This robot uses Mark Tildens H-Bridge design for motor drivers. The brains of the robot is a HEX inverter that until the Sharp IR detects an object the motors go forward.
This is the schematic for the SHARP IR detector. I have all the schematics, but i dont have a scanner to get it off of my notebook so i apologize for the quality. the state of the motors are either forward or reverse depending if the IR detects any object. output 2 and 4 go to the forward and reverse input of the h-bridge.
I used the wheels of an old model airplane and just screwed them to the servo hornes.
The servos are hacked...basically means i took out all the fancy stuff and just hooked two wires straight up to the positive and negative terminals of the motors. Also i had to take the mechanical stop out of the gear so that it could make a full 360 revolution.
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Here is a picture of the electrics.
H-bridge upclose and personal.