Fpv flight controller

STM32F405 FPV Flight Controller

An open-hardware, 4-layer FPV flight controller board built around the STM32F405RGT6, designed in KiCad. Currently at hardware revision REV3. Designed to run Betaflight.

Flight video

🎥 Flight video coming soon.

3D renders

Real build photos

These photos are of the previous manufactured and tested revision of this board (see the Disclaimer section below for what changed in REV3).

Top	Bottom

Installed in the frame	Finished quad (top)	Finished quad (front)

Features

• MCU: STM32F405RGT6 (Arm Cortex-M4F, 168 MHz) — the same MCU family used by most Betaflight/iNav AIO flight controllers
• IMU: InvenSense ICM-42688-P 6-axis gyro/accelerometer (SPI)
• Barometer: Infineon DPS310 for altitude hold / GPS rescue
• OSD: MAX7456 analog on-screen display (camera in / VTX out video overlay)
• Blackbox flash: Winbond W25Q128JVP, 128 Mbit SPI NOR flash
• Power:
  • LMR51635 synchronous buck converter — VBAT down to a regulated 5V rail for the FC and video/VTX peripherals
  • AP2112K-3.3 LDO for the 3.3V digital rail, with a separately filtered +3.3VA analog rail for the IMU
• USB: USB-C receptacle with USBLC6-2SC6 ESD protection for DFU flashing / configurator access
• I/O: 5 UARTs broken out (UART1, UART2, UART3, UART5), 4 motor signal outputs (M1–M4), current sensor input, buzzer, status LED, boot/reset button, SWD programming header, and general purpose AUX/GPIO pads
• Board: 4-layer stack-up (signal / GND plane / power plane / signal)

Schematic

Full-resolution PDF: SCHEMATIC_PDF/REV3.pdf

PCB layout (copper layers)

Top copper	Bottom copper

Connector map

Reference the top-side silkscreen (visible in the top 3D render above) for exact pad locations. Grouped by function:

Repository structure

.
├── hardware/            KiCad 10 project (schematic, PCB, project settings)
│   ├── REV3.kicad_pro
│   ├── REV3.kicad_sch
│   ├── REV3.kicad_pcb
│   ├── REV3.kicad_prl
│   └── fp-lib-table
├── SCHEMATIC_PDF/
│   └── REV3.pdf         Exported schematic PDF
└── docs/
    └── images/          3D renders, copper layer renders, schematic export
        └── photos/      Real photos of the built board and quad

Opening the project

The design was created in KiCad 10.0. Open hardware/REV3.kicad_pro in KiCad to view/edit the schematic and PCB.

Firmware compatibility

Built for Betaflight. Every IC on this board is natively supported by Betaflight:

• STM32F405RGT6 — supported target MCU family
• ICM-42688-P — supported gyro/accelerometer
• MAX7456 — supported OSD chip
• W25Q128JVP — supported blackbox flash

Since this is a custom PCB (not a stock/off-the-shelf target), it needs a custom unified target in Betaflight Configurator with resource mapping matching this schematic's pin assignments: gyro on SPI1 (PA5/PA6/PA7, CS PA4), OSD on SPI2 (PB12/PB14/PB15, CS PB11), blackbox flash on SPI3 (PB3/PB4/PB5, CS PA15), motors M1–M4 on PB0/PB1/PC6/PC7, and UART1/2/3/5 as broken out on the connectors above — see the schematic for the full pin list. No target file is included in this repo yet.

Status / notes

• This repository currently contains the hardware design only (schematic + PCB). No firmware/target file is included yet.
• DRC exclusions present in the board file are inherited from the source project and should be reviewed before fabrication.

⚠️ Disclaimer

This exact revision (REV3) has not been manufactured or tested yet. It is a corrected revision of a previously manufactured and tested board, so it is very similar to a known-working unit but has not itself been built/verified. The fixes made since the last manufactured/tested version:

• The barometer (DPS310) was not connected to 3.3V — fixed.
• The boot/reset button was tied high and did not function — fixed.

The real build photos above show that previous tested revision; photos of a REV3 unit will be added once it is built.

License

Licensed under the CERN Open Hardware Licence Version 2 - Strongly Reciprocal (CERN-OHL-S v2). Anyone who manufactures or modifies this design must make their modified source available under the same licence.