Obstacle-Avoiding Robot

Files

• README.md
• ObstacleAvoidingRobot.ino

1. Concept

A two-wheel differential drive rover that roams autonomously, uses an HC-SR04 ultrasonic sensor to detect obstacles ahead, and an MPU-6050 IMU to monitor tilt (prevent tipping). On obstacle detection it stops, reverses, turns randomly left or right, then resumes. If it tilts beyond a safety angle, it immediately halts.

Key Behaviors

1. Forward Patrol at constant speed.
2. Obstacle Avoidance:
   • If distance < 20 cm ➔ Stop ➔ Reverse ➔ Turn (random) ➔ Resume.
3. Tilt Safety:
   • If roll or pitch > 30° ➔ Emergency stop.

2. Bill of Materials

• 1 × Arduino Uno (or Nano)
• 1 × L298N dual H-bridge motor driver
• 2 × DC gear motors + wheels
• 1 × HC-SR04 ultrasonic distance sensor
• 1 × MPU-6050 6-axis IMU
• Chassis, caster wheel, battery pack (7.4 V Li-ion or 6×AA)
• Jumper wires, solderless breadboard (optional)

3. Wiring Diagram

Arduino Uno                L298N Motor Driver         Motor A  
┌──────────────┐           ┌────────────────┐        ┌─────┐
│ D2  ─────► IN1 │──►      │ IN1            │──►    │ M+  │
│ D3  ─────► IN2 │──►      │ IN2            │──►    │ M-  │
│ D5 (PWM)► ENA │──►       │ ENA            │
└──────────────┘           └────────────────┘        └─────┘

Arduino Uno                L298N Motor Driver         Motor B  
┌──────────────┐           ┌────────────────┐        ┌─────┐
│ D4  ─────► IN3 │──►      │ IN3            │──►    │ M+  │
│ D7  ─────► IN4 │──►      │ IN4            │──►    │ M-  │
│ D6 (PWM)► ENB │──►       │ ENB            │
└──────────────┘           └────────────────┘        └─────┘

HC-SR04:
┌──────────────┐
│ D8 ──► Trig  │
│ D9 ──► Echo  │
└──────────────┘

MPU-6050 (I²C):
┌──────────────┐
│ A4 ──► SDA   │
│ A5 ──► SCL   │
│ 5V ──► VCC   │
│ GND─► GND    │
└──────────────┘

Power: Drive motors from battery pack; power Arduino and sensors from 5 V regulator.

4. Software Setup

1. In Arduino IDE install libraries:
   • NewPing by Tim Eckel
   • I2Cdev & MPU6050 (Jeff Rowberg’s I2CdevLib)
2. Create project folder ObstacleAvoidingRobot and add both files.
3. Open ObstacleAvoidingRobot.ino in Arduino IDE.
4. Select Arduino Uno (or Nano) and correct COM port.

5. Operation

1. Power on. Robot begins forward at MOTOR_SPEED.
2. If obstacle < DIST_THRESHOLD cm:
   • Stops ➔ reverses REVERSE_TIME ms ➔ random turn left/right for TURN_TIME ms ➔ resumes.
3. If tilt > TILT_LIMIT ° in any axis:
   • Immediate full stop. Re-enable by power-cycle.

Say continua to move on to project #7!