Building A Simple Arduino Robot

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Introduction

Building a simple Arduino robot is an excellent beginner project for anyone interested in robotics, electronics, or programming. This guide will walk you through the process of assembling a basic two-wheeled robot that can move forward, backward, and turn, all controlled by an Arduino microcontroller. You’ll learn about the necessary hardware, wiring, and programming required to bring your robot to life. This project is ideal for students, hobbyists, or anyone looking to get hands-on experience with Arduino and robotics.

Time Estimate

Assembly and wiring: 1.5–2 hours
Programming and testing: 1 hour
Total estimated time: 2.5–3 hours

Material List

Arduino Uno board – approx. €20
USB cable for Arduino – included with most Arduino kits
2x DC gear motors with wheels – approx. €10
Motor driver module (L298N or similar) – approx. €6
Robot chassis (acrylic or plastic, with mounting hardware) – approx. €10
1x caster wheel (for balance) – approx. €2
1x 4xAA battery holder and 4x AA batteries – approx. €4
Jumper wires (male-to-male and female-to-male) – approx. €3
Small screwdriver and double-sided tape or screws – approx. €2
Optional: Ultrasonic sensor (HC-SR04) for obstacle avoidance – approx. €3

Total estimated cost: €60

Step-by-Step Guide

1. Prepare the Robot Chassis

Unpack the robot chassis kit and identify all parts: base plate, motor mounts, screws, and wheels.
Attach the DC gear motors to the chassis using the provided screws or brackets.
Mount the caster wheel at the front or rear (depending on design) for stability.
Ensure all components are securely fastened and the wheels spin freely.

Preparing and assembling the robot chassis

2. Install the Wheels and Battery Holder

Push the wheels onto the shafts of the DC motors until they fit snugly.
Attach the battery holder to the chassis using double-sided tape or screws, ensuring easy access for battery replacement.
Route the battery holder’s wires toward the area where the Arduino and motor driver will be mounted.

Installing wheels and battery holder on the robot chassis

3. Mount the Arduino and Motor Driver

Place the Arduino Uno board on the chassis, securing it with screws or tape.
Mount the L298N motor driver module next to the Arduino, ensuring the terminals are accessible.
Leave enough space between components for wiring and airflow.

Mounting Arduino Uno and L298N motor driver on the chassis

4. Connect the Motors to the Motor Driver

Connect the left motor’s wires to the OUT1 and OUT2 terminals of the L298N module.
Connect the right motor’s wires to the OUT3 and OUT4 terminals.
Double-check the polarity: if the wheels spin in the wrong direction later, you can swap the wires.

Connecting DC motors to the motor driver module

5. Wire the Motor Driver to the Arduino

Use jumper wires to connect the IN1, IN2, IN3, and IN4 pins of the L298N to Arduino digital pins (e.g., 8, 9, 10, 11).
Connect the ENA and ENB pins to Arduino PWM-capable pins (e.g., 5 and 6) for speed control.
Connect the GND of the L298N to the Arduino GND.

Wiring the motor driver module to the Arduino board

6. Power Connections

Connect the battery holder’s positive (red) wire to the 12V input on the L298N module.
Connect the battery holder’s negative (black) wire to the GND on the L298N.
Use the 5V output from the L298N to power the Arduino’s 5V pin, or power the Arduino separately via USB during programming.

Connecting battery power to the motor driver and Arduino

7. (Optional) Add an Ultrasonic Sensor for Obstacle Avoidance

Mount the HC-SR04 ultrasonic sensor at the front of the robot using a bracket or tape.
Connect the VCC and GND pins to the Arduino’s 5V and GND.
Connect the TRIG and ECHO pins to two available Arduino digital pins (e.g., 7 and 6).

Adding an ultrasonic sensor to the robot for obstacle detection

8. Upload the Arduino Code

Connect the Arduino to your computer using the USB cable.
Open the Arduino IDE and paste the following sample code to control the motors:

#define ENA 5
#define ENB 6
#define IN1 8
#define IN2 9
#define IN3 10
#define IN4 11

void setup() {
  pinMode(ENA, OUTPUT);
  pinMode(ENB, OUTPUT);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);
}

void loop() {
  // Move forward
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
  analogWrite(ENA, 200);
  analogWrite(ENB, 200);
  delay(2000);

  // Stop
  analogWrite(ENA, 0);
  analogWrite(ENB, 0);
  delay(1000);

  // Move backward
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH);
  analogWrite(ENA, 200);
  analogWrite(ENB, 200);
  delay(2000);

  // Stop
  analogWrite(ENA, 0);
  analogWrite(ENB, 0);
  delay(1000);
}

Select the correct board and port, then upload the code to your Arduino.
Disconnect the USB cable after uploading.

9. Test the Robot’s Movement

Place the robot on a flat, clear surface.
Turn on the battery pack to power the robot.
Observe the robot as it moves forward, stops, moves backward, and stops again according to the uploaded code.
If the robot does not move as expected, check all wiring and code.

Testing the robot’s movement on a flat surface

10. (Optional) Program Obstacle Avoidance

If you installed the ultrasonic sensor, modify the code to read distance and stop or turn when an obstacle is detected.
Example code snippet for obstacle detection:

#define TRIG 7
#define ECHO 6

long duration;
int distance;

void loop() {
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);

  duration = pulseIn(ECHO, HIGH);
  distance = duration * 0.034 / 2;

  if (distance < 20) {
    // Stop or turn
    analogWrite(ENA, 0);
    analogWrite(ENB, 0);
    delay(500);
    // Add turning code here
  } else {
    // Move forward
    digitalWrite(IN1, HIGH);
    digitalWrite(IN2, LOW);
    digitalWrite(IN3, HIGH);
    digitalWrite(IN4, LOW);
    analogWrite(ENA, 200);
    analogWrite(ENB, 200);
  }
}

Upload the modified code and test the robot’s obstacle avoidance behavior.

Programming and testing obstacle avoidance with ultrasonic sensor

Tips

Use color-coded jumper wires to keep your wiring organized and troubleshooting easier.
Secure all components firmly to the chassis to prevent vibrations or loose connections during movement.
Start with simple movement code and gradually add features like obstacle avoidance or remote control as you gain confidence.