Steps for Building and Testing an Obstacle-Avoidance Robot for SS 1

Class: SS 1
Term: Second Term
Week: 4
Age: 15 years
Duration: 60 minutes
Subject: Digital Technologies
Curriculum Theme: Emerging Technologies
Focal competence: Building an obstacle avoidance robot
Key competencies/values: Critical Thinking; Research and Problem Solving; Problem Solving
Skills:

• Building a two-wheel differential drive system
• Assemble the two-wheel chassis and wire motor driver connections

Previous Lesson: Obstacle-Avoidance Robot Design and Automation
Topic: Robot Design I (Obstacle-Avoidance Robot): Steps To Build A Robot
Subject Matter: Steps to build a robot

Specific Objectives

By the end of the lesson, pupils/students should be able to:

Cognitive Domain

• Identify the main steps for building a robot.
• Explain the purpose of an obstacle-avoidance robot.
• List key components required for a two-wheel differential drive system.

Affective Domain

• Appreciate the systematic approach to robot building.
• Demonstrate patience and precision during robot assembly.
• Recognise the importance of responsible use of technology.

Psychomotor Domain

• Build a two-wheel differential drive system mobile robot.
• Assemble the two-wheel chassis and wire motor driver connections.
• Integrate all components to create an obstacle-avoidance robot.

Reference Materials

The following resources were used in planning this lesson:

• 2025 New Revised Senior Secondary Education Curriculum (SSEC)
• Relevant State Unified Scheme of Work
• The HeadTeacher Scheme of work For The New Revised Senior Secondary Education Curriculum (SSEC)

Instructional Materials

The teacher will teach this lesson with the aid of:

• Robotics development starter kits (Arduino, Raspberry Pi, etc.)
• Digital multimeter
• Datasheets/Pinout sheet
• Wiring diagram
• Internet access
• Computer system
• Video on robot components and assembly

Rationale for the Lesson

This lesson provides students with practical experience in robotics, a key area in emerging technologies. Understanding the steps to build a robot fosters problem-solving skills and critical thinking. It also lays a foundational understanding for more advanced automation and control systems.

Prerequisite/Previous Knowledge

Students should have basic knowledge of digital components, simple circuits, and the concept of input/output devices.

Lesson Content/Board Summary

Robot Design I (Obstacle-Avoidance Robot): Steps To Build A Robot

Steps to Build a Robot

Building a robot involves a systematic process from conceptualisation to testing. For an obstacle-avoidance robot, these steps ensure functionality and reliability.

1. Identify Type of Robot: Determine the robot’s locomotion and structure. For this lesson, we focus on a two-wheel differential drive system.
2. Determine Purpose and Select Components: Clearly define what the robot needs to do (e.g., avoid obstacles). This purpose guides the selection of appropriate hardware and software.
3. Assemble Components: Physically connect the chosen components according to the design and wiring diagrams.
4. Test and Calibrate: Verify that all parts work as intended and fine-tune their performance for optimal operation.

Two-Wheel Differential Drive System

A two-wheel differential drive system is a common and simple mobile robot platform. It consists of two wheels independently driven by motors, typically placed on opposite sides of the robot. A third passive wheel (caster or skid) provides stability.

How it works:

1. To move straight, both motors turn at the same speed in the same direction.
2. To turn, the motors turn at different speeds or in opposite directions.
3. This system allows for precise control and manoeuvrability.

Determining Purpose and Selecting Components for an Obstacle-Avoidance Robot

The primary purpose of an obstacle-avoidance robot is to navigate an environment without colliding with objects. This purpose dictates the selection of specific components:

1. Microcontroller: The “brain” of the robot (e.g., Arduino, Raspberry Pi). It processes sensor data and controls actuators.
2. Sensors: Devices that detect obstacles (e.g., Ultrasonic sensors, Infrared sensors).
3. Actuators: Components that enable movement (e.g., DC motors).
4. Motor Driver: An electronic circuit that allows the microcontroller to control the speed and direction of the motors, as microcontrollers cannot directly supply enough current for motors.
5. Chassis: The physical frame of the robot, providing structural support for all components.
6. Wheels: For locomotion (two main driven wheels and a caster wheel).
7. Power Source: Batteries to supply electricity to all components.
8. Wiring: Connectors and cables to link all electronic components.

