Circuit Documentation

Summary

This circuit is designed to control multiple DC motors using an Arduino UNO and an L298N motor driver. The circuit also includes an HC-05 Bluetooth module for wireless communication and a power supply using 2x 18650 batteries. The Arduino UNO is programmed to receive commands via Bluetooth and control the motors accordingly.

Component List

1. Arduino UNO

   • Description: 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

2. DC Motor

   • Description: Standard DC motor.
   • Pins: pin 1, pin 2

3. L298N DC Motor Driver

   • Description: Dual H-Bridge motor driver.
   • Pins: OUT1, OUT2, 12V, GND, 5V, OUT3, OUT4, 5V-ENA-JMP-I, 5V-ENA-JMP-O, +5V-J1, +5V-J2, ENA, IN1, IN2, IN3, IN4, ENB

4. 2x 18650

   • Description: Battery pack with two 18650 batteries.
   • Pins: vcc, gnd

5. HC-05 Bluetooth Module

   • Description: Bluetooth module for wireless communication.
   • Pins: Key, VCC, GND, TXD, RXD, State

6. LED: Two Pin (white)

   • Description: Standard white LED.
   • Pins: cathode, anode

Wiring Details

Arduino UNO

• 5V connected to VCC of HC-05 Bluetooth Module
• GND connected to GND of HC-05 Bluetooth Module and GND of L298N DC Motor Driver
• Vin connected to 5V of L298N DC Motor Driver
• D13 connected to IN1 of L298N DC Motor Driver
• D12 connected to IN2 of L298N DC Motor Driver
• D11 connected to IN3 of L298N DC Motor Driver
• D10 connected to IN4 of L298N DC Motor Driver
• D1 connected to RXD of HC-05 Bluetooth Module
• D0 connected to TXD of HC-05 Bluetooth Module

DC Motor

• pin 1 of first motor connected to OUT4 of L298N DC Motor Driver
• pin 2 of first motor connected to OUT3 of L298N DC Motor Driver
• pin 1 of second motor connected to OUT4 of L298N DC Motor Driver
• pin 2 of second motor connected to OUT3 of L298N DC Motor Driver
• pin 1 of third motor connected to OUT2 of L298N DC Motor Driver
• pin 2 of third motor connected to OUT1 of L298N DC Motor Driver
• pin 1 of fourth motor connected to OUT2 of L298N DC Motor Driver
• pin 2 of fourth motor connected to OUT1 of L298N DC Motor Driver

L298N DC Motor Driver

• GND connected to GND of Arduino UNO and GND of 2x 18650 battery pack
• 5V connected to Vin of Arduino UNO
• 12V connected to vcc of 2x 18650 battery pack
• IN1 connected to D13 of Arduino UNO
• IN2 connected to D12 of Arduino UNO
• IN3 connected to D11 of Arduino UNO
• IN4 connected to D10 of Arduino UNO
• OUT1 connected to pin 2 of third and fourth DC motors
• OUT2 connected to pin 1 of third and fourth DC motors
• OUT3 connected to pin 2 of first and second DC motors
• OUT4 connected to pin 1 of first and second DC motors

2x 18650

• vcc connected to 12V of L298N DC Motor Driver
• gnd connected to GND of L298N DC Motor Driver and GND of Arduino UNO

HC-05 Bluetooth Module

• VCC connected to 5V of Arduino UNO
• GND connected to GND of Arduino UNO
• TXD connected to D0 of Arduino UNO
• RXD connected to D1 of Arduino UNO

Code Documentation

#define in1 5 //L298n Motor Driver pins.
#define in2 6
#define in3 10
#define in4 11
#define LED 13

int command; //Int to store app command state.
int Speed = 204; // 0 - 255.
int Speedsec;
int buttonState = 0;
int lastButtonState = 0;
int Turnradius = 0; //Set the radius of a turn, 0 - 255 Note:the robot will malfunction if this is higher than int Speed.
int brakeTime = 45;
int brkonoff = 1; //1 for the electronic braking system, 0 for normal.

void setup() {
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);
  pinMode(LED, OUTPUT); //Set the LED pin.
  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.
    switch (command) {
      case 'F':
        forward();
        break;
      case 'B':
        back();
        break;
      case 'L':
        left();
        break;
      case 'R':
        right();
        break;
      case 'G':
        forwardleft();
        break;
      case 'I':
        forwardright();
        break;
      case 'H':
        backleft();
        break;
      case 'J':
        backright();
        break;
      case '0':
        Speed = 100;
        break;
      case '1':
        Speed = 140;
        break;
      case '2':
        Speed = 153;
        break;
      case '3':
        Speed = 165;
        break;
      case '4':
        Speed = 178;
        break;
      case '5':
        Speed = 191;
        break;
      case '6':
        Speed = 204;
        break;
      case '7':
        Speed = 216;
        break;
      case '8':
        Speed = 229;
        break;
      case '9':
        Speed = 242;
        break;
      case 'q':
        Speed = 255;
        break;
    }
    Speedsec = Turnradius;
    if (brkonoff == 1) {
      brakeOn();
    } else {
      brakeOff();
    }
  }
}

void forward() {
  analogWrite(in1, Speed);
  analogWrite(in3, Speed);
}

void back() {
  analogWrite(in2, Speed);
  analogWrite(in4, Speed);
}

void left() {
  analogWrite(in3, Speed);
  analogWrite(in2, Speed);
}

void right() {
  analogWrite(in4, Speed);
  analogWrite(in1, Speed);
}

void forwardleft() {
  analogWrite(in1, Speedsec);
  analogWrite(in3, Speed);
}

void forwardright() {
  analogWrite(in1, Speed);
  analogWrite(in3, Speedsec);
}

void backright() {
  analogWrite(in2, Speed);
  analogWrite(in4, Speedsec);
}

void backleft() {
  analogWrite(in2, Speedsec);
  analogWrite(in4, Speed);
}

void Stop() {
  analogWrite(in1, 0);
  analogWrite(in2, 0);
  analogWrite(in3, 0);
  analogWrite(in4, 0);
}

void brakeOn() {
  //Here's the future use: an electronic braking system!
  // read the pushbutton input pin:
  buttonState = command;
  // compare the buttonState to its previous state
  if (buttonState != lastButtonState) {
    // if the state has changed, increment the counter
    if (buttonState == 'S') {
      if (lastButtonState != buttonState) {
        digitalWrite(in1, HIGH);
        digitalWrite(in2, HIGH);
        digitalWrite(in3, HIGH);
        digitalWrite(in4, HIGH);
        delay(brakeTime);
        Stop();
      }
    }