How To Make A DIY Arduino Obstacle Avoiding Car At Home?

Alright — let’s walk through building a DIY Arduino Obstacle Avoiding Car step-by-step.
I’ll give you the parts list, wiring diagram explanation, Arduino code, and how it works so you can make it at home.

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1. Parts You’ll Need

Component	Quantity	Purpose
Arduino UNO (or Nano)	1	Main controller
Ultrasonic Sensor (HC-SR04)	1	Distance measurement
Servo Motor (SG90)	1	Rotates the sensor for scanning
L298N Motor Driver Module	1	Controls DC motors
DC Motors with Wheels	2–4	Movement
Caster wheel	1	Support
Chassis (DIY or ready-made)	1	Body frame
Jumper wires	—	Connections
Battery pack (6V–12V)	1	Power supply

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2. Wiring Connections

Ultrasonic Sensor (HC-SR04) → Arduino

• VCC → 5V
• GND → GND
• TRIG → D9
• ECHO → D10

Servo Motor → Arduino

• Signal → D11
• VCC → 5V
• GND → GND

L298N Motor Driver → Arduino

• IN1 → D2
• IN2 → D3
• IN3 → D4
• IN4 → D5
• ENA → 5V (or PWM pin if speed control)
• ENB → 5V
• Motor A → Left motor
• Motor B → Right motor
• L298N VCC → Battery + (6–12V)
• L298N GND → Battery – & Arduino GND

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3. Arduino Code

#include <Servo.h>

Servo myServo;
#define trigPin 9
#define echoPin 10
#define servoPin 11

#define IN1 2
#define IN2 3
#define IN3 4
#define IN4 5

long distance;
long duration;

void setup() {
  Serial.begin(9600);
  myServo.attach(servoPin);
  
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);
}

long getDistance() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  return duration * 0.034 / 2; // Convert to cm
}

void forward() {
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
}

void backward() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH);
}

void left() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
  digitalWrite(IN3, HIGH);
  digitalWrite(IN4, LOW);
}

void right() {
  digitalWrite(IN1, HIGH);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, HIGH);
}

void stopCar() {
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, LOW);
  digitalWrite(IN3, LOW);
  digitalWrite(IN4, LOW);
}

void loop() {
  myServo.write(90); // Forward facing
  delay(200);
  distance = getDistance();
  
  if (distance > 20) {
    forward();
  } else {
    stopCar();
    delay(300);
    
    myServo.write(0); // Scan left
    delay(500);
    long leftDist = getDistance();
    
    myServo.write(180); // Scan right
    delay(500);
    long rightDist = getDistance();
    
    myServo.write(90); // Reset center
    
    if (leftDist > rightDist) {
      left();
      delay(500);
    } else {
      right();
      delay(500);
    }
  }
}

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4. How It Works

1. The servo motor rotates the ultrasonic sensor to scan front, left, and right.
2. The Arduino measures distances using the HC-SR04 sensor.
3. If the path is clear, the car moves forward.
4. If there’s an obstacle, it stops, looks left and right, then chooses the side with more space.
5. Motor driver powers the DC motors based on Arduino signals.

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5. Tips

• Use a rechargeable Li-ion battery for better performance.
• Reduce servo movement delays for faster reaction.
• Add LEDs to indicate movement direction for fun.

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