for those who prefer to be minimalistic. Even implementing one potentiometer and both LDRs can produce some exciting tones, especially when combined with echo and reverb.
Lonesoulsurfer constructed the synth using a custom PCB that features the oscillators and 10 trimmer pots, which were assembled with Eagle for an efficient layout. He combined the PCB with an echo/reverb module, along with a handful of off-the-shelf parts, including potentiometers, momentary switches, and SPDT switches. He used a LiPo battery and a charging and voltage regulator module, making the synth portable.
Lonesoulsurfer has uploaded a detailed walkthrough of his Moog Light Synth V2 on his Instructables page, complete with schematics, for those who would like to recreate his build.