Embedded Systems

One job inside a larger device

An embedded system is a computer built into a larger product to perform a dedicated task. A washing machine controller reads the selected programme and water-level sensor, then controls valves, the heater and motor. The controller is a computer even though it has no desktop or keyboard.

A general-purpose computer can run many different applications selected by its user. A laptop might edit a document, play a game or run a spreadsheet. An embedded controller usually runs software for its product's particular task.

Worked example: automatic doors

The controller reads a proximity sensor. When someone approaches, it sends a signal to the motor actuator to open the doors. It continues checking the sensor and closes the doors when safe. Sensor → processor → actuator describes the control loop; “embedded” describes the computer's place and purpose in the larger product.

Choosing a system

Dedicated designs can be small, low-power and inexpensive because they need only the resources for their task. They can work repeatedly without a person operating them. Limited memory, difficult upgrades and failure affecting the whole product are possible disadvantages. Not every embedded system is connected to the internet.

Independent application

A supermarket replaces ordinary shelf labels with electronic labels controlled by a small computer. Explain why the controller is embedded, name an input it needs, and state one benefit and one consequence of failure.

Model comparison: the computer is part of the label system and performs a dedicated pricing/display task; it receives price updates; many labels can update without manual replacement; a fault can leave incorrect prices displayed. Your explanation should connect each point to the setting.