Planned. No design exists yet. This page is the specification: what we want built and why. If you want to design it, say so on Discord.
An all-in-one board for toothpick-class 6S FPV: flight controller, 4-in-1 ESC and ExpressLRS receiver on a single 25.5 x 25.5 mm board. One board, one connector, no stack.
The three-board stack works and OpenDrone already ships all three parts, but on a toothpick the stack is most of the weight and all of the height. Merging them removes two connectors, two sets of mounting hardware and a lot of wiring, and those connectors are where builds fail.
The parts are already proven separately, so this is an integration problem rather than a research one. That makes it a good first board for someone who has not designed for us before.
| Mounting | 25.5 x 25.5 mm |
| Input | 6S |
| Flight controller | RP2354A class, Betaflight target |
| ESC | 4 channels, AM32, distributed-MCU topology like the OpenESC boards |
| Receiver | ExpressLRS 2.4 GHz, ESP32-C3 + SX1281 |
| Assembly | JLCPCB, LCSC basic parts preferred |
The three designs this merges, all of them manufactured and flying:
- OpenFC-Lite-Mini: the RP2354A flight controller
- OpenESC-20x20: the AM32 4-in-1 power stage
- OpenRX: the ELRS receiver
Do not start from a copy of all three stitched together. That was tried and it produced a board that looked finished and was not. Start from the requirements.
These are the decisions that have to be made before any of it gets drawn, and answering them is a real contribution that needs no KiCad.
- Thermal. Four power stages next to an MCU and a radio on 25.5 mm square, with no airflow guarantee. What is the continuous current budget, and does it need copper thickness beyond 2 oz outer?
- RF isolation. A 2.4 GHz receiver sitting on top of four switching power stages. Where does the antenna go, what does the ground plane have to do, and is a shield can needed?
- Current sensing. Board level like the ESCs, or per channel?
- Video. Analog OSD, digital only, or both?
- What gets dropped. An AIO cannot carry everything the three separate boards do. Which I/O is worth the space?
Component and market work done so far is in research/. It is reference, not decisions.
Issues and pull requests are welcome on any repo. KiCad files cannot be merged, so say what you intend to change before you do, on Discord.
How everything works: CONTRIBUTING.md.
Hardware licensed under CERN-OHL-S-2.0, see LICENSE.