/*
 * ============================================================
 *  IR Obstacle Sensor (ADIY with Potentiometer) — Sample Sketch
 *  Tishvi Electronics | guide.tishvi.com
 * ============================================================
 *  Wiring:
 *    IR Sensor VCC → Arduino 5V
 *    IR Sensor GND → Arduino GND
 *    IR Sensor OUT → Arduino Pin 7
 *
 *  What this sketch does:
 *    1. Reads the digital OUT pin of the IR sensor
 *    2. OUT = LOW  → Object detected (obstacle in range)
 *    3. OUT = HIGH → No object detected (path is clear)
 *    4. Prints status to Serial Monitor
 *    5. Blinks the built-in LED (pin 13) when an object is detected
 *
 *  Detection range: 2–10 cm (adjust the blue potentiometer on the sensor)
 *  No external libraries needed.
 * ============================================================
 */

// ── Pin Definitions ──────────────────────────────────────────
const int IR_OUT_PIN   = 7;   // IR sensor OUT → Arduino digital pin 7
const int LED_PIN      = 13;  // Built-in LED for visual feedback

// ── Variables ────────────────────────────────────────────────
bool lastState = HIGH;        // Track previous sensor state to detect changes

void setup() {
  pinMode(IR_OUT_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
  Serial.begin(9600);
  Serial.println("IR Obstacle Sensor — Tishvi Sample Sketch");
  Serial.println("------------------------------------------");
  Serial.println("Open Serial Monitor at 9600 baud.");
  Serial.println("Adjust the blue potentiometer to set detection distance.");
  Serial.println();
}

void loop() {
  // ── Read sensor ──────────────────────────────────────────
  // LM393 comparator output: LOW = obstacle detected, HIGH = clear
  bool sensorValue = digitalRead(IR_OUT_PIN);

  // ── React to state ──────────────────────────────────────
  if (sensorValue == LOW) {
    // Object detected
    digitalWrite(LED_PIN, HIGH);          // Turn on built-in LED

    // Only print when state changes (avoids spamming Serial Monitor)
    if (lastState != LOW) {
      Serial.println("🔴 OBSTACLE DETECTED  — OUT pin is LOW");
    }
  } else {
    // No object in range
    digitalWrite(LED_PIN, LOW);           // Turn off built-in LED

    if (lastState != HIGH) {
      Serial.println("🟢 Path clear         — OUT pin is HIGH");
    }
  }

  lastState = sensorValue;  // Remember current state for next loop
  delay(50);                // 50 ms polling rate — fast enough for most applications
}