What is a microprocessor?

Microprocessors are the "brains" behind your electronics project. Your program is loaded, stored, and executed on the microprocessor. There are many types of microprocessors available, either as a single chip or as part of a controller board. The picture shows a controller board from Wright Hobbies that comes with an Atmel Mega32, pins for input/output (sensors, motors, power, switches, displays, etc.), and a programming port.