Accident Avoiding Car Project

About the Project

The Accident Avoiding Car is an innovative project designed to enhance road safety through autonomous obstacle detection and avoidance. Using advanced sensor technology, this system can detect obstacles in real-time and take preventive actions to avoid collisions.

This project uses an Arduino UNO microcontroller combined with an ultrasonic sensor to measure the distance to obstacles. When an object is detected within 20cm, the system automatically stops the car by activating a relay module that controls the motors.

Arduino Based

Ultrasonic Detection

Real-time obstacle distance measurement

Auto Safety

Automatic stop when obstacle detected

Hardware Components Required

All the components needed to build this project

Arduino UNO

Description: The main microcontroller board that runs the code and controls all other components. It processes sensor data and controls the relay.

Specifications:

Microcontroller: ATmega328P
Operating Voltage: 5V
Digital I/O Pins: 14
Used Pins: 7, 12, 13

Quantity: 1 Buy Now

Ultrasonic Sensor (HC-SR04)

Description: Measures distance to obstacles using ultrasonic sound waves. Sends and receives signals to calculate distance accurately.

Specifications:

Range: 2cm to 400cm
Operating Voltage: 5V
Trigger Pin: Pin 13
Echo Pin: Pin 12
Detection Angle: 15°

Quantity: 1 Buy Now

Gear Motor (with Driver)

Description: High-torque DC motors that drive the car wheels. Provides sufficient power for movement and can be controlled via the relay.

Specifications:

Voltage: 6V - 12V DC
RPM: 100-300
Torque: High
Shaft: Compatible with wheels

Quantity: 2 Buy Now

Wheels

Description: Durable plastic or rubber wheels that attach to the gear motors. Provides smooth movement and traction.

Specifications:

Diameter: 65mm - 70mm
Material: Rubber/Plastic
Mounting: Compatible with motor shaft
Type: 2 powered + 2 free/caster

Quantity: 4

Relay Module

Description: An electronically controlled switch that controls the motor power. Active LOW relay - HIGH signal stops the car, LOW signal allows movement.

Specifications:

Type: Single Channel Relay
Operating Voltage: 5V
Control Pin: Pin 7
Load: Up to 10A
Trigger: Active LOW

Quantity: 1 Buy Now

Jumper Wires

Description: Male-to-male, male-to-female, and female-to-female wires for making connections between components.

Specifications:

Length: 20cm standard
Types: M-M, M-F, F-F
Colors: Multiple for easy tracking
Rating: 24 AWG

Quantity: 10-15 wires Buy Now

Power Switch

Description: ON/OFF toggle switch to control the main power supply to the entire circuit.

Specifications:

Type: SPST Toggle Switch
Rating: 3A 250V
Mounting: Panel mount
Operation: ON/OFF

Quantity: 1

9V Battery

Description: Portable power source - one for Arduino and one for motors. Provides independent power supply for stable operation.

Specifications:

Voltage: 9V DC
Capacity: 500-600mAh
Type: PP3 (Alkaline/Rechargeable)
Usage: 1 for Arduino, 1 for Motors

Quantity: 2

Arduino Code

Upload this code to your Arduino UNO using the Arduino IDE

How the Code Works:

1. Pin Setup:

Pin 13 (Trigger) and Pin 12 (Echo) for ultrasonic sensor. Pin 7 controls the relay module.

2. Distance Measurement:

Sends ultrasonic pulse and measures echo time. Converts time to distance in centimeters.

3. Decision Logic:

If obstacle detected within 20cm, relay turns HIGH (stops car). Otherwise, relay stays LOW (car moves).

4. Active LOW Relay:

This relay works in reverse - LOW = Motors ON (moving), HIGH = Motors OFF (stopped).

accident_avoiding_car.ino

#define trigPin 13
#define echoPin 12
#define relayPin 7

long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(relayPin, OUTPUT);

  Serial.begin(9600);

  digitalWrite(relayPin, LOW);  // LOW = Car Moving (Active LOW Relay)
}

void loop() {

  // Send ultrasonic pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Measure echo time
  duration = pulseIn(echoPin, HIGH);

  // Convert to distance (cm)
  distance = duration * 0.034 / 2;

  Serial.print("Distance: ");
  Serial.println(distance);

  if (distance > 0 && distance <= 20) {
    
    digitalWrite(relayPin, HIGH);  // STOP (because relay active LOW)
    Serial.println("STOP");

  } else {

    digitalWrite(relayPin, LOW);   // MOVE
    Serial.println("MOVING");
  }

  delay(200);
}

Upload Instructions:

Connect your Arduino UNO to your computer via USB cable
Open Arduino IDE software
Copy the code above and paste it in the Arduino IDE
Select Tools → Board → Arduino UNO
Select Tools → Port → COM X (your Arduino's port)
Click the Upload button (→ icon)
Wait for "Done uploading" message
Open Tools → Serial Monitor to see distance readings

Important Circuit Notes:

Connect ultrasonic sensor VCC to Arduino 5V, GND to GND
Trigger pin to Arduino Pin 13, Echo pin to Arduino Pin 12
Relay signal pin to Arduino Pin 7, VCC to 5V, GND to GND
Connect motors through relay (COM and NO terminals)
Use separate power supply for motors (9V battery)
Ensure common ground between Arduino and motor power supply

About the Project

Arduino Based

Ultrasonic Detection

Auto Safety

Hardware Components Required

Arduino UNO

Ultrasonic Sensor (HC-SR04)

Gear Motor (with Driver)

Wheels

Relay Module

Jumper Wires

Power Switch

9V Battery

Arduino Code

How the Code Works:

Upload Instructions:

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