Obstacle avoidance is a crucial feature in robotics, enabling autonomous robots to navigate environments without colliding with obstacles. This capability is essential for applications ranging from simple hobbyist robots to complex industrial automation systems. Using Arduino, a popular open-source electronics platform, we can develop an effective obstacle avoidance system. This article will guide you through the process, providing detailed instructions and code examples to help you get started.

Projeto: In this project, we will build a simple obstacle avoidance robot using an Arduino board and an ultrasonic sensor. The robot will be able to detect obstacles in its path and change direction to avoid collisions. The main objectives are:

1. Detect obstacles using an ultrasonic sensor.
2. Control the movement of the robot using DC motors.
3. Implement a basic algorithm for obstacle avoidance.

Lista de componentes:

• 1 x Arduino Uno
• 1 x Ultrasonic Sensor (HC-SR04)
• 2 x DC Motors
• 1 x Motor Driver (L298N)
• 1 x Chassis for the robot
• 1 x Battery pack (appropriate for your motors and Arduino)
• Jumper wires
• Breadboard (optional)

Exemplos:

1. Wiring the Components:

   • Connect the ultrasonic sensor to the Arduino:
     • VCC to 5V
     • GND to GND
     • Trig to digital pin 9
     • Echo to digital pin 10
   • Connect the motor driver to the Arduino and the motors:
     • IN1 to digital pin 2
     • IN2 to digital pin 3
     • IN3 to digital pin 4
     • IN4 to digital pin 5
     • ENA to digital pin 6
     • ENB to digital pin 7
     • Motor A to OUT1 and OUT2
     • Motor B to OUT3 and OUT4
     • VCC to 12V (or appropriate voltage for your motors)
     • GND to GND

2. Arduino Code:

   // Define pins for ultrasonic sensor
   const int trigPin = 9;
   const int echoPin = 10;
   
   // Define pins for motor driver
   const int motorA1 = 2;
   const int motorA2 = 3;
   const int motorB1 = 4;
   const int motorB2 = 5;
   const int enableA = 6;
   const int enableB = 7;
   
   void setup() {
    // Initialize serial communication
    Serial.begin(9600);
   
    // Set motor driver pins as outputs
    pinMode(motorA1, OUTPUT);
    pinMode(motorA2, OUTPUT);
    pinMode(motorB1, OUTPUT);
    pinMode(motorB2, OUTPUT);
    pinMode(enableA, OUTPUT);
    pinMode(enableB, OUTPUT);
   
    // Set ultrasonic sensor pins
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
   }
   
   void loop() {
    // Get distance from ultrasonic sensor
    long duration, distance;
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    distance = (duration / 2) / 29.1;
   
    // Print distance to serial monitor
    Serial.print("Distance: ");
    Serial.println(distance);
   
    // Obstacle avoidance logic
    if (distance < 20) {
      // Stop motors
      digitalWrite(motorA1, LOW);
      digitalWrite(motorA2, LOW);
      digitalWrite(motorB1, LOW);
      digitalWrite(motorB2, LOW);
      delay(500);
   
      // Turn right
      digitalWrite(motorA1, HIGH);
      digitalWrite(motorA2, LOW);
      digitalWrite(motorB1, LOW);
      digitalWrite(motorB2, HIGH);
      delay(1000);
    } else {
      // Move forward
      digitalWrite(motorA1, HIGH);
      digitalWrite(motorA2, LOW);
      digitalWrite(motorB1, HIGH);
      digitalWrite(motorB2, LOW);
    }
   
    delay(100);
   }

   Explanation of the Code:

   • The ultrasonic sensor is used to measure the distance to the nearest obstacle.
   • If an obstacle is detected within 20 cm, the robot stops and turns right.
   • If no obstacle is detected, the robot moves forward.
   • The motor driver controls the direction and speed of the DC motors.