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Beautifully simple STM32F4 based flightcontroller. An F4 replacement for the Naze.

BlueJayF4 - rev3

Two variants (in multiple revisions). The full size, 36x36mm (30.5x30.5 mounting holes) and a 25x25mm (20x20 mounting holes) mini version.

MCU, Sensors and Features


  • MCU: STM32F405RTG6
  • IMU: ICM-20602 (SPI) rev4, ICM-20608-G (SPI) rev3 (and mini), and MPU9250 (SPI) rev1 and rev2
  • IMU Interrupt: Yes
  • BARO: Optional on full size, not available on mini.
  • VCP: Yes
  • Hardware UARTS: 3 (4 on full size with Quad motor remapping)
  • OSD: Compatible pinouts for MinimOSD on UART3 (stackable) on full size board
  • Blackbox: Yes (16mb rev3, 2mb rev1), SD card for rev2 and rev3 full size (no SD card on mini)
  • PPM/UART Shared: UART6
  • Battery Voltage Sensor: Yes, directly connected, no wiring necessary (if using pololu on full size), wiring required to vbat supply on PDB if using mini
  • Integrated Voltage Regulator: Pololu piggy back option on full size rev3 and rev4
  • Button for putting board into DFU mode


  • Current Sensor: available as ADC input, but requires shunt circuit on PDB or battery cable.
  • BlHeli passthrough: Yes
  • WS2811 Led Strip: Yes (on motor output Pin 5)
  • Transponder: No

Manufacturers and Distributors

These boards (full and mini) are available at some online RC stores, and directly from the manufacturer BlueJayRC.

Available here:

Hardware Designs (if available)

The hardware is currently closed source. It may be in the future that older revisions will be made publicly available.


BlueJayF4 rev1, 2 and 3 - including mini.

Rev3 (mini) (there is also a PDB available) bluejayf4-mini

Rev3 (Full Size) BlueJayF4 - rev3

BlueJayF4 - rev3 - bottom

Rev2 (Full Size) BlueJayF4 - rev2

Configuration Information

Wiring Diagrams

Wiring Diagram - rev4

Wiring Diagram - rev3

FrSky Smartport

Frysky smartport (or s-port) is inverted, and half duplex. You can modify your X4R or XSR by following the procedure here and here (for a cleaner modification thats easily switchable between inverted and non-inverted)

For rev3 users, the addition of a diode on UART1, and the use of the builds in BF3.1 or later allow direct connection of s-port without modifying your RX unit.

You will need to run the following in the CLI:

set sport_halfduplex=OFF

Serial Wire Debug

Serial Wire Debug output is located on the bottom of the board, and provides a pin out compatible with STM32Fx discovery boards to be used as a SWD adapter:

Wiring Diagram - rev4 SWD


Known Issues:

The rev2 requires a resistor mod to prevent the issue of crashing on power up. The rev3 does not have this issue.

Following the picture below to perform the Rev2 resistor modification: resistor-mod

The rev2 onboard regulator is limited in current capacity, and has been replaced with a pololu piggy back option for greater flexibility. soldered-pololu

Other Resources

Rcgroups Thread:

Configuring 4th UART (3.2 and later)

  • 4th hardware UART (UART4) is supported on motor outputs 1 and 2, but it is hidden until explicitly turned on by resource commands.
  • Motor outputs 1 and 2 must be remapped to avoid collision with UART4.


Below is a sequence of resource commands to configure UART4, shift motor outputs by two (Motor 1 to motor output 3, motor 2 to motor output 4 and so on) and use DEBUG pad for LED strip.

# Disable functions on motor outputs 5 and 6 so motors can be shifted by two
resource SERIAL_TX 11 NONE
resource SERIAL_RX 11 NONE
resource MOTOR 5 NONE
resource MOTOR 6 NONE

# Remap LED
resource LED_STRIP 1 B03

# Remap motors
resource MOTOR 3 B00
resource MOTOR 4 B01
resource MOTOR 1 A02
resource MOTOR 2 A03

# Configure UART4
resource SERIAL_TX 4 A00
resource SERIAL_RX 4 A01