# mRo Pixracer


PX4 does not manufacture this (or any) autopilot. Contact the manufacturer (opens new window) for hardware support or compliance issues.

The Pixhawk® XRacer board family is optimized for small racing quads and planes. In contrast to Pixfalcon and Pixhawk it has in-built Wifi, new sensors, convenient full servo headers, CAN and supports 2M flash.


This autopilot is supported by the PX4 maintenance and test teams.

# Key Features

  • Main System-on-Chip: STM32F427VIT6 rev.3 (opens new window)
    • CPU: 180 MHz ARM Cortex® M4 with single-precision FPU
    • RAM: 256 KB SRAM (L1)
  • Standard FPV form factor: 36x36 mm with standard 30.5 mm hole pattern
  • Invensense® ICM-20608 Accel / Gyro (4 KHz) / MPU9250 Accel / Gyro / Mag (4 KHz)
  • HMC5983 magnetometer with temperature compensation
  • Measurement Specialties MS5611 barometer
  • JST GH connectors
  • microSD (logging)
  • Futaba S.BUS and S.BUS2 / Spektrum DSM2 and DSMX / Graupner SUMD / PPM input / Yuneec ST24
  • FrSky® telemetry port
  • OneShot PWM out (configurable)
  • Optional: Safety switch and buzzer

# Where to Buy

Pixracer is available from the mRobotics.io (opens new window).

Accessories include:

# Kit

The Pixracer is designed to use a separate avionics power supply. This is necessary to avoid current surges from motors or ESCs to flow back to the flight controller and disturb its delicate sensors.

  • Power module (with voltage and current sensing)
  • I2C splitter (supporting AUAV, Hobbyking and 3DR® peripherals)
  • Cable kit for all common peripherals

# Wifi (no USB required)

One of the main features of the board is its ability to use Wifi for flashing new firmware, system setup and in-flight telemetry. This frees it of the need of any desktop system.

::note ToDo Setup and telemetry are already available, firmware upgrade is already supported by the default bootloader but not yet enabled :::

# Wiring Diagrams

Grau setup pixracer top

Grau setup pixracer bottom

setup pixracer GPS

Grau b Pixracer FrSkyS.Port Connection

Grau ACSP4 2 roh

Grau ACSP5 roh

# Connectors

All connectors follow the Pixhawk connector standard (opens new window). Unless noted otherwise all connectors are JST GH.

# Pinouts

Pixracer top pinouts

Pixracer bottom pinouts

Pixracer esp

# TELEM1, TELEM2+OSD ports

Pin Signal Volt
1 (red) VCC +5V
2 (blk) TX (OUT) +3.3V
3 (blk) RX (IN) +3.3V
4 (blk) CTS (IN) +3.3V
5 (blk) RTS (OUT) +3.3V
6 (blk) GND GND

# GPS port

Pin Signal Volt
1 (red) VCC +5V
2 (blk) TX (OUT) +3.3V
3 (blk) RX (IN) +3.3V
4 (blk) I2C1 SCL +3.3V
5 (blk) I2C1 SDA +3.3V
6 (blk) GND GND

# FrSky Telemetry / SERIAL4

Pin Signal Volt
1 (red) VCC +5V
2 (blk) TX (OUT) +3.3V
3 (blk) RX (IN) +3.3V
4 (blk) GND GND

# RC Input (accepts PPM / S.BUS / Spektrum / SUMD / ST24)

Pin Signal Volt
1 (red) VCC +5V
2 (blk) RC IN +3.3V
3 (blk) RSSI IN +3.3V
4 (blk) VDD 3V3 +3.3V
5 (blk) GND GND


Pin Signal Volt
1 (red) VCC +5V
2 (blk) CAN_H +12V
3 (blk) CAN_L +12V
4 (blk) GND GND


Pin Signal Volt
1 (red) VCC +5V
2 (blk) VCC +5V
3 (blk) CURRENT +3.3V
4 (blk) VOLTAGE +3.3V
5 (blk) GND GND
6 (blk) GND GND


Pin Signal Volt
1 (red) SAFETY GND
3 (blk) VCC +3.3V
4 (blk) BUZZER- -
5 (blk) BUZZER+ -

# Debug Port

This is a Pixhawk Debug Port (opens new window) (JST SM06B connector).

Pin Signal Volt
1 (red) VCC TARGET SHIFT +3.3V
2 (blk) CONSOLE TX (OUT) +3.3V
3 (blk) CONSOLE RX (IN) +3.3V
4 (blk) SWDIO +3.3V
5 (blk) SWCLK +3.3V
6 (blk) GND GND

For information about wiring and using this port see:

# Serial Port Mapping

UART Device Port
UART1 /dev/ttyS0 WiFi (ESP8266)
USART2 /dev/ttyS1 TELEM1 (flow control)
USART3 /dev/ttyS2 TELEM2 (flow control)

# Schematics

The reference is provided as: Altium Design Files (opens new window)

The following PDF files are provided for convenience only:

# Building Firmware


Most users will not need to build this firmware! It is pre-built and automatically installed by QGroundControl when appropriate hardware is connected.

To build PX4 for this target:

make px4_fmu-v4_default

# Credits

This design was created by Nick Arsov and Phillip Kocmoud and architected by Lorenz Meier, David Sidrane and Leonard Hall.