InstrumentLIBRARY
Guitar Synth with CircuitPython SynthIO, a 3D-printed synth guitar
Image: still from Adafruit Industries' YouTube video
Electronic · Synth guitar

Guitar Synth with CircuitPython SynthIO

Adafruit's printed synth guitar: key switches, a strum bar and a polyphonic synth

Designed by Adafruit (Ruiz Brothers), published on Adafruit

No licence stated Ask before reuse Build info 5/5

Not stated on Learn guide; needs confirmation

Get the files on Adafruit ↗ Watch the video
Brain
Adafruit RP2040 Prop-Maker Feather (I2S audio)
Controls
8 NeoKey switches, a strum bar, 3 rotary encoders, accelerometer
Sound
On-board speaker or TRRS jack
Guide
Full Adafruit Learn guide: parts, wiring, assembly, code
Licence
Not stated for the 3D files; code MIT

About the Guitar Synth

A guitar-shaped synthesiser from Adafruit. Instead of strings you press NeoKey mechanical key switches, which light up in different colours, and play notes with a Guitar Hero-style strum bar made from two lever micro-switches. CircuitPython's synthio module generates the sound on an RP2040 Prop-Maker Feather. Three rotary encoders shape the sound, and the board's accelerometer lets you modulate it by tilting the guitar. Audio comes from a small built-in speaker, or you can switch to a TRRS headphone jack.

The Adafruit Learn guide is a complete project write-up. It lists every board, cable and screw, and covers wiring, the 3D-printed parts, step-by-step assembly and the code. Power comes from a 3 × AA holder, with a metal LED on/off switch. Most connections are plug-in STEMMA QT cables, though some wiring is needed. The official video shows it being played.

Licence note. The guide doesn't state a licence for the 3D files (the code is MIT), so we show a placeholder rather than Adafruit's photos. Check the guide before redistributing the files.

What you'll need

Printed parts

  • Guitar body, neck and covers (see the guide)

Bought parts

  • Adafruit RP2040 Prop-Maker Feather
  • 2 × NeoKey 1x4 QT boards with key switches and keycaps
  • 3 × I2C rotary encoder breakouts
  • 2 × lever micro-switches (strum bar)
  • NeoPixel stick, TRRS jack breakout and a 3 W 4 Ω speaker
  • Toggle switches and a metal on/off switch
  • 3 × AA battery holder and batteries
  • STEMMA QT and JST cables
  • M2, M2.5 and M3 screws and M3 nuts (listed in the guide)

Tools

  • Soldering iron
  • A computer to load CircuitPython and the code

Build overview

Follow the Adafruit Learn guide. In outline:

  1. Print the parts. Print the guitar parts from the guide.
  2. Prepare the electronics. Load CircuitPython and the code onto the Feather.
  3. Wire it up. Connect the NeoKeys, encoders, switches, speaker and battery.
  4. Assemble. Mount everything into the printed body and close it up.

Videos

Play video: Synth Guitar (loads YouTube)
Synth Guitar, Adafruit Industries (from Adafruit Industries). Plays from youtube-nocookie.com after you click.
Play video: 3D Hangouts: Synth Guitar (loads YouTube)
3D Hangouts: Synth Guitar, Adafruit Industries (from Adafruit Industries). Plays from youtube-nocookie.com after you click.

The videos don't load from YouTube until you press play. Video thumbnails are © their creators.

Photos

Adafruit doesn't state a licence for this guide's 3D files and photos, so the photos stay on Adafruit. See them on Adafruit ↗

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