Microphone, audio playback, MIDI and sound-generation circuits with published hardware sources. These two-layer designs provide starting points for ViaGrid adaptations; signal routing and noise performance still need validation.
Published open-source PCB projects
Open source · CC BY-SA 3.0 Audio FX standalone sound-trigger player
Play stored WAV or Ogg sound effects from button inputs without a separate host controller.
Open source · CC BY-SA 3.0 MAX9814 microphone with automatic gain
An electret microphone preamp that adjusts gain as sound levels change.
Open source · CC BY-SA 3.0 MAX98357A I²S Amplifier
A digital-audio DAC and mono class-D speaker amplifier. Feed it I²S from a separate microcontroller or Raspberry Pi.
Open source · CC BY-SA 3.0 MIDI FeatherWing
Optically isolated MIDI input and output for a separate Feather host. Build a sequencer, controller or MIDI monitor.
Open source · CC BY-SA 3.0 Music Maker FeatherWing
A VS1053 audio player and MIDI synthesizer with microSD storage and stereo headphone output. Add a separate Feather host.
Open source · CC BY-SA 3.0 PCM5102 stereo line-output DAC
Convert digital I²S audio into stereo line-level output.
Open source · CC BY-SA 4.0 Si4703 FM receiver with RDS
Tune FM broadcasts and read station text through an I²C-controlled receiver with headphone output.
Open source · CC BY-SA 3.0 Si4713 stereo FM transmitter with RDS
Send line-level stereo audio and station text to an FM receiver under microcontroller control.
Open source · CC BY-SA 4.0 Sound Detector
A microphone with audio, envelope and sound-trigger outputs. Hear it, measure it, light an LED.
Open source · CC0 1.0 USB-MIDI breath controller
An ATmega16U4 and pressure sensor turn breath pressure into USB-MIDI expression, with a configurable response curve.
Other catalogued projects
| Project | License | Notes |
|---|---|---|
| StickIt! Audio I/O codec | CC BY-SA 3.0 | An AK4565 stereo ADC/DAC and LM4808 output amplifier connect analog audio input and output to an external FPGA over a PMOD or Wing interface. |
Browse these projects in the 3D PCB project directory. Open-source rows can be shallow-cloned into the git bucket. Generated board renders belong on the artifact CDN, not in git. See the hardware repository guide.