Assembling Components

The assembly process for a two-wheel differential drive obstacle-avoidance robot typically involves:

1. Chassis Assembly: Attaching the motors, wheels, and caster wheel to the robot’s frame.
2. Motor Driver Connection: Wiring the motor driver to the motors and the microcontroller. Ensure correct polarity and pin connections as per the datasheet.
3. Sensor Integration: Mounting the obstacle sensors (e.g., ultrasonic sensor) to the front of the robot and connecting them to the microcontroller.
4. Power Supply: Connecting the battery to the motor driver and microcontroller (often through a voltage regulator if needed).
5. Microcontroller Mounting: Securely attaching the microcontroller to the chassis.
6. Software Upload: Programming the microcontroller with code that reads sensor data and controls the motors to avoid obstacles.

Testing and Calibration

After assembly, rigorous testing and calibration are essential to ensure the robot functions correctly:

1. Power-Up Test: Verify that all components receive power and the microcontroller starts up.
2. Motor Test: Check if motors spin in the correct direction and respond to commands from the microcontroller.
3. Sensor Test: Ensure sensors accurately detect obstacles and provide reliable readings to the microcontroller.
4. Obstacle Avoidance Logic Test: Place the robot in an environment with obstacles and observe its behaviour. Adjust sensor thresholds and motor control logic as needed.
5. Calibration: Fine-tune parameters such as motor speed, sensor sensitivity, and turning angles to optimise the robot’s movement and obstacle detection.

Relevant Digital Terms

1. Microcontroller: A small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals.
2. Sensor: A device that detects and responds to some type of input from the physical environment.
3. Actuator: A component of a machine that is responsible for moving and controlling a mechanism or system.
4. Motor Driver: An integrated circuit (IC) that acts as an interface between microcontrollers and motors, providing the necessary current and voltage.
5. Algorithm: A set of rules or instructions followed in calculations or other problem-solving operations.

Responsible Practical Use of Robotics

When building and using robots, it is important to consider responsible practices:

1. Safety: Always follow safety guidelines when working with electronic components, power sources, and moving parts.
2. Ethical Considerations: Think about the potential impact of robots on society and privacy.
3. Environmental Impact: Consider the disposal of electronic waste and the energy consumption of robots.
4. Data Privacy: If robots collect data, ensure it is handled responsibly and securely.
5. Purposeful Design: Design robots to serve beneficial purposes and avoid misuse.

Teaching Methods/Instructional Techniques

Discussion, Demonstration, Guided Practice, Question and Answer, Explanation, Observation, Practical Activity

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Explaining/Engaging

Teacher’s Activity: The teacher introduces the lesson by asking students about their understanding of robots and their applications in daily life. The teacher then explains that today’s lesson will focus on the practical steps of building a simple robot.

Pupils’ Activity: Pupils share their ideas about robots and listen attentively to the teacher’s introduction.

Learning Point: Robot building overview

Step 2: Identifying Robot Type and Purpose

Time: 10 minutes

Teaching Skill: Explanation/Discussion

Teacher’s Activity: The teacher explains the concept of a two-wheel differential drive system and why it is suitable for an obstacle-avoidance robot. The teacher also discusses how the robot’s purpose (obstacle avoidance) dictates the choice of components.

Pupils’ Activity: Pupils listen, ask questions, and contribute to the discussion on robot types and purposes.

Learning Point: Robot type identification

Step 3: Component Selection

Time: 10 minutes

Teaching Skill: Demonstration/Listing

Teacher’s Activity: The teacher displays various robot components (microcontroller, sensors, motors, motor driver, chassis, etc.) and explains their functions. The teacher guides students to watch a short video demonstrating these components and their roles in a robot.

Pupils’ Activity: Pupils observe the components, watch the video, and identify the function of each component.

