Circuit Documentation

Summary

This circuit is designed to control a car via Bluetooth using an Arduino UNO microcontroller. The Arduino UNO interfaces with an L298N DC motor driver to control the direction and speed of the motors attached to the wheels. The circuit also includes two LM393 modules, which could be used for sensing applications, and a power supply consisting of a 2 x AA battery mount with a rocker switch for power control.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• It has 14 digital input/output pins, 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header, and a reset button.

L298N DC Motor Driver

• A high-power motor driver module capable of driving up to two DC motors.
• It has inputs for motor control signals and power supply connections.

Motors and Wheels (x2)

• DC motors connected to wheels for providing motion to the car.

LM393 Modules (x2)

• Voltage comparator modules that can be used for various sensing applications.

2 x AA Battery Mount

• A battery holder for two AA batteries, providing power to the circuit.

Rocker Switch

• A switch to control the power supply to the circuit.

Wiring Details

Arduino UNO

• 5V connected to the VCC of both LM393 modules.
• GND connected to the GND of both LM393 modules.
• D11 connected to ENA on the L298N motor driver.
• D10 connected to IN1 on the L298N motor driver.
• D9 connected to IN2 on the L298N motor driver.
• D6 connected to IN3 on the L298N motor driver.
• D5 connected to IN4 on the L298N motor driver.
• D3 connected to ENB on the L298N motor driver.
• A0 connected to A0 on the first LM393 module.
• A1 connected to A0 on the second LM393 module.
• D4 connected to D0 on the second LM393 module.
• D2 connected to D0 on the first LM393 module.

L298N DC Motor Driver

• OUT1 and OUT2 connected to the first motor and wheels.
• OUT3 and OUT4 connected to the second motor and wheels.
• 12V connected to the 2 pin on the Rocker Switch.
• GND connected to the - pin on the 2 x AA Battery Mount.

Motors and Wheels

• Each motor has two connections, vcc and GND, which are connected to the corresponding OUT pins on the L298N motor driver.

LM393 Modules

• VCC connected to 5V on the Arduino UNO.
• GND connected to GND on the Arduino UNO.
• A0 connected to analog pins A0 and A1 on the Arduino UNO for the first and second modules, respectively.
• D0 connected to digital pins D2 and D4 on the Arduino UNO for the first and second modules, respectively.

2 x AA Battery Mount

• + connected to the 1 pin on the Rocker Switch.
• - connected to GND on the L298N motor driver.

Rocker Switch

• 1 connected to the + pin on the 2 x AA Battery Mount.
• 2 connected to the 12V pin on the L298N motor driver.

Documented Code

//Arduino Bluetooth Controlled Car
//Before uploading the code you have to install the necessary library
//AFMotor Library https://learn.adafruit.com/adafruit-motor-shield/library-install
//Now You Can Upload the Code without any problem but make sure the bt module isn't connected with Arduino while uploading code

#include <AFMotor.h>

//initial motors pin
AF_DCMotor motor1(1, MOTOR12_1KHZ); 
AF_DCMotor motor2(2, MOTOR12_1KHZ); 
AF_DCMotor motor3(3, MOTOR34_1KHZ);
AF_DCMotor motor4(4, MOTOR34_1KHZ);

char command; 

void setup() 
{       
  Serial.begin(9600);  //Set the baud rate to your Bluetooth module.
}

void loop(){
  if(Serial.available() > 0){ 
    command = Serial.read(); 
    Stop(); //initialize with motors stopped
    //Change pin mode only if new command is different from previous.
    switch(command){
    case 'F':  
      forward();
      break;
    case 'B':  
       back();
      break;
    case 'L':  
      left();
      break;
    case 'R':
      right();
      break;
    }
  } 
}

void forward()
{
  motor1.setSpeed(255); //Define maximum velocity
  motor1.run(FORWARD); //rotate the motor clockwise
  motor2.setSpeed(255); //Define maximum velocity
  motor2.run(FORWARD); //rotate the motor clockwise
  motor3.setSpeed(255);//Define maximum velocity
  motor3.run(FORWARD); //rotate the motor clockwise
  motor4.setSpeed(255);//Define maximum velocity
  motor4.run(FORWARD); //rotate the motor clockwise
}

void back()
{
  motor1.setSpeed(255); //Define maximum velocity
  motor1.run(BACKWARD); //rotate the motor anti-clockwise
  motor2.setSpeed(255); //Define maximum velocity
  motor2.run(BACKWARD); //rotate the motor anti-clockwise
  motor3.setSpeed(255); //Define maximum velocity
  motor3.run(BACKWARD); //rotate the motor anti-clockwise
  motor4.setSpeed(255); //Define maximum velocity
  motor4.run(BACKWARD); //rotate the motor anti-clockwise
}

void left()
{
  motor1.setSpeed(255); //Define maximum velocity
  motor1.run(BACKWARD); //rotate the motor anti-clockwise
  motor2.setSpeed(255); //Define maximum velocity
  motor2.run(BACKWARD); //rotate the motor anti-clockwise
  motor3.setSpeed(255); //Define maximum velocity
  motor3.run(FORWARD);  //rotate the motor clockwise
  motor4.setSpeed(255); //Define maximum velocity
  motor4.run(FORWARD);  //rotate the motor clockwise
}

void right()
{
  motor1.setSpeed(255); //Define maximum velocity
  motor1.run(FORWARD); //rotate the motor clockwise
  motor2.setSpeed(255); //Define maximum velocity
  motor2.run(FORWARD); //rotate the motor clockwise
  motor3.setSpeed(255); //Define maximum velocity
  motor3.run(BACKWARD); //rotate the motor anti-clockwise
  motor4.setSpeed(255); //Define maximum velocity
  motor4.run(BACKWARD); //rotate the motor anti-clockwise
} 

void Stop()
{
  motor1.setSpeed(0); //Define minimum velocity
  motor1.run(RELEASE); //stop the motor when release the button
  motor2.setSpeed(0); //Define minimum velocity
  motor2.run(RELEASE); //stop the motor when release the button
  motor3.setSpeed(0); //Define minimum velocity
  motor3.run(RELEASE); //stop the motor when release the button
  motor4.setSpeed(0); //Define minimum velocity
  motor4.run(RELEASE); //stop the motor when release the button
}

This code is designed to receive commands via Bluetooth and control the motors accordingly to move the car forward, backward, left, or right. The AFMotor library is used to interface with the motor driver, and the speed of each motor is set to its maximum value when moving. The Stop function stops all motors by setting their speed to zero and releasing them.