2 layers223.5 × 160 mm
4 layers30.5 × 68.6 mm
Modular Synths for Everyone
- Size
- 30.5 × 68.6 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 62
- Nets
- 74
- Pads
- 276
- Tracks, vias
- 520, 71
- Pours
- 5
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 4 Oct 2024
- Updated
- 25 Oct 2026
Overview
32bit is an open-source printed circuit board by bread-modular, from the bread-modular/bread-modular repository on GitHub, published under the MIT licence. It is a 4-layer board of 30.5 × 68.6 mm with 62 parts on 74 nets, routed with 520 tracks and 71 vias.
It is built around the ESP32-S3-WROOM-1U-N16R8, K2-1808SN-A4SW-01 and GZ2012D121TF. Its parts include 25 capacitors, 22 resistors, 3 ICs, 3 switches and 1 diode. It belongs with the audio and music boards and the ESP32 boards of this library.
Main components
3
ESP32-S3-WROOM-1U-N16R8
SMD,19.2x18mm-103.5dBm -40℃~+65℃ 2.4GHz 20.5dBm 355mA 3V~3.6V 95mA Bluetooth5.0 ESP32-S3R8 UART、SDIO、SPI、I2C、GPIO、PWM、ADC、I2S、JTAG、USB SMD,19.2x18mm WiFi Modules ROHSEspressif SystemsWiFi Modules
K2-1808SN-A4SW-01
SMD,4.2x3.3mm-25℃~+85℃ 100,000 cycles 12V 2.5N 2.5mm 3.25mm 4.2mm 50mA Oval Button SPST Surface Mount,Vertical SMD,4.2x3.3mm Tactile Switches ROHSHRO ElectronicsTactile Switches
GZ2012D121TF
0805-55℃~+125℃ 1 120Ω@100MHz 150mΩ 800mA ±25% 0805 Ferrite Beads ROHSSunlordFerrite Beads
README
README.mdBread Modular
An open-source hardware modular synthesizer format designed to be minimalistic and cost-effective: USB-powered, breadboard-friendly, with analog/digital modules and MIDI alongside CV & Gate.
Find your starting point
- Build or explore: modules, specification, common parts.
- Set up KiCad libraries: workspace/library setup. Projects
use the shared
opt/fp-lib-table; initialization copies local submodules rather than cloning them. - Check/export/source parts: KiCad toolkit.
Canonical tools, JLCPCB utilities and skills live under
opt/kicad-tools/.
KiCad quick start
python3 -B opt/kicad-tools/kicad_tools.py --help
python3 -B opt/kicad-tools/kicad_tools.py doctor
python3 -B opt/kicad-tools/kicad_tools.py export --helpPython + installed KiCad CLI; no extra packages for core tools. Private checks,
Gerber/BOM/CPL export, native netlist helpers and read-only sourcing have
distinct requirements and safety boundaries.
Exports are not electrical/release/order approval; keep frozen module scripts
and production designs untouched. Historical opt/kicad-jlcpcb and
.agents/skills/{kicad-workflow,jlcpcb-assembly} resolve through
relative compatibility symlinks.
Agents: start with the KiCad workflow skill or assembly skill, then actual CLI help.
Project references
Module catalog · Modular MIDI · PCB assembly
- Standalone exporter / native part-number setup
- Sourcing, audits and passive planning
- 32bit-5v sourcing / release HOLD
- 16bit-5v sourcing HOLD evidence
Project image and full feature overview
- Modular design: Just like Eurorack.
- USB-powered: It can be portable.
- Minimal design: Cost-effective.
- Modular MIDI support: Communicate between modules; CV & Gate still supported.
- Analog and digital signal paths: It’s your choice.
- Diverse built-in modules: A wide range of pre-designed modules.
- Configurable digital modules: Voice and CV using AtTiny 1616 or ESP32.
- Fully open source: Schematics, PCB designs and code.
- Ease of customization: Create modules tailored to your needs.
- No case required: Use directly on a breadboard or a simple base module.
Parts
62| Qty | Value | Footprint | References |
|---|---|---|---|
| 9 | 0.1uf | Capacitor_SMD:C_0402_1005Metric | C1, C4, C6, C21, C22, C26, C34, C36, C39 |
| 6 | 100uf | Capacitor_SMD:C_1206_3216Metric | C7, C9, C10, C11, C12, C13 |
| 6 | 10uf | Capacitor_SMD:C_0402_1005Metric | C5, C27, C33, C35, C37, C38 |
| 5 | 1k | Resistor_SMD:R_0402_1005Metric | R1, R2, R9, R13, R17 |
| 5 | 33 | Resistor_SMD:R_0402_1005Metric | R7, R8, R14, R18, R26 |
| 4 | 100k | Resistor_SMD:R_0402_1005Metric | R10, R12, R16, R19 |
| 3 | K2-1808SN-A4SW-01 | BreadModular_MISC:K2-1808SN-A4SW-01 | SW1, SW2, SW4 |
| 2 | 1.5k | Resistor_SMD:R_0402_1005Metric | R5, R6 |
| 2 | 10uf | Capacitor_SMD:C_0603_1608Metric | C2, C8 |
| 2 | 4.7k | Resistor_SMD:R_0402_1005Metric | R24, R25 |
| 2 | 5.1k | Resistor_SMD:R_0603_1608Metric | R4, R11 |
| 2 | 50k | BreadModular_Pots:Potentiometer_RV09 | RV1, RV2 |
| 2 | Conn_01x05_Pin | BreadModular_MISC:Power_Connector | GND1, V_SUPPLY1 |
| 2 | Conn_01x05_Socket | Connector_PinSocket_2.54mm:PinSocket_1x05_P2.54mm_Vertical | INPUT1, OUTPUT1 |
| 1 | 10 | Resistor_SMD:R_0603_1608Metric | R15 |
| 1 | 10k | Resistor_SMD:R_0402_1005Metric | R3 |
| 1 | 10nf | Capacitor_SMD:C_0805_2012Metric | C20 |
| 1 | 1uf | Capacitor_SMD:C_0402_1005Metric | C3 |
| 1 | ESP32-S3-WROOM-1U-N16R8 | RF_Module:ESP32-S3-WROOM-1U | U1 |
| 1 | GZ2012D121TF | Capacitor_SMD:C_0805_2012Metric | FB1 |
| 1 | LED | LED_SMD:LED_0603_1608Metric | D1 |
| 1 | MCP6002-xSN | Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.29x3mm | U3 |
| 1 | USB_C_Receptacle_USB2.0_14P | BreadModular_TypeC:HRO-TYPE-C-31-M-12 | J5 |
| 1 | ~ | Package_DFN_QFN:QFN-28-1EP_4x4mm_P0.45mm_EP2.4x2.4mm_ThermalVias | U4 |
Questions
How big is the 32bit PCB?
It measures 30.5 × 68.6 mm and has 4 copper layers, 1.6 mm thick.
What parts does the 32bit use?
62 parts, built around the ESP32-S3-WROOM-1U-N16R8, K2-1808SN-A4SW-01 and GZ2012D121TF. 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.
Where can I download the 32bit KiCad files?
From the bread-modular/bread-modular repository on GitHub, at the commit this page was made from: the board is modules/32bit/32bit.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the 32bit design in my own project?
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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