Chapter 14. Switches
Microcontrollers are great for many things where you need a little bit of computer smarts in a physical system.
One thing they’re not suited for is driving big electrical loads. The pins on the AVR are great for driving small things like our LEDs or even a speaker (decoupled with a capacitor so that it doesn’t draw too much current). But they just don’t put out enough juice to turn a motor—at least not a motor big enough to do anything meaningful!
This is a problem, because everybody needs a robot or two, and robots need motors. The AVR chips (especially the larger ones) make a great small-robot brain. Sure, you can make it flash LEDs and sing through a speaker, but ...