Circuit Documentation

Summary

This circuit is designed to control a set of DC motors using an Arduino Uno R3 microcontroller and an L298N DC motor driver. The circuit includes a Bluetooth module (HC-05) for wireless communication and an LED indicator. The Arduino Uno R3 is programmed to interpret serial commands to control the motion of the motors (forward, reverse, left, right, stop) and to toggle the LED state. The motors are powered by a 4 x AAA battery mount, and the Arduino is responsible for driving the motors through the L298N motor driver.

Component List

Arduino Uno R3

• Microcontroller board based on the ATmega328P
• Features digital I/O pins, analog input pins, and various power options

L298N DC Motor Driver

• A dual H-bridge motor driver capable of driving two DC motors or one stepper motor
• Provides an external power supply option for motors

DC Motors (4x)

• Standard DC motors for driving mechanical loads
• Each motor has two pins: one for power and one for ground

HC-05 Bluetooth Module

• A wireless communication module that allows for serial communication via Bluetooth
• Features pins for power, ground, transmit (TX), receive (RX), and state

LED: Two Pin (red)

• A simple red LED with an anode and cathode for indication purposes

4 x AAA Battery Mount

• A battery holder for four AAA batteries
• Provides power to the circuit with positive and negative terminals

Wiring Details

Arduino Uno R3

• 3.3V connected to the anode of the red LED
• 5V connected to the VCC of the HC-05 Bluetooth module
• GND connected to the ground of the battery mount, L298N motor driver, and HC-05 Bluetooth module
• VIN connected to the 5V input of the L298N motor driver
• Digital pins 13, 12, 11, and 10 connected to the IN1, IN2, IN3, and IN4 of the L298N motor driver respectively
• Digital pin 9 connected to the cathode of the red LED
• Digital pins 1 and 0 (TX/RX) connected to the RXD and TXD of the HC-05 Bluetooth module

L298N DC Motor Driver

• OUT1 and OUT2 connected to the DC motors (motor A)
• OUT3 and OUT4 connected to the DC motors (motor B)
• 12V connected to the positive terminal of the battery mount
• GND connected to the ground of the Arduino Uno R3

DC Motors

• Each motor has one pin connected to an OUT pin on the L298N motor driver and the other pin to another OUT pin for the opposite direction

HC-05 Bluetooth Module

• VCC connected to the 5V of the Arduino Uno R3
• GND connected to the GND of the Arduino Uno R3
• TXD connected to the RX (pin 0) of the Arduino Uno R3
• RXD connected to the TX (pin 1) of the Arduino Uno R3

LED: Two Pin (red)

• Anode connected to the 3.3V of the Arduino Uno R3
• Cathode connected to the digital pin 9 of the Arduino Uno R3

4 x AAA Battery Mount

• + connected to the 12V of the L298N motor driver
• - connected to the GND of the Arduino Uno R3

Documented Code

char t;

void setup() {
  pinMode(13, OUTPUT);   // left motors forward
  pinMode(12, OUTPUT);   // left motors reverse
  pinMode(11, OUTPUT);   // right motors forward
  pinMode(10, OUTPUT);   // right motors reverse
  pinMode(9, OUTPUT);    // LED
  Serial.begin(9600);
}

void loop() {
  if (Serial.available()) {
    t = Serial.read();
    Serial.println(t);
  }

  if (t == 'F') {            // move forward (all motors rotate in forward direction)
    digitalWrite(13, HIGH);
    digitalWrite(11, HIGH);
  } else if (t == 'B') {     // move reverse (all motors rotate in reverse direction)
    digitalWrite(12, HIGH);
    digitalWrite(10, HIGH);
  } else if (t == 'L') {     // turn right (left side motors rotate in forward direction, right side motors don't rotate)
    digitalWrite(11, HIGH);
  } else if (t == 'R') {     // turn left (right side motors rotate in forward direction, left side motors don't rotate)
    digitalWrite(13, HIGH);
  } else if (t == 'W') {     // turn LED on
    digitalWrite(9, HIGH);
  } else if (t == 'w') {     // turn LED off
    digitalWrite(9, LOW);
  } else if (t == 'S') {     // STOP (all motors stop)
    digitalWrite(13, LOW);
    digitalWrite(12, LOW);
    digitalWrite(11, LOW);
    digitalWrite(10, LOW);
  }
  delay(100);
}

This code is designed to run on the Arduino Uno R3. It sets up the necessary pins as outputs and initializes serial communication. The loop function reads a character from the serial port and controls the motors and LED based on the received command.