I picked up a Big Trak programmable vehicle from a car boot sale a few years ago where it promptly got lost in my to be used in a cool project (aka junk) pile. The recent Dorkbot @ Newcastle project session saw me dig it out of my attic with the goal of swapping out the original controller board an replacing it with an Arduino.
To make this work I needed a motor controller circuit to drive the wheels of the Big Trak. There are a number of Arduino motor controller shields I could have used but I already had a couple of ST L6203 H-Bridge Driver chips left over from a previous project so I put together a quick dual motor controller design using these.
A pdf of the initial schmatic design is here