# Embedded Systems

- **Track:** Cambridge IGCSE™ Computer Science (0478 / 0984) (CAMBRIDGE IGCSE 0478)
- **Module:** Section 3: Hardware & Architecture
- **Estimated Duration:** 10 minutes
- **Access:** Open Theory (All-Access for Interactive IDE & Autotests)

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## Theory & Conceptual Background

## 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.

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## Interactive Exercises & Autotest Specifications

### Exercise 1: Concept Check: Dedicated purpose (Multiple choice, 30 XP)

**Instructions:**
Which description best distinguishes an embedded computer from a general-purpose computer?

**Options:**
- **A**: It performs a dedicated task within a larger product.
- **B**: It cannot contain memory.
- **C**: It must be connected to the internet.
- **D**: It never takes input.



### Exercise 2: Application: A washing machine (Fill in blank, 30 XP)

**Instructions:**
Work out each answer before submitting. Name the component detecting the water level: sensor or actuator? Name the component moving the drum: sensor or actuator? Is the controller embedded or general-purpose?


**Starter Code:**
```text
{"prompt":"Application: A washing machine","template":"1. Name the component detecting the water level: sensor or actuator? [blank_1]\n2. Name the component moving the drum: sensor or actuator? [blank_2]\n3. Is the controller embedded or general-purpose? [blank_3]","blanks":[{"id":"blank_1"},{"id":"blank_2"},{"id":"blank_3"}],"word_bank":["sensor","actuator","embedded","general-purpose","ADC","DAC"]}
```