Self build Synthesizer with what I can find on the internet
The LFO is based on an Arduino Uno with a Sallen Key low pass filter and two opamps. One for level offset and span adjustment and a last stage opamp for inverting the signal.
First Pictures #1
Faceplate
The almost full bread board model
Video of the different Wave types https://youtu.be/yQFZsXjjzXU (video quality can be better)
- Green dial (a rotary encoder) is for selecting a wavetype, currently 43 types are available
- White dials are for the LFO range (a rotary encoder) and frequency (a potmeter)
- Yellow dial (a rotary encoder ) is for distortion (still to be programmed)
- Blue dials are for voltage level offset and range
The switch is for free running or synch mode.
Output jack on top is LFO output. Output jack on the bottom left is synch in. Output jack on the bottom right, fixed 0-10 volt.
- The green rotary encoder has a switch. Pushing is sets wave type to no 0, which is a triangle.
- The grey rotary encoder has a switch. Pushing is sets wave type to mid range, type 21 for now.
- The yellow rotary encoder has a switch. Pushing is sets wave type to ADSR.
In ADSR mode the yellow rotary encoder selects A - D - S or R, with the pushbuttons the levels can be increased and decreased.
- Top LED is for LFO frequency and level indication.
- Mid LED is over or under range when using the rotary encoders. (and should be placed a little more to the right for the next one)