This is a custom flight controller I designed and built for a brushed DC motor drone, powered by an ATmega328p microcontroller, nRF24l01 radio, and MPU6050 IMU. I wanted a hands-on challenge to merge my skills in PCB design, microcontrollers, and motor control—after a year of troubleshooting, it flies stable and takes wireless commands.
- Real-time stabilization using MPU6050 gyro and accelerometer data.
- Wireless control via nRF24l01 at 2.4GHz.
- Drives four brushed DC motors with custom MOSFET-based drivers.
- Lightweight 4-layer PCB with EMI shielding and efficient power distribution.
- Hardware:
- ATmega328p: Familiar, handles PWM, I2C, and SPI for motors, IMU, and radio. Runs at 3.7V (LiPo)—tested stable at 16MHz, no boost converter needed.
- MPU6050: 3-axis gyro and accelerometer for flight dynamics.
- nRF24l01: 2.4GHz radio for ground station comms.
- IRLML2502 MOSFETs: Low Rds, fast-switching drivers for four motors, with Schottky flyback diodes.
- 1S 90C LiPo: Powers it all; ditched regulators after testing.
- PCB: Started with a 2-layer board, but motor EMI kept resetting the MCU. Switched to a 4-layer design—motor drivers on bottom, sensitive components on top, ground/power planes in between for shielding, I also tried a 6-layer board which worked just as well as the 4-layer board.
- Tools: KiCAD for schematics and PCB layout, soldering iron and heat gun for assembly, Multiwii open-source software for fast firmware.
- Challenges:
- EMI from motors crashed the MCU. Tried a 5V boost converter—didn’t help. Went 3.7V direct from LiPo, still issues.
- 4-layer and 6-layer PCB rethink separated high-current and signal paths—killed the resets.
Breadboard tests nailed stable motor control; bench sims proved IMU-driven stabilization. It’s rough but works—tweaking PWM is next for smoother flight.
4-layer board
6-layer board
