Pixhawk Hardware Designs
Pixhawk is an independent open-hardware project that aims to provide "the gold standard" for readily-available, hiqh-quality and low-cost autopilot hardware designs for the academic, hobby and developer communities. Pixhawk supports multiple flight stacks: PX4 ® and ArduPilot ®.
Note Designs are provided for a number of components used in unmanned vehicles, including: Autopilots (Flight Management Units - FMUs), ESCs (electronic speed controllers), optical flow sensors, etc.
What are Open Hardware Designs?
In essence, this definition allows anyone to freely study, modify, distribute, make, and sell the designs (or hardware based on the designs) under the terms of a particular open source licence.
Hardware designs delivered by the project are listed below.
FMU (Autopilot) Designs
Pixhawk FMU open designs include all information required to create an autopilot hardware product that is firmware compatible with other hardware created from the same design. Manufacturers are encouraged to take the designs and create products that are best suited to a particular market or use case (e.g. for very small vehicles, or those that operate at environmental extremes).
Note While a physical connector standard is not mandated, newer products generally follow the Pixhawk Connector Standard.
Designs are usually specified in the form of schematics that show all included components (CPU, sensors, etc.), how they are connected, and their pin mappings. They may also include a BOM (bill of materials).
Note Not all designs deliver schematics. A minimal design needs to contain enough information for manufacturers to create a compatible products; this can also be achieved using a precise pinout definition and information about connections of internal/external busses, etc.
Open Reference Hardware
The project provides open reference hardware/layouts for some open designs, in some versions. These are provided in the form of PCB layout files.
The reference hardware files are shared under the same license as the associated open design, and hence may be used in the same way(s).
The Pixhawk project has evolved the FMU design through a number of verisons.
These are named using the designation: FMUvX (e.g.: FMUv1, FMUv2, FMUv3, FMUv4, etc.). Higher FMU numbers indicate that the board is more recent, but may not indicate increased capability (versions can be almost identical - differing only in connector wiring).
The versions are listed below (with a high level overview of the main differences).
|FMUv1 & IOv1||2012||None||168 MHz M4||(Discontinued) Original Flight Management Unit and Separate I/O board.|
|FMUv2||2013||Pixhawk 1||168 MHz M4||Single board with STM32427VI processor.|
|FMUv3||2015||Pixhawk 2||168 MHz M4||Redundant sensors. Identical to FMUv2, but usable flash doubled to 2MB.|
|FMUv4||2015||Pixracer||168 MHz M4||Increased RAM. Faster CPU. More serial ports. No IO processor.|
|FMUv4X||2017||Pixhawk 3 Pro||168 MHz M4||Slightly increased RAM. More serial ports. IO processor. Redundant sensors.|
|FMUv5||2018||Pixhawk 4||200 MHz M7||New processor (F7). Much faster. More RAM. More CAN busses. Much more configurable.
> Note Minimum specification provided (pinout info, but no schematics).
|FMUv5X||2019||Pixhawk 5X||200 MHz M7||Temp-calibrated, redundant sensors.|
Note Products based on Pixhawk designs are listed here: PX4 User Guide > Pixhawk Series.
Derived FMU Products
Commercial products that are derived (under the terms of the open source license) from the Pixhawk FMU designs must provide their schematics and other information.
Relevant products are listed below:
- Sapog ESC Hardware - The directory sapog_reference_hardware contains the reference hardware design for the Sapog ESC firmware.
Pixhawk standards are developed in a weekly public developer call.
The call is shown in the Dronecode calendar as: Pixhawk Hardware Standards Weekly Call (all call details are in the entry).
Licensing and Trademarks
Pixhawk project schematics and reference designs are licensed under CC BY-SA 3.
The license allows you to use, sell, share, modify and build on the files in almost any way you like - provided that you give credit/attribution, and that you share any changes that you make under the same open source license (see the human readable version of the license for a concise summary of the rights and obligations).
Note Boards that are derived directly from Pixhawk schematic files (or reference boards) must be open sourced. They can't be commercially licensed as proprietary products.
Manufacturers can create (compatible) fully independent products by first generating fresh schematic files that have the same pin mapping/components as the FMU designs. Products that are based on independently created schematics are considered original works, and can be licensed as required.
The term Pixhawk is a trademark, and may not be used in product names without explicit permission from the trademark owner.
Typically this trademark is granted to the first board based on a particular FMU design and/or boards that use Pixhawk open reference hardware layouts.
Note A "Pixhawk" is an autopilot that has been been given permission to use the Pixhawk trademark in its name. While other boards are based on the "Pixhawk FMU Standard", the are not strictly speaking "Pixhawks".