Heli’s motor take up very high current. So, a motor driver that supports less than 4 or 5 Amps was out of the question. We did not have FET’s to make a H-Bridge, so we hacked upon the radio box of the heli and connected a cable to the FET bridge already there. We also tested PWM control on these connections and it worked!
I also soldered a quick and a compact prototype board that would interface the Arduino Pro with all our sensors. I tried to install the accelerometer and the 2 gyros in the XY and YZ plane, so that, they revolve around a common center (This is not really required).