Building a drone from absolute scratch as a 1st year student — no Betaflight, no ready-made FC, everything coded by hand ?
Building a fully custom autonomous quadcopter from scratch — no Betaflight, no off-the-shelf FC. Looking for advice
Hey everyone! I'm a 1st/2nd year engineering student and I'm building a drone called **Raya** completely from the ground up over 6 months — firmware, transmitter, airframe, everything. No Betaflight, no pre-made flight controller. Here's what I'm working with:
The drone brain
- Arduino Nano running a custom PID algorithm (reads MPU6050 IMU, outputs PWM to 4 ESCs at ~500 Hz)
- Arduino Uno handling all the autonomy logic (optical flow, ultrasonic sensors, flight mode management)
- These two talk to each other over UART serial
Flight modes I'm building
Manual— full stick control, Nano keeps it stable
Stable mode— toggle it and Raya holds position + altitude using a PMW3901 optical flow sensor and HC-SR04 ultrasonic (no GPS)
Normal landing — manual throttle-down
Kill switch— one toggle triggers a fully autonomous safe landing sequence, cuts motors on touchdown
Custom transmitter
- ESP32 + LoRa SX1278 (433 MHz) for ~2–3 km range with zero WiFi — pure radio
- Dual analog joysticks, 0.96" OLED showing battery + flight mode, mode toggle and kill switch
- The drone also has an ESP32 as the radio receiver, which forwards everything to the Uno over UART
AirframeF450 frame with everything mounted custom — prop guards, rubber dampeners, foam-padded electronics bay, zip-tie breakpoint arms
Total budget: under ₹7,500 (~$90 USD
I'm learning all the physics and writing every line of code myself. Currently at the start of the journey and trying to understand as much as possible before I start building.
A few things I'd love input on:
- Any tips on tuning a PID from scratch without an oscilloscope?
- Best way to test the motor mixing algorithm before the frame is assembled?
- Anyone used PMW3901 for indoor position hold on a homebrew FC? How reliable is it?
Happy to share more details, schematics, or code as I progress. Thanks in advance!