⚙️ DIY Flipper Zero

WARNING: I do not take responsibility if you damage your board or property. This guide is for educational purposes only — proceed at your own risk.

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📚 Table of contents

• ⚙️ DIY Flipper Zero
  • 📚 Table of contents
  • Summary
  • What works / Limitations
  • Key pins & wiring (quick reference)
  • MCP23017 — Buttons & RGB wiring guide
    • Button-to-MCP mapping (from firmware)
  • How to flash (OTP + firmware)
  • Notes & tips
  • Credits
  • Currently busy with a high-priority production release: baby_v1.0 🧑‍🍼
  • ☕ Support this project

Summary

This target implements a Flipper-style board based on the STM32WB55CGU6 and integrates the following external hardware:

• 

• Figure 1 — Prototyp

• ✅ I2C OLED display (SH1106 / SSD1306)

• ✅ INA219 (battery/current monitor)

• ✅ MCP23017 (I/O expander for buttons, RGB, vibro)

• ✅ microSD (SPI)

• ✅ CC1101 sub-GHz module

• ✅ Buttons (handled via MCP23017)

• ✅ RGB status LED (via MCP23017)

• ✅ Speaker / buzzer (TIM16)

• ✅ IR RX/TX

• ✅ Vibration motor (via MCP23017)

• ✅ Li-ion battery + optional 3.7→5V boost

What works / Limitations

• ✅ Most official Flipper features are implemented.

• ✅ I2C: INA219, MCP23017, OLED (I2C preferred to free SPI).

• ✅ IR (RX/TX) and speaker/vibro outputs work.

• ✅ MCP23017 handles buttons, RGB LED and vibro (pins B1/B2/B3, B0 respectively).

• ✅ SD card over SPI is supported (CS on PA10).

• ⚠️ NFC won't work.

Key pins & wiring (quick reference)

Important: these macros are defined in furi_hal_resources.* and are used across the HAL code.

Component	Bus / Interface	MCU pin (macro)	Notes
I2C (power/default, I2C1)	I2C1	SCL: PA9 (I2C_1_SCL_GPIO_Port/I2C_1_SCL_Pin) SDA: PB9 (I2C_1_SDA_GPIO_Port/I2C_1_SDA_Pin)	Used by INA219, default MCP23017 and oled screen
I2C (external, I2C3)	I2C3	SCL: PA7 (I2C_3_SCL_GPIO_Port/I2C_3_SCL_Pin) SDA: PB4 (I2C_3_SDA_GPIO_Port/I2C_3_SDA_Pin)	Useful for external I2C
SPI1 (shared)	SPI1	MISO: PA6 (SPI_MISO_Pin), MOSI: PB5 (SPI_MOSI_Pin), SCK: PB3 (SPI_SCK_Pin)	CC1101 and SD share this bus
CC1101	SPI + IRQ	CS: PA15 (CC1101_CS_Pin), G0: PA1 (CC1101_G0_Pin)	Module IRQ on G0
SD card	SPI	CS: PA10 (SD_CS_Pin)	SD on SPI; slow/fast presets available
MCP23017	I2C	INT: PB0 (MCP_INT_Pin)	Default I2C address 0x20; RGB pins B1/B2/B3 (MCP pins 9/10/11); vibro on B0 (pin 8)
IR	GPIO / ALT	RX: PA0 (IR_RX_Pin), TX: PA8 (IR_TX_Pin)	TX is IR LED drive — use proper resistor/transistor
Speaker	PWM	PB8 (SPEAKER_Pin) — TIM16	Use transistor/amplifier if needed
iButton	1-Wire	PA3 (iBTN_Pin)
NFC CS	SPI	PE4 (NFC_CS_Pin)	Verify wiring & driver integration
UART	USART1	TX: PB6, RX: PB7	Debug / serial
USB	USB	DM/DP: PA11 / PA12	USB lines handled by HAL init code

See the canonical pin macros in targets/f7/furi_hal/furi_hal_resources.h.

MCP23017 — Buttons & RGB wiring guide

The MCP23017 I/O expander is used for button inputs, the RGB status LED and the vibration motor.

• Default I2C address: 0x20 (7-bit). The driver probes on the "power" I2C bus (I2C1) by default.
• The driver enables internal pull-ups on input pins (GPPUA/GPPUB) and configures interrupt-on-change. Wire buttons in the active-low configuration (button -> MCP pin -> GND).

