What Is an Embedded System?

A computer hidden inside a device, built to do one job well.

An embedded system is a small computer placed inside a larger product. A washing machine, a car key fob and a thermostat each contain one. The user never sees a keyboard or desktop; the computer simply makes the product behave.

Three traits set embedded systems apart: they do a fixed task, they often must react within a strict time limit, and they run on limited memory and power. Because of this, designers think about every byte and every milliamp.

Most embedded systems follow the same loop: read inputs (buttons, sensors), decide what to do, then drive outputs (LEDs, motors, displays).