Arduino

How to build an obstacle avoidance robot with Arduino

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By Jackson Taylor

Building an obstacle avoidance robot with Arduino is an exciting and educational project. This type of robot uses sensors to detect and avoid obstacles in its path, making it an excellent hands-on experience for learning about robotics and electronics. In this article, we will guide you step by step on how to build your own obstacle-avoidance robot using an Arduino board.

What You Will Need

Before you start building your robot, it’s important to gather all the necessary components. Here’s a list of what you’ll need:
  • Arduino UNO board
  • Ultrasonic sensor (HC-SR04)
  • DC motors with motor driver module (L298N)
  • Wheels and chassis
  • Jumper wires
  • Battery pack
  • Breadboard (optional)
  • Motor driver (L298N or similar)
  • Power supply

Step 1: Set Up the Arduino Board

The Arduino UNO will serve as the brain of your robot. Begin by connecting the Arduino board to your computer using a USB cable. Install the necessary Arduino IDE on your computer to write and upload code to the board.

Step 2: Wiring the Motor Driver

To control the motors, you’ll need a motor driver. The L298N is a popular motor driver that can control both the direction and speed of the DC motors.
  1. Connect the power pins: Connect the VCC and GND pins of the L298N to your power source (usually 5V and ground).
  2. Motor connections: Connect the OUT1 and OUT2 pins of the L298N to the terminals of the first motor, and OUT3 and OUT4 to the second motor.
  3. Control pins: Connect the IN1, IN2, IN3, and IN4 pins to the Arduino digital pins (you will specify the exact pins in the code later).

Step 3: Connecting the Ultrasonic Sensor

The ultrasonic sensor (HC-SR04) is essential for detecting obstacles in front of your robot. It sends out a pulse and calculates the time it takes for the pulse to bounce back from an obstacle, thus determining the distance.
  1. VCC and GND connections: Connect the VCC and GND of the ultrasonic sensor to the power and ground on the Arduino.
  2. Trigger and Echo pins: Connect the Trigger pin to an Arduino digital pin (for example, pin 9), and the Echo pin to another digital pin (for example, pin 10).
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Step 4: Assemble the Robot Chassis and Motors

Now it’s time to assemble the physical body of the robot. Mount the motors and wheels onto the robot chassis. Make sure the motors are securely attached and aligned so the robot can move smoothly. The wheels will be powered by the DC motors and controlled by the motor driver.

Step 5: Powering the Robot

You will need a power source to run both the Arduino and the motors. A typical setup involves using a battery pack that connects to the Arduino’s Vin pin (for the Arduino) and the motor driver module. Ensure that the power supply voltage matches the requirements of the components.

Writing the Code for Your Obstacle Avoidance Robot

With all the hardware set up, the next step is to program the Arduino board. Below is a simple code that will enable the robot to avoid obstacles by moving forward until an obstacle is detected.
cpp
#include <AFMotor.h> #define trigPin 9 #define echoPin 10 #define motor1Pin1 3 #define motor1Pin2 4 #define motor2Pin1 5 #define motor2Pin2 6 long duration; int distance; void setup() { Serial.begin(9600); pinMode(trigPin, OUTPUT); pinMode(echoPin, INPUT); // Initialize motors AFMotor motor1(motor1Pin1, motor1Pin2); AFMotor motor2(motor2Pin1, motor2Pin2); } void loop() { // Send pulse from ultrasonic sensor digitalWrite(trigPin, LOW); delayMicroseconds(2); digitalWrite(trigPin, HIGH); delayMicroseconds(10); digitalWrite(trigPin, LOW); duration = pulseIn(echoPin, HIGH); distance = (duration / 2) * 0.0344; if (distance > 10) { motor1.setSpeed(255); motor2.setSpeed(255); motor1.run(FORWARD); motor2.run(FORWARD); } else { motor1.run(RELEASE); motor2.run(RELEASE); } }

How the Code Works

  • The trigPin sends a pulse to the ultrasonic sensor to measure the distance to the nearest object.
  • If the object is detected within 10 cm, the motors stop. Otherwise, the motors continue moving the robot forward.

Step 6: Testing Your Robot

Once you upload the code to your Arduino, it’s time to test your robot. Place the robot on a flat surface and power it up. The robot should start moving forward. If it detects an obstacle in its path, it will stop.
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Step 7: Fine-Tuning the Robot’s Performance

You can fine-tune your robot’s performance by adjusting the code. For example, you can program the robot to turn when it detects an obstacle, or even add additional sensors to make the robot more efficient. Experiment with the sensor range, speed, and turning behavior to get the best results.

Enhancing the Robot’s Functionality

Now that you have your basic obstacle-avoidance robot running, there are many ways you can improve its functionality:

Adding More Sensors for Better Detection

You can add additional ultrasonic sensors to the front, sides, and back of your robot for better coverage and to avoid obstacles from all directions.

Improving Navigation Algorithms

Advanced algorithms, like PID (Proportional-Integral-Derivative) control, can help improve the navigation and movement of your robot. This would allow for smoother turns and better obstacle detection.

Using Bluetooth for Remote Control

You can add a Bluetooth module (like the HC-05) to your robot and control it remotely via a smartphone or computer. This gives you more flexibility in controlling the robot’s movement.

Battery Management System

For longer operational times, consider integrating a battery management system (BMS) to monitor the battery level and manage power usage efficiently.

Conclusion

Building an obstacle avoidance robot with Arduino is a fantastic project for anyone interested in robotics and electronics. By following the steps outlined in this article, you’ll have a working robot in no time. Whether you’re a beginner or an experienced maker, this project will teach you valuable skills that can be applied to more complex robotics projects in the future. With some fine-tuning and creative upgrades, your robot can become even smarter and more versatile. So, gather your materials, write the code, and start building your very own Arduino-powered obstacle-avoidance robot!

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