Modern electronics allows products – consumer, industrial and scientific – to be produced with more features in smaller packages at less cost than ever before.

Not too long ago, the controller for an appliance such as a washing machine or microwave oven would have been a mechanical timer, or perhaps discrete components (switches, transistors and 4000 series logic, etc).

However, all these things take precious space and are costly to produce. Often they're difficult to update or reuse for different product models or revisions.

Today, these problems are neatly and cheaply solved with microcontrollers – single chip computers complete with IO pins, RAM, Program storage (ROM) and sometimes other useful features like ADCs, UARTS and PWM drivers.

One simply arranges for relevant inputs (switches and sensors) and outputs (motor and solenoid drivers, LEDs and displays) to be connected to the microcontroller and then write some software to manage the lot.

The space saving and cost effectiveness of these small wonders are reason enough to use them. But when you consider the flexibility they provide to adapt the control system to changes in the device or consumer demanded functionality they are indispensable.