I’m having so much fun making this I thought I would share.
I am working on a simple, cheap, easy to construct multi-effects guitar pedal based on the Raspberry Pi Pico microcontroller. All of the other parts are generic parts. So far I have implemented the following effects:
Noise gate, Delay, Room, Combine Effects, Bandpass Filter, Lowpass Filter, Highpass Filter, Allpass Filter, Tremolo, Vibrato, Wah, Autowah, Envelope, Distortion, Overdrive, Ring Modulator, Flanger, Chorus, Phaser, Backwards (play the last few samples backwards), Pitch Shift, and Octave (rectification).
Some effects can be cascaded inside the device. There are up to 16 “units” where each processing stage can process the results of the last stage. Various controls on the effects can be assigned to the four potentiometers at the bottom of the board, or two expression pedals you can plug into the side.
I also added a VGA output because I want to have a cool video display that changes with the audio. Also, perhaps implement some kind of guitarsynth or MIDI control.
Anyways this has been a lot of fun to make. I hope others will enjoy it too.
The ADC is run at 50 kHz, which is divided in half between the instrument itself and reading the analog controls. Every 40 microseconds the ADC is read, and the effects are processed in order, and then on the other half of the 40 microsecond cycle, the DAC is set.