Stepbotslast modified 27-APR-2000 Wouter van Ooijen
(firstname.lastname@example.org) I have build a number of
stepbots: small PIC-controlled robot vehicles using stepper
motors. The basic idea is to use two steppers which are directly
connected to the front wheels, and a real wheel which can turn
freely. The two steppers take care of the propulsion and
steering. The steppers from old 5.25 disk drives are very
practical, requiring 100 mA (per coil) at 12 Volt, which can be
provided by 10 penlight NiCads. A 7805 regulator provides the 5
Volt required for the PIC 16f84 brain. A single ULN2803
interfaces the brain to the two stepper motors. I use either a
24 Volt wall wart to charge the NiCads and series resistor in
the robot that selects the appropriate charge current, or a
removeable NiCad pack. 5.25 inch diskdrives contain a number of
different stepper motor types. You can find steppers with 4, 5
and 6 wires. The 4 wire types (often found in the more recent
5.25 drives) are bipolar and can not be used with the