I’m sure you have seen those inexpensive robot car chassis kits, the ones that come with two 6-volt motors. They are great fun and very useful and they even come with a couple of speed encoder disks (those little black circles full of holes). Problem is, no one tells you how to use them!
Let’s resolve that and build a robot car with speed sensors. Along the way we’ll learn how to use Interrupts, a valuable programming technique.