I was wondering if anyone has made a quadcopter from scratch and how hard it was.
By "from scratch" I mean:
Programming your own flight controller and ESCs in C;
Using say PIC microcontrollers instead of an Arduino kit;
Interfacing sensors like GPS, gyroscope, accelerometer, barometer, etc to the flight controller;
Interfacing the receiving antenna to the flight controller;
Incorporating power management such as power distribution boards / power management units.