This project creates an autonomous human-following robot using Arduino UNO and three ultrasonic sensors. The robot can track and follow a person by measuring distances in three directions (front, left, and right) and making intelligent movement decisions based on sensor data.
- Three-sensor setup for 360-degree human identification
- Real-time distance measurement and decision-making
- Autonomous navigation without human assistance
- Collision avoidance and safe following distance maintenance
- Bidirectional movement (forward, backward, left, right)
- Automatic stopping when target is out of range
| Component | Quantity | Description |
|---|---|---|
| Arduino UNO | 1 | Main microcontroller |
| HC-SR04 Ultrasonic Sensor | 3 | Distance measurement |
| L298N Motor Driver | 1 | Motor control |
| BO Motors | 2 | Drive motors |
| Wheels | 2 | Robot movement |
| Li-ion Battery 3.7V | 2 | Power supply |
| Battery Holder | 1 | Battery mounting |
| Robot Chassis | 1 | Robot frame |
| Breadboard | 1 | Circuit connections |
| Ultrasonic Sensor Holders | 3 | Sensor mounting |
| Switch | 1 | Power control |
| Jumper Wires | - | Connections |
| Sensor | Arduino Pin | HC-SR04 Pin |
|---|---|---|
| Sensor 1 (Front) | Pin 2 | TRIG |
| Sensor 1 (Front) | Pin 3 | ECHO |
| Sensor 2 (Left) | Pin 4 | TRIG |
| Sensor 2 (Left) | Pin 5 | ECHO |
| Sensor 3 (Right) | Pin 6 | TRIG |
| Sensor 3 (Right) | Pin 7 | ECHO |
| All Sensors | 5V | VCC |
| All Sensors | GND | GND |
| Arduino Pin | L298N Pin |
|---|---|
| Pin 8 | IN1 |
| Pin 9 | IN2 |
| Pin 10 | IN3 |
| Pin 11 | IN4 |
| 5V | VCC |
| GND | GND |
| L298N Pin | Connection |
|---|---|
| OUT1 | Left Motor + |
| OUT2 | Left Motor - |
| OUT3 | Right Motor + |
| OUT4 | Right Motor - |
- Connect 2x 3.7V Li-ion batteries in series (7.4V total)
- Connect positive terminal to L298N +12V input
- Connect negative terminal to L298N GND
- Use switch for power control
#define MAX_DISTANCE 40 // Maximum following distance (cm)
#define MIN_DISTANCE_BACK 5 // Minimum distance before backing up (cm)#define MAX_SPEED 150 // Maximum motor speed (0-255)
#define MIN_SPEED 75 // Minimum motor speed (0-255)- Distance Measurement: Three ultrasonic sensors continuously measure distances in front, left, and right directions
- Decision Making: Arduino processes sensor data and determines the closest object/person
- Movement Control: Based on sensor readings, the robot:
- Moves forward if person is directly ahead
- Turns left if person is on the left side
- Turns right if person is on the right side
- Moves backward if too close to avoid collision
- Stops if no person is detected within range
-
Hardware Assembly:
- Mount ultrasonic sensors on robot chassis
- Connect components according to circuit diagram
- Secure batteries and ensure proper power connections
-
Software Setup:
- Install Arduino IDE
- Connect Arduino UNO to computer
- Upload the provided code
- Open Serial Monitor for debugging
-
Calibration:
- Adjust
MAX_DISTANCEandMIN_DISTANCE_BACKvalues based on your requirements - Fine-tune motor speeds for optimal performance
- Test in open area for proper functionality
- Adjust
- Power on the robot using the switch
- The robot will start scanning for objects/persons
- Stand in front of the robot within the detection range
- The robot will automatically follow your movement
- Move slowly to allow the robot to track properly
- Robot doesn't move: Check motor connections and battery voltage
- Sensors not working: Verify ultrasonic sensor connections and power supply
- Moves in wrong direction: Check motor wiring polarity
- Erratic behavior: Ensure proper grounding and stable power supply
- Use Serial Monitor (9600 baud) to view sensor readings
- Check distance values for all three sensors
- Verify movement commands in serial output
- Retail: Shopping cart robots in malls
- Hospitality: Luggage-carrying robots in airports/hotels
- Security: Patrol robots for surveillance
- Healthcare: Elderly care assistance robots
- Education: Learning and demonstration projects
- Entertainment: Interactive companion robots
- Always test in open areas first
- Ensure emergency stop mechanism
- Monitor battery levels regularly
- Keep safe distance during operation
- Avoid testing near stairs or hazardous areas
- Add camera for visual tracking
- Implement voice control features
- Add obstacle avoidance algorithms
- Integrate GPS for outdoor navigation
- Add smartphone app control
- Implement machine learning for better tracking
- Original Tutorial: Human Following Robot Using Arduino and Ultrasonic Sensor
- Arduino Documentation: arduino.cc
- HC-SR04 Datasheet: Ultrasonic sensor specifications
- L298N Motor Driver Guide: Motor control documentation
This project is open-source and available under the MIT License.
Contributions are welcome! Please feel free to submit issues, feature requests, or pull requests.
Note: This project is intended for educational and hobbyist purposes. Always follow safety guidelines when working with electronics and mechanical components.