Human Following Robot

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Overview / Introduction

The Human Following Robot is a simple and intelligent robot that uses three infrared sensors to follow a person (or any black path/leg) by detecting direction and movement. This project utilizes an Arduino Uno, IR sensors, and a motor driver to dynamically control the robot's motion — forward, left, or right — based on the relative position of a moving object or a central signal detected by the IR sensors.

Features

• Follows a person or object using three IR sensors
• Smart decision-making: turns left, right, or moves straight
• Controlled by L298N Motor Driver
• Real-time detection using digital IR sensors
• Easy to build and modify

Hardware Components

Component	Quantity
Arduino UNO	1
IR Sensors	3
L298N Motor Driver	1
DC Motors	4
Robot Chassis	1
Wheels	4
Jumper Wires	-
Power Supply (Battery Pack)	1

Software Requirements

• Arduino IDE
• Arduino Board Library
• USB Cable for Arduino
• Serial Monitor (for debugging, optional)

Pin Configuration

Function	Arduino Pin
Left IR Sensor	D3
Right IR Sensor	D2
Middle IR Sensor	D4
Left Motor Enable	D10
Left Motor IN1	D9
Left Motor IN2	D8
Right Motor Enable	D5
Right Motor IN1	D7
Right Motor IN2	D6

Decision-Making Logic

• Middle IR sensor LOW → Go Forward
• Left IR sensor LOW, Right HIGH → Turn Left
• Right IR sensor LOW, Left HIGH → Turn Right
• All sensors HIGH → Stop (Lost track)

Function Descriptions

• goForward() — Sets both motors to move forward at defined speed
• turnLeft() — Rotates the robot to the left
• turnRight() — Rotates the robot to the right
• stopMotors() — Halts all motor movement

How to Run

1. Assemble all components as per the wiring table.
2. Open Arduino IDE and paste the code.
3. Upload the code to your Arduino UNO board.
4. Place the robot in front of a human leg or dark object.
5. Power the robot and watch it follow the target!

Sensors & Motor Driver Explained

IR Sensors

The robot uses three IR sensors (Left, Middle, Right) to detect reflected IR light. These sensors work based on infrared reflection:

• White/Reflective surface → Reflects IR → Sensor reads LOW
• Black/Absorptive surface (like clothes) → Absorbs IR → Sensor reads HIGH
• The robot compares values from all three sensors to detect which direction to move in to follow a person or leg.

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L298N Motor Driver

The L298N Motor Driver Module is used to control the two DC motors of the robot. It acts as an interface between the low-power Arduino and the high-power motors.

Features:

• Can control the direction and speed of two DC motors.
• Accepts PWM (Pulse Width Modulation) signals from Arduino to adjust motor speed.
• Has two enable pins (ENA, ENB) and four control pins (IN1, IN2, IN3, IN4) connected to the Arduino.

Working:

• ENA / ENB: Used to control the speed of motors via analogWrite().
• IN1/IN2 (for Motor A) and IN3/IN4 (for Motor B): Used to control motor direction via digitalWrite().

Example:

digitalWrite(IN1, HIGH);
digitalWrite(IN2, LOW);  // Motor moves forward

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How to Charge Lithium-Ion

What You Need:

• TP4056 charging module (with or without protection circuit)
• Lithium-Ion battery (typically 3.7V, like an 18650 cell)
• Power source (5V via USB cable or 5V adapter)

Wiring Connections

TP4056 Pin	Connects To	Description
BAT+	Battery Positive (+)	Connect to battery's positive terminal
BAT-	Battery Negative (–)	Connect to battery's negative terminal
IN+	5V Power Positive	USB VCC or 5V adapter
IN-	5V Power Ground	USB GND or adapter GND
OUT+	Output Positive (Optional)	Same as BAT+ if present
OUT-	Output Negative (Optional)	Same as BAT– if present

Charging Status (LED Indicators)

• 🔴 Red LED ON → Charging
• 🟢 Blue/Green LED ON → Fully Charged (approx. 4.2V)

TP4056 Specifications

• Input Voltage: 4.5V – 5.5V (recommended: 5V)
• Charging Cut-off Voltage: 4.2V
• Max Charging Current: 1A (default, adjustable by changing onboard resistor)

Charging Steps

1. Connect BAT+ and BAT- to the Lithium-ion battery terminals.
2. Connect IN+ and IN- to a 5V power supply (USB or adapter).
3. Observe LED indicators:
   • Red = Charging
   • Green/Blue = Fully Charged
4. Disconnect power once fully charged (unless using protected module).

Safety Tips

• Never leave charging unattended.
• Use only genuine 3.7V Li-ion batteries.
• Avoid short circuits on BAT terminals.
• Do not reverse polarity — it can damage the module and the battery.
• Use TP4056 with protection for safer charging and discharging.

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Demonstration

The robot will continuously monitor IR input and follow a dark object/person as long as it's in front of the middle sensor.

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Applications

• Human-following carts or luggage
• Shopping assistants in stores
• Personal delivery bots
• Educational robotic kits

Future Improvements

➕ Implement PID control for smoother and more accurate tracking
➕ Upgrade to vision-based tracking using OpenCV or AI camera

Troubleshooting / Common Issues

• Robot not moving → Check motor power supply and enable pins.
• Sensors not responding → Ensure proper alignment and correct logic levels.
• Wrong turns → Swap motor direction pins or verify sensor logic.
• Low speed or stalling → Check battery voltage and motor connections.

Demo Video

https://github.com/user-attachments/assets/1a332b06-d684-478d-a12b-91c1f452c24d

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Credits / Acknowledgements

Developed by Awais Asghar and Muhammad Abdullah

License

This project is licensed under the MIT License. You are free to use, modify, and distribute it with attribution.

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