A collection of audio projects for the CH32V003J4M6 RISC-V microcontroller, demonstrating various audio synthesis and playback techniques on an 8-pin, $0.10 microcontroller.
Brains is an open-source printed circuit board by atomic14, from the atomic14/ch32v003-audio repository on GitHub, published under the MIT licence. It is a 2-layer board of 16.3 × 11.7 mm with 15 parts on 12 nets, routed with 64 tracks and 6 vias.
It is built around the MLT-5030 and MMBT2222A. Its parts include 2 capacitors, 2 resistors, 2 connectors, 1 IC and 1 transistor. It belongs with the RISC-V boards of this library.
A collection of audio projects for the CH32V003J4M6 RISC-V microcontroller, demonstrating various audio synthesis and playback techniques on an 8-pin, $0.10 microcontroller. From simple 1-bit music to compressed audio sample playback and speech synthesis. Click on the image to watch a video and hear the results.
This repository contains several firmware projects and development tools:
The Buzzer Studio project is available here: https://buzzer-studio.atomic14.com/
A word of warning - the Buzzer Studio codebase was creating with a lot of help from AI tools. It all runs client side, there is no backend for anyone to hack. But the code may not always be easy for a human to understand.
All firmware projects build with PlatformIO. To build locally:
Simple Sound Firmware (1-bit monophonic):
cd SimpleSoundFirmware
pio runPolyphonic Sound Firmware (8-voice PWM):
cd PolyphonicSoundFirmware
pio runSample Playback (compressed audio):
cd SamplePlayback
pio runTalkie (speech synthesis):
cd Talkie
pio runFor detailed firmware information, see each project's README:
Buzzer Studio (Web App):
cd buzzer-studio
npm install
npm run devThe app allows you to:
SimpleSoundFirmware (1-bit music):
PolyphonicSoundFirmware (8-voice music):
SamplePlayback (compressed audio):
Talkie (speech synthesis):
brain-transplant/
├── SimpleSoundFirmware/ # 1-bit monophonic music playback
│ ├── src/ # Source code (main.cpp, music data)
│ ├── platformio.ini # Build configuration
│ └── README.md # Documentation
│
├── PolyphonicSoundFirmware/ # 8-voice polyphonic music
│ ├── src/ # Source code (polyphonic player)
│ ├── platformio.ini # Build configuration
│ └── README.md # Documentation
│
├── SamplePlayback/ # Compressed audio sample playback
│ ├── src/ # Source code (ADPCM decoders, PWM player)
│ │ ├── AudioStream.h # Base interface for codecs
│ │ ├── IMAAdpcmStream.* # IMA ADPCM decoder
│ │ ├── ADPCM2BitStream.* # 2-bit ADPCM decoder
│ │ ├── player.* # PWM playback engine
│ │ └── audio/ # Audio data files
│ ├── platformio.ini # Build configuration
│ └── README.md # Documentation
│
├── Talkie/ # Speech synthesis
│ ├── src/ # Source code (Talkie library port)
│ │ ├── Talkie.* # Speech synthesis engineFor Firmware Development:
For Buzzer Studio App:
For Python Scripts:
SimpleSoundFirmware (1-bit music):
PolyphonicSoundFirmware (8-voice music):
SamplePlayback (compressed audio):
Talkie (speech synthesis):
| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | LED | TestPoint:TestPoint_Pad_1.5x1.5mm | LA1, LA2, LK1, LK2 |
| 2 | 1K | Resistor_SMD:R_0603_1608Metric | R1, R4 |
| 2 | Conn_01x04_Socket | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical | J1, J2 |
| 1 | 100n | Capacitor_SMD:C_0603_1608Metric | C1 |
| 1 | 10n | Capacitor_SMD:C_0603_1608Metric | C2 |
| 1 | BAT+ | TestPoint:TestPoint_Pad_1.5x1.5mm | B+1 |
| 1 | BAT- | TestPoint:TestPoint_Pad_1.5x1.5mm | B-1 |
| 1 | CH32V003JxMx | Package_SO:JEITA_SOIC-8_3.9x4.9mm_P1.27mm | U1 |
| 1 | MLT-5030 | easyeda2kicad:BUZ-SMD_3P-L5.2-W5.2-P3.50-BR | BUZZER1 |
| 1 | MMBT2222A | Package_TO_SOT_SMD:SOT-23 | Q2 |
It measures 16.3 × 11.7 mm and has 2 copper layers, 1.6 mm thick.
15 parts, built around the MLT-5030 and MMBT2222A. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
From the atomic14/ch32v003-audio repository on GitHub, at the commit this page was made from: the board is hardware/Brains.kicad_pcb and its schematic hardware/Brains.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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