How to Build a Simple Robot with Arduino

How to Build a Simple Robot with Arduino: Step-by-Step Guide

Table of Contents

- Introduction

- What You'll Need

- Understanding the Components

- Setting Up Your Arduino Environment

- Building the Robot Chassis

- Wiring the Motors and Motor Driver

- Adding Sensors

- The Complete Circuit Diagram

- Programming Your Robot

- Testing and Troubleshooting

- Expanding Your Robot's Capabilities

- Conclusion

Introduction

Building your first robot is an exciting milestone in any maker's journey. While professional robotics can be complex, creating a simple yet functional robot with Arduino is achievable even for beginners. This hands-on project will teach you fundamental concepts in electronics, programming, and mechanical design—all valuable skills in today's technology-driven world.

In this comprehensive guide, we'll walk through the process of building a basic two-wheeled robot that can navigate autonomously using sensors to detect and avoid obstacles. By the end, you'll have a working robot and the knowledge to expand its capabilities further.

Let's get started on your robotics journey!

What You'll Need

Hardware Components

Component | Quantity | Approximate Cost | Purpose

---------|----------|------------------|---------

Arduino Uno | 1 | $23 | Main controller board

L298N Motor Driver | 1 | $5 | Controls the DC motors

DC Gear Motors | 2 | $8 (pair) | Provide movement

Wheels | 2 | $5 (pair) | Attached to motors

Caster Wheel | 1 | $3 | Third point of contact for balance

HC-SR04 Ultrasonic Sensor | 1 | $3 | Detects obstacles

Breadboard | 1 | $5 | For prototyping connections

Jumper Wires | 1 pack | $5 | Connect components

Battery Holder (for 4 AA batteries) | 1 | $2 | Powers the motors

AA Batteries | 4 | $4 | Power source

Robot Chassis | 1 | $10 (or DIY) | Base structure for the robot

Power Bank (optional) | 1 | $15 | Alternative power for Arduino

Small Screws and Nuts | Various | $3 | Securing components

Total Approximate Cost: $76-$91

Tools

- Screwdriver set

- Wire cutters/strippers

- Hot glue gun or strong adhesive

- Drilling tool (if making a DIY chassis)

- Computer with USB port (for programming Arduino)

Software

- Arduino IDE (free download from https://www.arduino.cc/en/software)

Understanding the Components

Before we start building, let's understand the key components and their roles:

Arduino Uno

The Arduino Uno is a microcontroller board based on the ATmega328P. It serves as the brain of the robot, processing sensor inputs, making decisions based on programming, and controlling motors and outputs. It features digital and analog pins for component interaction.

L298N Motor Driver

This component is essential because Arduino pins cannot drive motors directly. The motor driver acts as an intermediary, providing necessary power and enabling speed control and direction reversal.

DC Gear Motors

These motors provide mechanical power. The gearbox increases torque, and 100-300 RPM motors are ideal for small robots.

HC-SR04 Ultrasonic Sensor

This sensor detects obstacles using sound waves, measuring distances from 2cm to 400cm to help the robot navigate.

Setting Up Your Arduino Environment

1. Install Arduino IDE from the official website.

2. Connect Arduino to your computer via USB.

3. Test the setup by uploading the Blink example from File > Examples > 01.Basics > Blink. The onboard LED should blink, confirming proper setup.

Building the Robot Chassis

Options: Use a pre-made chassis kit or create a DIY version (15cm x 10cm base). Attach motors at the back/sides, a caster wheel for balance, and ensure space for components. Secure motors and wheels using screws or adhesive.

Wiring the Motors and Motor Driver

1. Connect L298N pins to Arduino: ENA(5), IN1(6), IN2(7), IN3(8), IN4(9), ENB(10), and GND.

2. Wire motors to L298N outputs: Right motor to OUT1/OUT2, left motor to OUT3/OUT4.

3. Power the motor driver with 6-12V batteries and optionally use a power bank for the Arduino.

Adding Sensors

Mount the HC-SR04 sensor facing forward. Connect VCC to 5V, GND to GND, TRIG to pin 2, and ECHO to pin 3.

The Complete Circuit Diagram

Arduino Uno Connections:

- Pin 5 → L298N ENA

- Pin 6 → L298N IN1

- Pin 7 → L298N IN2

- Pin 8 → L298N IN3

- Pin 9 → L298N IN4

- Pin 10 → L298N ENB

- Pin 2 → HC-SR04 TRIG

- Pin 3 → HC-SR04 ECHO

- 5V → HC-SR04 VCC

- GND → Shared GND for sensor and motor driver

L298N Connections:

- OUT1/OUT2 → Right Motor

- OUT3/OUT4 → Left Motor

- 12V/GND → Battery Pack

Programming Your Robot

Upload this obstacle-avoidance code:

const int trigPin = 2;

const int echoPin = 3;

const int enA = 5;

const int in1 = 6;

const int in2 = 7;

const int in3 = 8;

const int in4 = 9;

const int enB = 10;

long duration;

int distance;

int safetyDistance = 20;

void setup() {

  Serial.begin(9600);

  pinMode(enA, OUTPUT);

  pinMode(enB, OUTPUT);

  pinMode(in1, OUTPUT);

  pinMode(in2, OUTPUT);

  pinMode(in3, OUTPUT);

  pinMode(in4, OUTPUT);

  pinMode(trigPin, OUTPUT);

  pinMode(echoPin, INPUT);

}

void loop() {

  digitalWrite(trigPin, LOW);

  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);

  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);

  

  duration = pulseIn(echoPin, HIGH);

  distance = duration * 0.034 / 2;

  

  Serial.print("Distance: ");

  Serial.println(distance);

  

  if (distance <= safetyDistance) {

    digitalWrite(in1, LOW);

    digitalWrite(in2, LOW);

    digitalWrite(in3, LOW);

    digitalWrite(in4, LOW);

    delay(500);

    

    digitalWrite(in2, HIGH);

    digitalWrite(in4, HIGH);

    analogWrite(enA, 200);

    analogWrite(enB, 200);

    delay(1000);

    

    digitalWrite(in1, HIGH);

    digitalWrite(in4, HIGH);

    analogWrite(enA, 200);

    analogWrite(enB, 200);

    delay(800);

  }

  else {

    digitalWrite(in1, HIGH);

    digitalWrite(in3, HIGH);

    analogWrite(enA, 150);

    analogWrite(enB, 150);

  }

}

Testing and Troubleshooting

Test the robot by powering it with batteries. Expected behavior: moves forward, stops/backs up/turns when detecting obstacles. Common fixes: check battery voltage, motor connections, sensor alignment, and code uploads.

Expanding Your Robot's Capabilities

Enhancements:

- Additional sensors: line-following, IR, light

- Navigation upgrades: encoders, Bluetooth control

- Outputs: buzzers, LEDs, LCD displays

- Structural improvements: 3D-printed parts, protective shells

- Advanced programming: PID control, mapping

Conclusion

You’ve built a functional Arduino robot, learning electronics, programming, and mechanical assembly. Continue iterating by adding features or refining design. Explore more projects to expand your skills in robotics.

This guide is part of our DIY Robotics for Beginners series. Explore other articles for more project ideas.

Keywords: Arduino robot, beginner project, DIY robot, obstacle avoidance, L298N motor driver, HC-SR04 sensor, robotics guide, Arduino tutorial