Learning Point: Robot component identification

Step 4: Chassis Assembly and Motor Wiring

Time: 10 minutes

Teaching Skill: Guided Practice/Demonstration

Teacher’s Activity: The teacher guides students to assemble the two-wheel chassis, attach the motors, and wire the motor driver connections according to the provided diagram. The teacher circulates to provide assistance and ensure correct wiring.

Pupils’ Activity: Pupils, in groups or individually, assemble the chassis and wire the motor driver connections under the teacher’s guidance.

Learning Point: Chassis assembly skills

Step 5: Integrating Obstacle Avoidance Components

Time: 10 minutes

Teaching Skill: Guided Practice/Supervision

Teacher’s Activity: The teacher guides students to integrate the obstacle sensors (e.g., ultrasonic sensor) and connect them to the microcontroller. The teacher explains how these sensors will enable the robot to detect and avoid obstacles, and how the microcontroller will be programmed for safe stopping.

Pupils’ Activity: Pupils integrate the sensors and microcontroller, ensuring all connections are secure for obstacle avoidance functionality.

Learning Point: Obstacle avoidance integration

Step 6: Testing, Calibration, and Responsible Use

Time: 5 minutes

Teaching Skill: Explanation/Discussion

Teacher’s Activity: The teacher explains the importance of testing and calibration for optimal robot performance. The teacher also discusses the relevant digital terms and the responsible practical use of robotics, including safety and ethical considerations.

Pupils’ Activity: Pupils listen, ask questions about testing, and participate in the discussion on responsible use of technology.

Learning Point: Testing and responsible use

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. What are the four main steps to building a robot?
2. Name two key components needed for an obstacle-avoidance robot.
3. Explain the function of a motor driver in a robot.
4. Why is testing and calibration important after assembling a robot?

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Robot building steps

Step 8: Note-Taking

Time: 10 minutes

Teaching Skill: Guided Writing

Teacher’s Activity: The teacher guides pupils/students to copy the essential Board Summary notes on the steps to build a robot and related concepts into their notebooks.

Pupils’ Activity: Pupils/students copy the notes carefully into their notebooks.

Learning Point: Essential robot notes

Step 9: Conclusion

Time: 5 minutes

Teaching Skill: Summarising

Teacher’s Activity: The teacher summarises the key steps involved in building an obstacle-avoidance robot and reiterates the importance of a systematic approach and responsible use of technology. The teacher encourages students to explore robotics further.

Pupils’ Activity: Pupils listen to the summary and prepare for the next lesson.

Learning Point: Robot building importance

Continuous Assessment/Further Study

Type: Project/Homework

Instruction: Research and present on the following:

1. Research and identify three different types of sensors that can be used for obstacle avoidance in robots, explaining how each one works.
2. Draw a simple block diagram illustrating the connection between a microcontroller, a motor driver, motors, and an obstacle sensor for a two-wheel differential drive robot.
3. Write a short paragraph on the ethical considerations of developing autonomous robots for public use.

Lesson Keywords

• Robot – A machine capable of carrying out a complex series of actions automatically, especially one programmable by computer.
• Obstacle Avoidance – The ability of a robot to detect and navigate around obstructions in its path.
• Differential Drive – A locomotion system where a robot uses two independently driven wheels to move and steer.
• Microcontroller – A small computer on a single integrated circuit, often used to control specific functions in embedded systems.
• Sensor – A device that detects and responds to physical input from the environment.
• Actuator – A component that controls a mechanism or system by converting energy into motion.
• Motor Driver – An electronic circuit that allows a microcontroller to control motors.
• Chassis – The base frame of a robot that supports its components.

Differentiation

Support: Provide simplified wiring diagrams and pre-assembled chassis components for students who struggle with fine motor skills or complex instructions. Pair struggling students with more proficient ones for guided assembly. Focus on identifying components and their basic functions.

Extension: Challenge advanced students to research different types of obstacle avoidance algorithms (e.g., wall following, potential fields) or to explore additional sensors like line followers. Encourage them to consider how to add more complex functionalities to their robot.

Suggested Lesson Videos

Search on YouTube for: “Steps to build an obstacle avoidance robot SS1 Digital Technologies” or “Arduino obstacle avoidance robot tutorial for beginners”