L4: Embedded Systems

Key Terminology

1. Embedded System – A computer system designed for a specific task, integrated into a larger device.

2. General-Purpose Computer – A computer that can perform a wide range of tasks (e.g., PCs, laptops).

3. Microcontroller – A small integrated circuit that contains a CPU, memory, and input/output components.

4. Firmware – Permanent software programmed into an embedded system to control its functions.

5. Real-Time System – A system that responds to input immediately, often used in safety-critical devices.

6. Sensor – A device that detects and measures physical properties like temperature, motion, or light.

7. Actuator – A device controlled by an embedded system that performs an action (e.g., moving a motor).

8. Reliability – The ability of a system to perform consistently without failure.

9. Efficiency – How well a system uses resources (power, memory) to perform its tasks.

10. Integration – The combination of hardware and software into a compact system optimized for a specific function.

11. Power Consumption – The amount of electrical energy a system uses while operating.

12. Automation – The ability of a system to operate without human intervention.

13. Processing Unit – The part of an embedded system that processes instructions and data.

14. Memory – Storage for temporary or permanent data within an embedded system.

15. Input/Output (I/O) Devices – Components that allow communication between an embedded system and the outside world (e.g., buttons, displays).

Key Ideas

• Definition and Purpose

  • Embedded systems are designed for specific tasks and are built into larger devices.

  • They are different from general-purpose computers, which can perform multiple tasks.

• Examples of Embedded Systems

  • Home appliances: Washing machines, microwaves, and refrigerators.

  • Automotive systems: Anti-lock braking systems (ABS) and engine management.

  • Medical devices: Pacemakers, MRI machines, and blood pressure monitors.

  • Consumer electronics: Smartphones, cameras, and smartwatches.

• Key Components

  • Microcontroller: Contains a CPU, memory, and I/O interfaces.

  • Firmware: Pre-installed software that controls system operation.

  • Sensors: Collect data (e.g., temperature, motion).

  • Actuators: Carry out physical actions (e.g., turning a motor).

• Real-Time Systems

  • Embedded systems often work in real time, responding immediately to input.

  • Examples include airbags in cars and heart rate monitors.

• Differences from General-Purpose Computers

  • Embedded systems are task-specific, compact, and efficient.

  • General-purpose computers are more powerful and versatile but consume more resources.

Case Study: Embedded Systems in Cars

Modern cars contain dozens of embedded systems. The Anti-Lock Braking System (ABS) is one of the most critical.

1. How it Works:

   • Sensors detect wheel speed.

   • The microcontroller checks if a wheel is about to lock up.

   • The actuator adjusts brake pressure to prevent skidding.

2. Why It Matters:

   • ABS improves safety by reducing stopping distance and preventing skidding in emergencies.

Exam-Style Questions

1. (4 marks) Explain two key differences between an embedded system and a general-purpose computer.

2. (6 marks) Describe the role of a sensor, microcontroller, and actuator in an embedded system such as an automatic door.

Classroom Activities

Individual Activity: Research Task

• Find and list 5 embedded systems in your home. For each, describe its purpose, inputs, and outputs.

Pair Activity: Debate

• One student argues for general-purpose computers, and the other defends embedded systems. Discuss which is more useful in modern life.

Small Group Activity: Diagram Challenge

• In groups, draw a labeled diagram of an embedded system, showing sensor, microcontroller, actuator, and firmware. Present to the class.