Computer Science
Grade 9
20 min
Building a Simple Robot: Using LEGOs
Students build a simple robot model using LEGOs or other building materials.
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1
Introduction & Learning Objectives
Learning Objectives
Define the core components of a robot: controller, sensors, and actuators.
Assemble a basic, functional robot chassis using LEGO parts following a guide.
Correctly connect motors and a touch sensor to a LEGO programmable brick.
Write a sequential program to make a robot move forward for a set duration and then stop.
Create a program that uses sensor input to trigger a motor action.
Explain the relationship between the physical robot (hardware) and the program that controls it (software).
Troubleshoot a common building error (e.g., incorrect port connection) in their robot.
Ever wanted to build a machine that follows your every command? 🤖 Let's bring LEGOs to life with the power of code!
In this lesson, you'll learn the fundamentals of roboti...
2
Key Concepts & Vocabulary
TermDefinitionExample
RobotA machine capable of carrying out a complex series of actions automatically, especially one programmable by a computer.A LEGO vehicle programmed to drive in a square pattern on the floor.
ControllerThe 'brain' of the robot that runs the program, processes information from sensors, and sends commands to the actuators.The LEGO Mindstorms EV3 or SPIKE Prime programmable brick.
SensorA device that detects events or changes in its environment and sends information to the controller.A LEGO Touch Sensor that detects when its button is pressed, or an Ultrasonic Sensor that measures distance.
ActuatorA component of a robot that is responsible for moving or controlling a mechanism. It converts energy into motion.A LEGO motor that turns an axle and wheel, causing...
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Core Syntax & Patterns
Sequential Execution Pattern
Program blocks execute in order, from top to bottom (or left to right).
The robot will perform the action in the first block, and only when that action is complete will it move to the next block. This is the fundamental flow for creating predictable robot behavior.
Basic Motor Control Command
Run Motor [Port] for [Duration/Rotations] at [Speed]
This is the primary command for movement. You must specify which motor to use (the port it's plugged into, e.g., Port A), how far or long it should run, and at what power level (e.g., 50% speed).
Wait-For-Sensor Pattern
Wait until [Sensor Condition is True]
Use this pattern to make the robot pause and react to its environment. The program will halt at this block until the specified sensor cond...
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Challenging
You want to program a robot to patrol an area: it moves forward, and if it bumps an object, it reverses for 1 second, turns 90 degrees right, and then continues moving forward. Which algorithm best represents this logic?
A.Loop: [Move Forward] -> [Turn Right] -> [Move Backward]
B.Loop: [Move Forward] -> [If Touch Sensor Pressed: [Move Backward] -> [Turn Right]]
C.Loop: [If Touch Sensor Pressed: [Move Forward]] -> [Else: [Move Backward]]
D.[Move Forward] -> [Wait 1 Second] -> [Turn Right]
Challenging
A student wants their robot to stop exactly 5cm away from a wall. Using only the components from the tutorial (controller, motors, touch sensor), why is this task fundamentally difficult or impossible to achieve reliably?
A.touch sensor is a binary device (pressed/not pressed) and cannot measure distance.
B.The motors are not accurate enough to stop at an exact position.
C.The LEGO controller does not have enough memory for distance calculations.
D.The chassis is too flimsy to move in a perfectly straight line.
Challenging
A robot's program is: [Start] -> [Move Steering for -2 Rotations at 50% Speed] -> [Wait 1 Second] -> [Move Steering for 2 Rotations at 50% Speed]. What is the robot's overall behavior?
A.It moves forward, waits, then moves forward again.
B.It turns in a circle for 2 rotations, waits, then turns the other way.
C.It does nothing because negative rotations are not allowed.
D.It moves backward, waits, then moves forward to its approximate starting point.
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