Flipped on purpose.
Receiver and camera pads face the front. Motor pads face the back. Two of the three dual-MOSFET packages in each motor stage sit on the front. The layout follows the wiring of an undermounted build.
UD 4IN1
A 1S AIO for racing, designed around undermounting.
See the specifications
The layout is the feature.
OSD away from the camera.
The AT7456E OSD sits low on the back of the board, away from the camera. This leaves clearance beneath the camera PCB when the canopy flexes in a crash.
USB without an onboard socket.
Four pogo contacts replace the USB socket on the flight board. Two alignment holes of different sizes guide the matching USB-C adapter into position before the contacts meet. The adapter clips on for setup and flashing.
An open camera bay.
The board outline leaves the camera bay open instead of extending PCB beneath it. That leaves more room inside the canopy for compact 65 mm race builds.
Details
- Battery
- 1S LiPo / LiHV
- PCB
- 39.32 × 25.76 mmFour layers, 0.8 mm high-Tg FR-4
- Flight controller
- STM32G473CEU6
- Firmware
- Betaflight target in development
- Gyroscope
- Bosch BMI270Dedicated low-noise supply
- ESC controllers
- 4 × EFM8BB51
- ESC firmware
- Bluejay, 48 kHz
- Power stage
- 12 × SIA517DJ dual-MOSFET packages
- Blackbox
- 16 MB W25Q128
- Video transmitter
- RTC6705 with RTC6659-series PA
- VTX firmware
- OpenVTX-based
- VTX control
- Hardware OFF and selectable output25 / 100 / 250 / MAX calibration targets
- VTX feedback
- Onboard PA detector connection
- OSD
- AT7456E, mounted on the back
- Antenna
- U.FL
- Receiver
- External serial receiver5V, GND, RX and TX
- Camera
- 5V, GND and video
- USB
- Read more
- Additional I/O
- LED strip, SWD, two status LEDs and ESC programming points
- Sensing
- Battery voltage, current and VTX PA detector
Final weight, continuous ESC rating and measured VTX output will be published after testing the first assembled boards.
What’s next
UD 4IN1 is entering prototype production. Before orders open, the first boards will be checked for power rail startup, gyro noise, ESC temperature and current, RF output across channels and temperatures, firmware recovery and durability in flight. Results from those tests will set the final specifications.
When can I buy one?
After the first assembled boards complete electrical, thermal, RF and flight testing. Pricing and availability will be published here once that testing is complete.
Will it be officially supported by Betaflight?
The schematic has been revised following feedback from Betaflight developers. Hardware testing and target submission still need to be completed before the board can be described as officially supported.
Why is the receiver external?
Durability is the main reason. On a 5IN1 AIO, board flex in a crash can crack the solder joints beneath the integrated receiver chip. If the PCB pads are damaged too, reflowing the chip will not repair them.
How does USB work?
The AIO uses a clip-on USB-C adapter. Its guide pins fit the two differently sized holes on the board to ensure proper alignment and help prevent short circuits caused by misalignment. Four spring-loaded pins press against the pads to carry power and data.
What are the final ESC and VTX ratings?
The design target is 5 A continuous per ESC. The VTX has selectable levels up to MAX, which remains a calibration target. Final ESC and VTX ratings will come from measurements on assembled boards.