Known pin assignments (MCP23017 pin indices used by the HAL):

• Port B (pins 8..15):

  • B0 (index 8) — Vibration motor control (use a transistor/MOSFET; do NOT drive motor directly from the MCP pin).
  • B1 (index 9) — RGB Red (digital on/off via MCP functions)
  • B2 (index 10) — RGB Green
  • B3 (index 11) — RGB Blue

• Port A (pins 0..7):

  • Typically used for button inputs (active-low). The specific button-to-pin mapping depends on your board wiring; common wiring connects each button between the MCP pin and GND.

Example wiring recommendations

• Buttons: connect one side of each tactile switch to an MCP23017 GPIO (Port A recommended). Connect the other side to GND. The HAL will enable internal pull-ups so the GPIO reads HIGH when idle and LOW when pressed.
• RGB LED: connect each LED cathode (or anode depending on LED common type) to the MCP23017 pin, and the LED other terminal to the appropriate supply through a current-limiting resistor. For common-anode RGB, connect the anode to 3.3V and use MCP outputs to sink (check your LED type). Keep LED current per color <20 mA; consider using transistors or MOSFETs for higher brightness.
• Vibro motor: drive the motor via an N-channel MOSFET or transistor controlled by MCP23017 B0; add a diode or snubber and a separate power supply if required.

Interrupt wiring

• Tie the MCP23017 INT pin to MCU PB0 (MCP_INT_Pin) so the MCU EXTI line notices button changes. The HAL calls furi_hal_mcp23017_attach_int() to install the handler; ensure PB0 is connected and enabled in the board wiring.

Driver notes

• The HAL configures MCP23017 IOCON with mirror interrupts and open-drain behaviour and writes GPPUA/GPPUB (pull-ups). Buttons should be wired active-low.
• Use furi_hal_mcp23017_set_i2c_bus() if you need to switch the MCP to the external I2C bus (furi_hal_i2c_handle_external).

Safety

• Do not connect motors or high-current LEDs directly to MCP23017 pins. Use proper driver stages and consider heat/EMI mitigation for motors.

Button-to-MCP mapping (from firmware)

The running firmware contains a default mapping array mcp_pin_map_default in applications/services/input/input.c. The current mapping used by the HAL is:

Logical key	Input index	MCP pin index	MCP port/pin
Up	0	0	GPA0
Down	1	4	GPA4
Right	2	1	GPA1
Left	3	5	GPA5
OK	4	2	GPA2
Back	5	3	GPA3

If your physical board uses only five buttons or a different wiring, update the applications/services/input/input.c to match your wiring.

How to flash (OTP + firmware)

Before you start

• This touches OTP (One-Time Programmable memory). Proceed with caution.
• Keep the PC powered and avoid USB disconnects.
• Install correct drivers; on Windows use Zadig to set USB Serial or WinUSB if needed.

Step 1 — Create OTP file

1. Open your OTP utility (e.g. qFlipper OTP.exe) (In the mics folder).
2. Fill fields (example): Version 12 | Firmware 7 | Body 9 | Connection 6
   • Display: mgg — Color: black/white/transparent — Region: en_ru/us_ca_au/jp/world
   • Name: up to 8 latin/number chars
3. Generate and save the file.

Step 2 — Write OTP (dangerous)

1. Hold BOOT0 and plug the board into the PC.
2. Open STM32CubeProgrammer, choose USB connection and click Connect.
3. Select the generated OTP file and set Start Address: 0x1FFF7000.
4. Click Start Programming and wait.

If the device disappears: retry drivers/ports or reinstall STM32CubeProgrammer.

Step 3 — Install firmware (qFlipper)

1. Remove microSD to avoid errors.
2. Open qFlipper with the board connected.
3. If not detected, use Zadig to install USB Serial / WinUSB.
4. Use Install from file and pick the .dfu.

Notes & tips

• Use MOSFET/transistor drivers for motors and high-current loads. Add flyback diodes.
• Do not drive vibration motors or speakers directly from I/O without a transistor.
• Verify MCP23017 address straps if you have multiple I2C devices.
• If a peripheral is not detected, try switching MCP23017 to the external I2C bus with furi_hal_mcp23017_set_i2c_bus().

Credits

Thanks to Nucleus Dark for inspiring this project.

Currently busy with a high-priority production release: baby_v1.0 🧑‍🍼

• This README was generated with the help of Copilot using a guided structure. I’ve reviewed it carefully, but you may still notice the occasional “robotic” sentence 😄
• My baby needs his father, but I’ll always do my best to support this project. If you run into any issues, please feel free to open one.
• If you find this project helpful, please consider supporting me and my growing family ❤️

☕ Support this project

If this project helps you, please consider buying me a coffee: