दो IR सेंसर वाला लाइन फ़ॉलोअर रोबोट (Arduino Uno)

// Line follower robot — Arduino Uno + 2× TCRT5000 IR modules + L298N + 2 DC gear motors.
// The two sensors straddle a black line: the side that sees black steers back towards it.
// Left TCRT5000 DO → D2, right TCRT5000 DO → D3.
// L298N ENA → D5, IN1 → A0, IN2 → A1, ENB → D6, IN3 → A2, IN4 → A3.
constexpr uint8_t LEFT_SENSOR = 2, RIGHT_SENSOR = 3;
constexpr uint8_t ENA = 5, IN1 = A0, IN2 = A1;   // left motor
constexpr uint8_t ENB = 6, IN3 = A2, IN4 = A3;   // right motor
// Most TCRT5000 modules pull DO LOW over a white (reflective) surface and HIGH over black.
constexpr bool LINE_IS_HIGH = true;
constexpr uint8_t FAST = 160, TURN = 140;        // 0–255; the L298N loses ~2 V, so don't go too low

int lastTurn = 0;                                // -1 = last saw the line on the left, +1 = right

void motor(uint8_t en, uint8_t a, uint8_t b, int speed) {
  digitalWrite(a, speed >= 0 ? HIGH : LOW);
  digitalWrite(b, speed >= 0 ? LOW : HIGH);
  analogWrite(en, abs(speed));
}

void drive(int left, int right) {
  motor(ENA, IN1, IN2, left);
  motor(ENB, IN3, IN4, right);
}

bool onLine(uint8_t pin) {
  return (digitalRead(pin) == HIGH) == LINE_IS_HIGH;
}

void setup() {
  const uint8_t outputs[] = {ENA, IN1, IN2, ENB, IN3, IN4};
  for (uint8_t p : outputs) pinMode(p, OUTPUT);
  pinMode(LEFT_SENSOR, INPUT);
  pinMode(RIGHT_SENSOR, INPUT);
  drive(0, 0);
  delay(2000);                                   // time to put it down on the track
}

void loop() {
  bool left = onLine(LEFT_SENSOR), right = onLine(RIGHT_SENSOR);
  if (left && !right) {                          // line drifted left → pivot left
    drive(-TURN, TURN);
    lastTurn = -1;
  } else if (right && !left) {                   // line drifted right → pivot right
    drive(TURN, -TURN);
    lastTurn = 1;
  } else if (!left && !right) {                  // line between the sensors → straight on
    drive(FAST, FAST);
  } else {                                       // both on black: a junction or a wide bend —
    drive(lastTurn * TURN, -lastTurn * TURN);    // keep turning the way we last turned
  }
}

// Line follower robot — Arduino Uno + 2× TCRT5000 IR modules + L298N + 2 DC gear motors.
// The two sensors straddle a black line: the side that sees black steers back towards it.
// Left TCRT5000 DO → D2, right TCRT5000 DO → D3.
// L298N ENA → D5, IN1 → A0, IN2 → A1, ENB → D6, IN3 → A2, IN4 → A3.
constexpr uint8_t LEFT_SENSOR = 2, RIGHT_SENSOR = 3;
constexpr uint8_t ENA = 5, IN1 = A0, IN2 = A1;   // left motor
constexpr uint8_t ENB = 6, IN3 = A2, IN4 = A3;   // right motor
// Most TCRT5000 modules pull DO LOW over a white (reflective) surface and HIGH over black.
constexpr bool LINE_IS_HIGH = true;
constexpr uint8_t FAST = 160, TURN = 140;        // 0–255; the L298N loses ~2 V, so don't go too low

int lastTurn = 0;                                // -1 = last saw the line on the left, +1 = right

void motor(uint8_t en, uint8_t a, uint8_t b, int speed) {
  digitalWrite(a, speed >= 0 ? HIGH : LOW);
  digitalWrite(b, speed >= 0 ? LOW : HIGH);
  analogWrite(en, abs(speed));
}

void drive(int left, int right) {
  motor(ENA, IN1, IN2, left);
  motor(ENB, IN3, IN4, right);
}

bool onLine(uint8_t pin) {
  return (digitalRead(pin) == HIGH) == LINE_IS_HIGH;
}

void setup() {
  const uint8_t outputs[] = {ENA, IN1, IN2, ENB, IN3, IN4};
  for (uint8_t p : outputs) pinMode(p, OUTPUT);
  pinMode(LEFT_SENSOR, INPUT);
  pinMode(RIGHT_SENSOR, INPUT);
  drive(0, 0);
  delay(2000);                                   // time to put it down on the track
}

void loop() {
  bool left = onLine(LEFT_SENSOR), right = onLine(RIGHT_SENSOR);
  if (left && !right) {                          // line drifted left → pivot left
    drive(-TURN, TURN);
    lastTurn = -1;
  } else if (right && !left) {                   // line drifted right → pivot right
    drive(TURN, -TURN);
    lastTurn = 1;
  } else if (!left && !right) {                  // line between the sensors → straight on
    drive(FAST, FAST);
  } else {                                       // both on black: a junction or a wide bend —
    drive(lastTurn * TURN, -lastTurn * TURN);    // keep turning the way we last turned
  }
}