Lesson Notes By Weeks and Term v4 - SHS 1
EMBEDDED SYSTEMS
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EMBEDDED SYSTEMS
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Subject: Engineering
Class: SHS 1
Term: 2nd Term
Week: 16
Grade code: 1.4.2.LI.2
Strand code: 4
Sub-strand code: 2
Content standard code: 1.4.2.CS.1
Indicator code: 1.4.2.LI.2
Theme: AUTOMATION AND EMBEDDED SYSTEMS
Subtheme: EMBEDDED SYSTEMS
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Welcome, future engineers! Look around you. Your phone, the prepaid electricity meter in your house, the digital microwave in the kitchen, and even the traffic lights you see on your way to school are all powered by "hidden" computers. These are not like the desktop computers in the ICT lab; they are special-purpose computers called embedded systems. They are the secret brains making our modern world smart and efficient. In the past, to make a device do something, engineers would build a fixed electronic circuit – a permanent, unchangeable arrangement of wires and components. Today, we often use embedded systems. This lesson will explore why this change happened.
This lesson is all about comparing two ways of making electronics do a specific job. Concept 1: The "Old Way" - Fixed Electronic Circuits
A Fixed Electronic Circuit (also called a hard-wired circuit) is an electronic circuit built to perform a *single, unchangeable task*. Its function is determined by the physical arrangement of its components (like resistors, capacitors, transistors, and logic gates) and the wires connecting them. Key Idea: The "intelligence" is in the hardware itself. To change the function, you must physically rebuild or rewire the circuit. Simple Analogy: Think of a simple doorbell. You press the button, a circuit is completed, and the bell rings. It can *only* do this. It cannot be updated to play a different sound or send a notification to your phone. Its function is fixed in the hardware. Ghanaian Example: An old-fashioned analogue radio tuner. You turn a knob which physically moves a capacitor to change the station. The circuitry is designed only for tuning radio frequencies. Concept 2: The "New Way" - Embedded Systems
An Embedded System is a combination of computer hardware and software designed to perform a *dedicated function* within a larger mechanical or electrical system. It is essentially a small computer (with a brain called a microcontroller or microprocessor) that is "embedded" inside another device. Key Idea: The "intelligence" is in the software (the program or code) running on the hardware. To change or add functions, you can often just update the software. Simple Analogy: Think of a smartphone. It has hardware (screen, processor, battery). But it is the software (the apps) that determines what it does. An embedded system is like a very simple, dedicated version of this. The prepaid meter in your house has a small computer inside, and the software tells it how to measure electricity, deduct units, and display the balance. Ghanaian Example: A modern ECG (Electricity Company of Ghana) prepaid meter. It has a microcontroller, memory, a display, and a keypad. The software running on it is responsible for: Accepting prepaid credit. Calculating electricity consumption. Deducting units from the balance. Showing a "low credit" warning. Disconnecting the power when the credit finishes. Concept 3: The Core Comparison - Advantages and Limitations
Let's directly compare these two approaches to understand why embedded systems are so common today.