Pixhawk is an independent open-hardware project providing readily-available, low-cost, and high-end, autopilot hardware designs to the academic, hobby and industrial communities. "Pixhawk-series" boards run PX4 on the NuttX OS.
Manufacturers have created many different boards based on the open designs, with form factors that are optimised for applications from cargo carrying though to first person view (FPV) racers.
For computationally intensive tasks (e.g. computer vision) you will need a separate companion computer (e.g. Raspberry Pi 2/3 Navio2) or a platform with an integrated companion solution (e.g. Intel® Aero Ready to Fly Drone, Qualcomm Snapdragon Flight).
The following products in the series are recommended/regularly tested with PX4:
- mRo Pixhawk
- Pixhawk 2
- Pixhawk Mini
- Pixhawk 3 Pro
This list is not exhaustive. It includes popular boards, and boards that have been used by our flight test team!
The remainder topic explains a bit more about the series, but is not required reading.
The Pixhawk project creates open hardware designs in the form of schematics, which define a set of components (CPU, sensors, etc.) and their connections/pin mappings.
Manufacturers are encouraged to take the open designs and create products that are best suited to a particular market or use case (the physical layout/form factor not part of the open specification). Boards based on the same design are binary compatible.
While a physical connector standard is not mandated, newer products generally follow the Dronecode Autopilot Connector Standard.
The project also creates reference autopilot boards based on the open designs, and shares them under the same licence.
The Pixhawk project has created a number of different open designs/schematics. Each design is named using the designation: FMUvX (e.g.: FMUv1, FMUv2, FMUv3, FMUv4, etc.).
PX4 users generally do not need to know very much about FMU versions:
- QGroundControl automatically downloads the correct firmware for a connected autopilot (based on its FMU version "under the hood").
- FMU versions are of limited use when choosing an autopilot. Versions can be almost identical (differing only in connector wiring).
- Choosing a controller is usually based on physical constraints/form factor rather than FMU version.
PX4 developers need to know the FMU version of their board, as this is required to build custom hardware.
At very high level, the main differences are:
- FMUv2: Single board with STM32427VI processor (Pixhawk 1, HKPilot32, Pixfalcon, DroPix)
- FMUv3: Addressable ram doubled to 2MB from FMUv2 (Pixhawk 2,mRo Pixhawk)
- FMUv4: Slightly increased RAM. More serial ports. No IO processor (Pixhawk Mini, Pixracer, MindPX)
- FMUv4-PRO: Slightly increased RAM. More serial ports. IO processor (Pixhawk 3 Pro)
- FMUv5: New processor (F7). Much faster. More RAM. More CAN busses. Much more configurable.