Lesson Notes By Weeks and Term v4 - SHS 1
Digital and Analogue System Design
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Digital and Analogue System Design
Download the Lessonotes Mobile Ghana app for faster lesson access on Android and iPhone.
Subject: Robotics
Class: SHS 1
Term: 1st Term
Week: 17
Grade code: 1.1.3.LI.2
Strand code: 2
Sub-strand code: 1
Content standard code: 1.1.3.CS.2
Indicator code: 1.1.3.LI.2
Theme: Robot Design Methodologies
Subtheme: Digital and Analogue System Design
This page supports the lesson note with a companion video and a short classroom-ready summary.
For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.
Welcome, learners! Today, we are exploring a fundamental concept in robotics: how a robot understands the world around it. Robots use sensors, just like we use our senses of sight, hearing, and touch. However, a sensor gives the robot's brain (the microcontroller) a raw number, like '512' or '3.2 volts'. This number is meaningless on its own. Does '512' mean it's hot or cold? Near or far? This is where calibration comes in. We will learn how to translate these raw numbers into real-world, meaningful units like degrees Celsius (°C), centimetres (cm), or percentage of soil moisture. We will use a powerful tool you already know from Mathematics: linear equations (y = mx + c).
What is a Linear Sensor?
A sensor is a device that detects a change in the physical environment (like light, heat, or distance) and converts it into an electrical signal.
A linear sensor is a special type of sensor where the relationship between the physical quantity it measures and the electrical signal it outputs is a straight line. Example: If you have a linear distance sensor, moving an object 10cm further away might change the sensor's output voltage by 0.5V. Moving it another 10cm will change the voltage by another 0.5V. The change is consistent and predictable. Visual Representation: If you plot a graph with the physical quantity (e.g., Distance in cm) on the Y-axis and the raw sensor reading on the X-axis, you will get a straight line. Why is Calibration Necessary?
The 'brain' of a robot, a microcontroller like an Arduino, reads sensor data as numbers. This is often called an Analogue-to-Digital Converter (ADC) reading. For a common 10-bit ADC, this range is from 0 to 1023. A light sensor might read `120` in a dark room and `950` in bright sunlight. A temperature sensor might read `250` in a cool room and `600` in a hot room.