4 layers100 × 68 mm
2 layers25.4 × 52 mm
Dummy
wjjmjh/dummyA minimal open-hardware ESP32-C3 dev board
- Size
- 25.4 × 52 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 18
- Nets
- 22
- Pads
- 116
- Tracks, vias
- 131, 44
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 28 Jul 2026
- Updated
- 28 Jul 2026
Overview
Dummy is an open-source printed circuit board by wjjmjh, from the wjjmjh/dummy repository on GitHub, published under the MIT licence. It is a 2-layer board of 25.4 × 52 mm with 18 parts on 22 nets, routed with 131 tracks and 44 vias.
It is built around the ESP32-C3-WROOM-02-N4 and AMS1117-3.3. Its parts include 6 capacitors, 4 resistors, 3 connectors, 2 ICs and 2 switches. It belongs with the microcontroller boards boards and the ESP32 and RISC-V boards of this library.
Main components
2
ESP32-C3-WROOM-02-N4
SMD,20x18mm-105dBm -40℃~+85℃ 2.4GHz 20.5dBm 345mA 3V~3.6V 82mA Bluetooth5.0 ESP32-C3 Chip Integrated Bluetooth function、Support USB interface On-board PCB Antenna UART、SPI、I2C、I2S、JTAG、USB SMD,20x18mm WiFi Modules ROHSEspressif SystemsWiFi Modules
AMS1117-3.3
SOT-223-40℃~+125℃ 0.003%Vout 1 1.1V@(800mA) 15V 1A 3.3V 5mA 72dB@(120Hz) Fixed Over Current Protection、Short Circuit Protection、Thermal shutdown Positive SOT-223 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSAdvanced Monolithic SystemsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
README
README.mddummy
A minimal ESP32-C3 dev board
An open-hardware ESP32-C3-WROOM-02 development board. 18 components, 25.4 × 52 mm, 2 layers, USB-C programmable. Designed by a builder, for innovators:)
Full specs, pinout, and story: dummy.cloud-mill.com
What's in this repo
| File | What it is |
|---|---|
gerbers/ | Fabrication files |
dummy.kicad_pcb | KiCad board file |
Board facts
- ESP32-C3-WROOM-02-N4 (RISC-V, 160 MHz, 4 MB flash, WiFi + BLE)
- USB-C wired directly to the chip's native USB - powers and programs the board
- AMS1117-3.3 regulator (5 V in -> 3.3 V), power from USB or the 5V pin
- RESET and BOOT buttons (hold BOOT while plugging in for download mode)
- Blue LED on GPIO8
- All 20 header pins labelled on the silkscreen
Pinout
| J2 (left) | J3 (right) |
|---|---|
| GND | IO0 |
| EN | IO1 |
| IO4 | IO2 |
| IO5 | IO3 |
| IO6 | TX (IO21) |
| IO7 | RX (IO20) |
| IO8 (LED) | IO10 |
| IO9 (BOOT) | GND |
| 3V3 | 3V3 |
| 5V | 5V |
Under the hood
License
Licensed under the MIT License.
Parts
18| Qty | Value | Footprint | References |
|---|---|---|---|
| 3 | 100n | C_0603_1608Metric | C2, C4, C5 |
| 2 | 10u | C_0805_2012Metric | C1, C3 |
| 2 | 5.1k | R_0603_1608Metric | R1, R2 |
| 1 | 10k | R_0603_1608Metric | R3 |
| 1 | 1k | R_0603_1608Metric | R4 |
| 1 | 1u | C_0603_1608Metric | C6 |
| 1 | AMS1117-3.3 | SOT-223-3_TabPin2 | U2 |
| 1 | BLUE | LED_0603_1608Metric | LED1 |
| 1 | BOOT | SW_Push_1P1T_XKB_TS-1187A | SW2 |
| 1 | ESP32-C3-WROOM-02-N4 | ESP32-C3-WROOM-02 | U1 |
| 1 | HDR-L | PinHeader_1x10_P2.54mm_Vertical | J2 |
| 1 | HDR-R | PinHeader_1x10_P2.54mm_Vertical | J3 |
| 1 | RESET | SW_Push_1P1T_XKB_TS-1187A | SW1 |
| 1 | USB-C | USB_C_Receptacle_HRO_TYPE-C-31-M-12 | J1 |
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Questions
How big is the Dummy PCB?
It measures 25.4 × 52 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Dummy use?
18 parts, built around the ESP32-C3-WROOM-02-N4 and AMS1117-3.3. 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 Dummy KiCad files?
From the wjjmjh/dummy repository on GitHub, at the commit this page was made from: the board is dummy.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the Dummy 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).