Bluetooth RC Jeep – Arduino Code

#include <SoftwareSerial.h>
#include <Servo.h>

// ==================================
// Bluetooth HC-05
// ==================================
SoftwareSerial BT(2, 7);  // RX, TX

// ==================================
// MX1508 Motor Driver
// ==================================
#define IN1 5
#define IN2 6
#define IN3 11
#define IN4 3

// ==================================
// Servo Motor SG90
// ==================================
#define SERVO_PIN 4

Servo steering;

// ==================================
// Motor Speed
// ==================================
int motorSpeed = 200;

// ==================================
// Steering Angles - CORRECTED
// ==================================
const int CENTER = 90;
const int LEFT   = 120;
const int RIGHT  = 60;

// ==================================
// Safety Timeout
// ==================================
const unsigned long TIMEOUT = 150;

unsigned long lastCommandTime = 0;

bool moving = false;
char currentDirection = 'S';

// ==================================
// STOP MOTORS
// ==================================
void stopMotors() {
  analogWrite(IN1, 0);
  analogWrite(IN2, 0);

  analogWrite(IN3, 0);
  analogWrite(IN4, 0);

  moving = false;
  currentDirection = 'S';
}

// ==================================
// FORWARD
// ==================================
void forward() {
  analogWrite(IN1, motorSpeed);
  analogWrite(IN2, 0);

  analogWrite(IN3, motorSpeed);
  analogWrite(IN4, 0);

  moving = true;
  currentDirection = 'F';
}

// ==================================
// BACKWARD
// ==================================
void backward() {
  analogWrite(IN1, 0);
  analogWrite(IN2, motorSpeed);

  analogWrite(IN3, 0);
  analogWrite(IN4, motorSpeed);

  moving = true;
  currentDirection = 'B';
}

// ==================================
// SETUP
// ==================================
void setup() {
  Serial.begin(9600);
  BT.begin(9600);

  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  pinMode(IN3, OUTPUT);
  pinMode(IN4, OUTPUT);

  stopMotors();

  steering.attach(SERVO_PIN);
  steering.write(CENTER);

  lastCommandTime = millis();

  Serial.println("Bluetooth RC Car Ready");
}

// ==================================
// MAIN LOOP
// ==================================
void loop() {

  while (BT.available()) {

    char command = BT.read();

    if (command == '\n' || command == '\r') {
      continue;
    }

    Serial.print("Received: ");
    Serial.println(command);

    switch (command) {

      // FORWARD
      case 'F':
        steering.write(CENTER);
        forward();
        lastCommandTime = millis();
        break;

      // BACKWARD
      case 'B':
        steering.write(CENTER);
        backward();
        lastCommandTime = millis();
        break;

      // LEFT - CORRECTED
      case 'L':
        steering.write(LEFT);
        forward();
        lastCommandTime = millis();
        break;

      // RIGHT - CORRECTED
      case 'R':
        steering.write(RIGHT);
        forward();
        lastCommandTime = millis();
        break;

      // STOP
      case 'S':
        stopMotors();
        steering.write(CENTER);
        break;

      // CENTER STEERING
      case 'C':
        steering.write(CENTER);
        break;

      // INCREASE SPEED
      case '+':
        motorSpeed = min(255, motorSpeed + 15);

        if (moving) {
          if (currentDirection == 'B') {
            backward();
          } else {
            forward();
          }
        }
        break;

      // DECREASE SPEED
      case '-':
        motorSpeed = max(80, motorSpeed - 15);

        if (moving) {
          if (currentDirection == 'B') {
            backward();
          } else {
            forward();
          }
        }
        break;
    }
  }

  // ==================================
  // AUTOMATIC STOP
  // ==================================
  if (moving &&
      millis() - lastCommandTime > TIMEOUT) {

    stopMotors();
    steering.write(CENTER);
  }
}