Published February 24, 2023 © GPL3+

Sound Controlled Car using Arduino and NPN Transistor

This project shows how to build a car that can be controlled by sound.

BeginnerShowcase (no instructions)1 hour800

Sound Controlled Car using Arduino and NPN Transistor

Things used in this project

Hardware components

Arduino UNO

General Purpose Transistor NPN

Microphone, Omnidirectional

Through Hole Resistor, 3.3 kohm

Resistor 220 ohm

660 Ω Resistor

LED (generic)

L298N Motor Driver Module

DC Motor, 12 V

Jumper wires (generic)

Software apps and online services

Arduino IDE

Story

This project shows how to build a car that is controlled by sound.

The project demonstrates how to assemble these components (through a schematic and a circuit diagram) and program the Arduino board to recognize sounds and use it to control the movement of the car.

By following the steps mentioned, you will have a fully functional car that can be controlled by clapping, whistling, or making other sounds. This exciting project is a great way to learn about electronics, programming, and robotics.

Watch this video for details:

Code

Code

//Initialize the variables
uint8_t rightMotorForward = 5;
uint8_t rightMotorBackward = 6;
uint8_t leftMotorForward = 10;
uint8_t leftMotorBackward = 11;
uint8_t sensor = A0;
byte clapCount = 0;
byte prevClapCount = clapCount;

void setup() {

  //set the modes of the pins as input/output
  for (int i = 9; i < 13; i = i + 1) {
    pinMode(i, OUTPUT);
  }

  pinMode(sensor, INPUT);
  pinMode(A1, OUTPUT);
  pinMode(A2, OUTPUT);

  //set the speed of the motors
  analogWrite(A1, 128);
  analogWrite(A2, 128);

  //start serial communication
  Serial.begin(9600);

}

void loop() {

  //if a sound is detected...
  if (analogRead(sensor) < 50) {
    clapCount = (clapCount < 7) ? ++clapCount : 0; //updates the variable 'clapCount'
    delay(1000);
  }

  //if the data stored in 'clapCount' changes...
  if (prevClapCount != clapCount) {

    //moves the car accordingly
    switch (clapCount) {

      case 0:
        stop();
        break;
      
      case 1:
        front();
        break;

      case 2:
        stop();
        break;

      case 3:
        back();
        break;

      case 4:
        stop();
        break;

      case 5:
        left();
        break;

      case 6:
        stop();
        break;

      case 7:
        right();
        break;

    }

    prevClapCount = clapCount;
    
  }

}

//function to move the car forward
void front() {

  analogWrite(leftMotorForward, 128);
  analogWrite(rightMotorForward, 128);
  analogWrite(leftMotorBackward, 0);
  analogWrite(rightMotorBackward, 0);
  Serial.println("Front");

}

//function to move the car backwards
void back() {

  analogWrite(leftMotorForward, 0);
  analogWrite(rightMotorForward, 0);
  analogWrite(leftMotorBackward, 128);
  analogWrite(rightMotorBackward, 128);
  Serial.println("Back");

}

//function to turn the car left
void left() {

  analogWrite(leftMotorForward, 0);
  analogWrite(rightMotorForward, 128);
  analogWrite(leftMotorBackward, 0);
  analogWrite(rightMotorBackward, 0);
  Serial.println("Left");

}

//function to turn the car right
void right() {

  analogWrite(leftMotorForward, 128);
  analogWrite(rightMotorForward, 0);
  analogWrite(leftMotorBackward, 0);
  analogWrite(rightMotorBackward, 0);
  Serial.println("Right");

}

//function to stop the car
void stop() {

  digitalWrite(leftMotorForward, LOW);
  digitalWrite(rightMotorForward, LOW);
  digitalWrite(leftMotorBackward, LOW);
  digitalWrite(rightMotorBackward, LOW);
  Serial.println("Stop");

}