PX4FMU Autopilot / Flight Management Unit

PX4FMU Top View

PX4FMU is a high-performance autopilot-on-module suitable for fixed wing, multi rotors, helicopters, cars, boats and any other robotic platform that can move. It is targeted towards high-end research, amateur and industry needs.

Where to Buy

Order this module from:


Key Features

PX4FMU Bottom View

  • 168 MHz / 252 MIPS Cortex-M4F
  • Hardware floating point unit
  • POSIX-compatible RTOS
  • SIMD extensions
  • 192KB SRAM / 1024 KB Flash
  • USB Bootloader (software updates, Windows, Linux, Mac OS supported)


  • 4x UART, 2x I2C, 1x SPI, 1x CAN
  • External magnetometer port (I2C1 or I2C3, compatible with this board: 3DR magnetometer breakout board)
  • microSD slot
  • PPM / RC control input (sum signal format, many compatible receivers, all channels on one connector)
  • Up to 8 GPIOs, 2 25mA high power, up to 4 PWM (servo out)
  • Battery sense (1-18V), Buzzer (up to 1.0 A, VBAT driven)
  • Reverse polarity protection on all power inputs
  • Buzzer (PWM) output
  • JTAG / SWD (ARM-Mini 10 pos / 0.05“ connector)


PX4FMU v1.7 angle

PX4FMU v1.7 top

PX4FMU v1.7 bottom

Supported Platforms / Airframes

Any multicopter, airplane, rover or boat that can be controlled with normal RC servos or Futaba S-Bus servos (S-Bus or servos: only in combination with PX4IO Airplane/Rover Servo and I/O Module, brushless motor controllers can be controlled with PX4FMU alone, up to four in a classic quadrotor setup.). More details are available on the platforms page.


PX4FMU Overview

Manual and Schematics

USB Driver

  • Windows: ZIP file, manual installation
  • Mac OS: Comes with in-built drivers, no additional driver for the micro USB port, but you need the VCP drivers (32/64 bit) on MacOS X Lion or above for the FTDI connection
  • Linux: Comes with in-built drivers, no additional driver needed

microSD Card Slot

Kingston microSD card with adapter

PX4FMU has a microSD socket and can read and write FAT (16 or 32)-formatted SD / SDHC cards (the default formatting of new SD / SDHC cards). It can log data on the SD / SDHC card or read configuration files.

List of compatible microSD / microSDHC / microSDXC cards

Matching Peripherals

PX4FMU can be used on top of these carrier boards:

A list of all peripherals (RC receivers, GPS modules, telemetry / radio modems) is available on the Peripherals page.

Stacking Spacers

Spacers to stack PX4 boards, normally delivered with carrier boards (PX4IO Airplane/Rover Servo and I/O Module / PX4IOAR - AR.Drone Shield) if bought from 3D Robotics.

  • Between-board spacers (8 mm (5/16”) height): Digi-Key Link for stacking e.g. PX4FMU and PX4IO
  • Below-board spacers (1.6 mm): Digi-Key Link For mounting PX4FMU on the platform


These jumper wires are suitable for the GPS (J4) and MULTI (J1) housings below.

PX4FMU 1.6 Pinout

For the orientation of the connectors, please refer to the full manual.

Interface to other PX4 Modules

Standalone Operation

PX4FMU can be used standalone, without any stacked PX4 carrier board, for a wide range of applications. It has 4x servo out (PWM), I2C, 1 or 2 UARTs, battery voltage sensing and a low-current 3.3V power supply output on its multi connector (details) and requires 5V power input.

Supported platforms include:

  • Quadrotor/Multirotor frames (e.g. ArduCopter (PWM, 4 rotors))
  • Small fixed wing aircraft (with a servo power harness and BEC)
  • Cars / Rovers / boats (with a servo power harness and BEC)

Stacked Operation

PX4 Stack viewed from left

The PX4 system has a stacking concept for combining the PX4FMU autopilot-on-module with a carrier board that interfaces to the platform and provides a stable 5V power supply. This concept allows customized solutions for different vehicles whilst still sharing the same autopilot module. The image on the left shows PX4FMU Autopilot / Flight Management Unit and PX4IO Airplane/Rover Servo and I/O Module stacked as complete fixed-wing/car/boat solution.

Function Mappings

Many PX4FMU pins have multiple functions. These functions can be changed at runtime, with changes saved in the onboard EEPROM. The multi_ports page explains this mechanism in detail.

Each column represents one function mapping: SRV is for PWM servo output, AR for the AR.Drone 1.0/2.0 motor interface. The 3.3V VDD pin is a 3.3V, 500 mA current-limited power output for peripherals, e.g. a radio modem. The 5.0V VDD pin is the 5.0V, reverse-polarity protected power input.

Dimensions and 3D Model

Google Sketchup can be used to view and render the highly-detailed 3D model of PX4FMU:

PX4FMU with dimensions

EDA Files (Eagle CAD)

PX4FMU is designed with Cadsoft Eagle v6.2.

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