OpenESC-20x20
Open-source 4-in-1 BLDC ESC with a 20 x 20 mm mounting pattern, part of the incutec OpenDrone line. Four independent AT32F421G8U7 motor controllers, each with an NSG2065Q gate driver and six MOSFETs, run AM32 firmware and take DShot over the standard 8-pin connector. 6S input, 6-layer PCB, designed in KiCad 10 for JLCPCB assembly. Full design detail: hardware/docs/DESIGN.md.
Status
Hardware validated, Rev2-20x20, 2026-08-05.
Latest production export set is Rev2-20x20 (2026-06-05), generated with the KiCad Fabrication Toolkit for JLCPCB assembly.
Certification
OpenESC-20x20 is certified open source hardware by the Open Source Hardware Association, OSHWA UID BE000028.
Build video: How Drone ESCs Work (so I built my own)
Links
- Product page: opendrone.be/products/openesc
- Video channel: JustFPV on YouTube
Specifications
The full specification table (channels, input, signal protocol, firmware, PCB stackup) and part-level detail (MCU, gate driver, power stage, current sense, protection) are in hardware/docs/DESIGN.md.
Repository layout
| Path | Contents |
|---|---|
hardware/ |
KiCad 10 project: schematics, PCB, project-local libraries |
hardware/docs/ |
Design documentation (DESIGN.md) |
hardware/production/ |
Fabrication exports (generated, gitignored) |
hardware/flash_openesc20.sh |
Production flash script, see Manufacturing |
hardware/tools/ |
Analysis scripts (esc_thermal.py power loss and thermal model) |
20x20-ESC-QC/ |
Press-contact QC fixture, separate KiCad 10 project |
libs/KiCad-Library |
Shared Incutec symbol/footprint/3D library (git submodule) |
images/ |
Board renders and certification marks |
licensing/ |
Third-party asset notices, trademark policy |
Design entry points
- Top schematic:
hardware/4in1-mini.kicad_sch(power, current sense, connector) - Channel schematic:
hardware/ESC.kicad_sch, instantiated 4 times - Board layout:
hardware/4in1-mini.kicad_pcb, 6 copper layers - QC fixture:
20x20-ESC-QC/20x20-ESC-QC.kicad_pro
Symbols and footprints are embedded in the design files, so the schematics and board open without any external library. The project-local libraries are hardware/components.kicad_sym and hardware/4in1ESC.pretty/; the project lib tables also reference the shared Incutec library from the libs/KiCad-Library submodule, used for new parts. The QC fixture carries its own project-local libraries (ESC-QC.kicad_sym, ESC-QC.pretty/) and, for its contact pads, KiCad's stock TestPoint library, see 20x20-ESC-QC/README.md.
Build and export
git clone --recursive https://github.com/incutec-hw/OpenESC-20x20.git
Open hardware/4in1-mini.kicad_pro in KiCad 10. Production exports (gerbers, BOM, CPL) are generated with the KiCad Fabrication Toolkit plugin. Headless checks and exports use kicad-cli:
kicad-cli sch erc --exit-code-violations hardware/4in1-mini.kicad_sch
kicad-cli pcb drc --exit-code-violations hardware/4in1-mini.kicad_pcb
kicad-cli pcb export gerbers -o out/ hardware/4in1-mini.kicad_pcb
Manufacturing
Fabricated and assembled at JLCPCB: 6-layer, 1.69 mm board, LCSC parts. Per-revision BOM, CPL, and gerber sets are generated into hardware/production/ (gitignored) with the Fabrication Toolkit, using the tracked hardware/fabrication-toolkit-options.json. Assembled boards are flashed with hardware/flash_openesc20.sh (AM32 bootloader via ST-LINK).
Contributing
See CONTRIBUTING.md.
License
Hardware licensed under CERN-OHL-S-2.0, covering the design files, the project-local symbols and footprints, and the manufacturing data in this repository. See LICENSE, licensing/THIRD_PARTY.md, and licensing/TRADEMARKS.md. One bundled 3D model asset carries an upstream GPL notice, see the third-party notes.
LICENSE stays at the repository root so GitHub detects the primary project license.