The original design turns around a two tracking wheels and one smaller like the ones in supermarket chariots.
the two steppers will change speed and direction rotation to control the movement on each direction.
the third motor will control a webcam and ultrasound detector to calculate distances and avoid obstacles.Once it finds an obstacle it will turn around to search an alternative route.
Have you gotten the comm to the ultrasonic detector working yet? Also, I'm curious how you interfaced the EFIKA to the bumper-switches, I've got the same issue on my next design (see http://www.powerdeveloper.org/project/efika/697
), and am thinking right now using a slaved OOPIC with serial comm to the EFIKA...
Kevin Nickels, Assoc. Prof, Trinity University, San Antonio, TX, USA