Building Simple Robots

Building a robot is one of the most exciting things you can do as a beginner in robotics.

A simple robot combines electronics, programming, and mechanical assembly into one project.

This guide will walk you through building a basic two-wheel robot that can move forward, backward, and turn.

You do not need any prior experience. We will explain every step clearly.

The chassis is the body of your robot. It holds all the components together.

You can buy a ready-made robot chassis kit or make one from cardboard or acrylic sheet.

Attach the two DC motors to the back of the chassis using screws or hot glue.

Attach the wheels to the motor shafts.

Attach the caster wheel to the front of the chassis for balance.

Make sure the motors are aligned properly so the robot moves straight.

The L298N motor driver connects between the Arduino and the motors.

It allows Arduino to control the speed and direction of both motors.

Wiring connections:

• Motor A wires to OUT1 and OUT2 on the L298N
• Motor B wires to OUT3 and OUT4 on the L298N
• Battery positive to 12V input on L298N
• Battery negative to GND on L298N
• L298N GND to Arduino GND
• IN1, IN2, IN3, IN4 to Arduino digital pins (e.g., pins 5, 6, 9, 10)
• ENA and ENB to Arduino PWM pins for speed control

Double-check all connections before powering on to avoid damage.

The Arduino code tells the robot how to move. Here is a simple explanation of the logic:

To move forward: both motors spin in the same direction.

To move backward: both motors spin in the opposite direction.

To turn left: the right motor spins forward while the left motor stops or spins backward.

To turn right: the left motor spins forward while the right motor stops or spins backward.

The basic code structure uses digitalWrite() to set motor direction and analogWrite() to control speed.

Upload the code to Arduino using the USB cable and Arduino IDE software.

Connect the battery to the motor driver.

Place the robot on a flat surface.

Turn on the power and observe the robot's movement.

If the robot does not move straight, check if both motors are spinning in the correct direction.

You may need to swap the motor wires on the L298N if a motor spins the wrong way.

Adjust the speed values in your code to make the robot move at a comfortable pace.

Once your basic robot works, you can add an ultrasonic sensor to detect obstacles.

Mount the HC-SR04 sensor on the front of the robot.

Connect the sensor to Arduino: VCC to 5V, GND to GND, Trig and Echo to digital pins.

In your code, read the distance from the sensor. If an object is closer than 20cm, make the robot stop and turn.

This turns your simple robot into a smart obstacle-avoiding robot.

• Robot does not move — check battery charge and all wire connections
• Robot moves in circles — one motor may be wired in reverse, swap its wires
• Robot moves too fast — reduce the PWM speed value in your code
• Arduino resets when motors start — use separate power for motors and Arduino
• Sensor gives wrong readings — check wiring and ensure sensor is not blocked

Building a robot involves assembling a chassis, connecting motors through a driver, and writing Arduino code.

Start with a simple two-wheel robot that moves forward and turns.

Add sensors like ultrasonic to make your robot smarter.

Practice and experiment to improve your robot building skills.