Project Documentation

Arduino UNO Bluetooth-Controlled Robotic Car with Ultrasonic Distance Sensing

Circuit Documentation

Summary

This circuit is designed to control a set of DC motors using an Arduino UNO and an L293D motor driver shield. The circuit also includes an HC-SR04 ultrasonic distance sensor, a sound sensor, and an HC-05 Bluetooth module for remote control. The power is supplied by a 18650 Li-Ion battery.

Component List

Arduino UNO
- Description: A microcontroller board based on the ATmega328P.
- Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0
L293D Driver Shield
- Description: A motor driver shield capable of driving four DC motors.
- Pins: 5v, GND, A0, A1, A2, A3, A4, A5, M+, M2, M2, M1, M3, M4, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, gnd, Aref, ser1, Servo2, +, -, 9v
18650 Li-Ion Battery
- Description: A rechargeable lithium-ion battery.
- Pins: Positive, Negative
DC Motor (4 units)
- Description: A simple DC motor.
- Pins: pin 1, pin 2
HC-SR04 Ultrasonic Distance Sensor
- Description: A sensor used to measure distance using ultrasonic waves.
- Pins: VCC, TRIG, ECHO, GND
Sound Sensor
- Description: A sensor used to detect sound levels.
- Pins: VCC, GND, DO, AO
HC-05 Bluetooth Module
- Description: A Bluetooth module used for wireless communication.
- Pins: Key, VCC, GND, TXD, RXD, State

Wiring Details

Arduino UNO

AREF connected to Aref of L293D Driver Shield
GND connected to gnd of L293D Driver Shield
D13 connected to 12 of L293D Driver Shield
D12 connected to 12 of L293D Driver Shield
D11 connected to 11 of L293D Driver Shield
D10 connected to 10 of L293D Driver Shield
D9 connected to 9 of L293D Driver Shield
D8 connected to 8 of L293D Driver Shield
D7 connected to 7 of L293D Driver Shield
D6 connected to 6 of L293D Driver Shield
D5 connected to 5 of L293D Driver Shield
D4 connected to 4 of L293D Driver Shield
D3 connected to 3 of L293D Driver Shield
D2 connected to 2 of L293D Driver Shield
D1 connected to 1 of L293D Driver Shield
D0 connected to 0 of L293D Driver Shield

L293D Driver Shield

5v connected to 5v of HC-SR04 Ultrasonic Distance Sensor
GND connected to GND of HC-SR04 Ultrasonic Distance Sensor
A0 connected to TRIG of HC-SR04 Ultrasonic Distance Sensor
A1 connected to ECHO of HC-SR04 Ultrasonic Distance Sensor
M+ connected to Positive of 18650 Li-Ion Battery
GND connected to Negative of 18650 Li-Ion Battery
M2 connected to pin 1 of DC Motor
M2 connected to pin 2 of DC Motor
M1 connected to pin 1 of DC Motor
M1 connected to pin 2 of DC Motor
M3 connected to pin 1 of DC Motor
M3 connected to pin 2 of DC Motor
M4 connected to pin 1 of DC Motor
M4 connected to pin 2 of DC Motor
ser1 connected to RXD of HC-05 Bluetooth Module
Servo2 connected to TXD of HC-05 Bluetooth Module
+ connected to VCC of HC-05 Bluetooth Module
- connected to GND of HC-05 Bluetooth Module

HC-SR04 Ultrasonic Distance Sensor

VCC connected to 5v of L293D Driver Shield
GND connected to GND of L293D Driver Shield
TRIG connected to A0 of L293D Driver Shield
ECHO connected to A1 of L293D Driver Shield

18650 Li-Ion Battery

Positive connected to M+ of L293D Driver Shield
Negative connected to GND of L293D Driver Shield

DC Motor (4 units)

pin 1 connected to M2 of L293D Driver Shield
pin 2 connected to M2 of L293D Driver Shield
pin 1 connected to M1 of L293D Driver Shield
pin 2 connected to M1 of L293D Driver Shield
pin 1 connected to M3 of L293D Driver Shield
pin 2 connected to M3 of L293D Driver Shield
pin 1 connected to M4 of L293D Driver Shield
pin 2 connected to M4 of L293D Driver Shield

HC-05 Bluetooth Module

RXD connected to ser1 of L293D Driver Shield
TXD connected to Servo2 of L293D Driver Shield
VCC connected to + of L293D Driver Shield
GND connected to - of L293D Driver Shield

Documented Code

#include <AFMotor.h>
#include <SoftwareSerial.h>

SoftwareSerial bluetoothSerial(9, 10); // RX, TX

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

void loop() {
  if (bluetoothSerial.available() > 0) {
    command = bluetoothSerial.read();

    Stop(); //initialize with motors stoped
    
    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(FORWARD); //rotate the motor clockwise
  motor3.setSpeed(255); //Define maximum velocity
  motor3.run