Servo Magazine (November 2010)
HoverBot: You Picked a Fine Time to Leave Me, Loose Wheel!
This time, we wrap up our HoverBot project with an explanation of the drive electronics.
******The diode is backwards in both the schematic and the diagram. The diode is reversed biased so that when the magnetic field in the relay collapses, the back emf current it creates shorts through the diode and does not flow back into the microcontroller operating the relay.******