A human-following robot is more advanced than a basic obstacle-avoiding robot because it must estimate not only distance but also direction. A school prototype can use multiple sensors or a combination of ultrasonic and IR sensing to decide how the robot should move.
This tutorial is designed for students who want to understand the project rather than only copy a finished model. Build one part at a time, test each section, record what changes and prepare a short explanation of the science or engineering principle.
System architecture
The controller reads the sensors, estimates whether the target is in front, left or right, and then drives two motors through a motor driver. The robot should maintain a safe following distance rather than continuously moving forward.
- Arduino Uno/Nano
- distance sensor
- left/right detection sensors
- motor driver
- 2 geared motors
- robot chassis
- battery
Distance control
An ultrasonic sensor can estimate how far the person or target is from the robot. Define a near limit, desired following range and far limit so the robot does not collide.
Direction detection
For a simple school model, left and right IR sensors can help determine which side sees the target more strongly. More advanced versions may use multiple ultrasonic sensors or computer vision.
Motor logic
If the target is centred and farther than the chosen distance, move forward. If the target is too close, stop or reverse. If the left sensor sees the target more strongly, turn left, and similarly for the right.
Safety and limitations
This is a demonstration robot, not a safety-certified autonomous system. Sensors can fail on unusual surfaces, in strong sunlight or when several people are nearby.
Step-by-step build
- Assemble the chassis and test each motor direction.
- Connect the motor driver and confirm forward, reverse, left and right movement.
- Connect the distance sensor and display raw distance readings.
- Add the left/right target-detection sensors and test them separately.
- Write simple following logic with a safe minimum distance.
- Test at low speed with one person or a clear target.
- Tune sensor position, thresholds and motor speed.
- Add labels and a block diagram for the final demonstration.
Common mistakes to avoid
- Trying to solve distance and direction at the same time before testing sensors separately
- Using high speed during early testing
- Setting the minimum following distance too small
- Expecting basic IR sensors to identify a specific person
- Using unstable power that resets the controller when motors start
Frequently asked questions
Can the robot recognise a particular person?
Not with simple IR and ultrasonic sensors. Person recognition would require more advanced vision or identification methods.
Why does the robot lose the target?
Basic sensors have limited field of view and can be affected by target angle, background objects and lighting.
Can I use a camera instead?
Yes, but computer-vision tracking is a more advanced project and requires greater processing power and software complexity.
Conclusion
Build a reliable low-speed following demonstration first. Understanding the sensor limitations is part of the robotics learning, not a failure of the project.
Madras Academy project tip: add a block diagram, component labels, photos of testing, a simple results table and two or three viva answers. That makes the project easier to explain and shows genuine understanding.
