#define IR_SENSOR_PIN D1  // Define the pin connected to the IR sensor OUT
#define RELAY_PIN D2      // Define the pin connected to the relay IN
#define TRIG_PIN D3       // Define the pin connected to the ultrasonic sensor Trig
#define ECHO_PIN D4       // Define the pin connected to the ultrasonic sensor Echo

const int thresholdDistance = 10;  // Threshold distance in cm (set based on your glass height)

void setup() {
  pinMode(IR_SENSOR_PIN, INPUT);  // Set IR sensor pin as input
  pinMode(RELAY_PIN, OUTPUT);     // Set relay pin as output
  pinMode(TRIG_PIN, OUTPUT);      // Set ultrasonic sensor Trig pin as output
  pinMode(ECHO_PIN, INPUT);       // Set ultrasonic sensor Echo pin as input
  
  digitalWrite(RELAY_PIN, LOW);   // Initialize the relay to be off
  Serial.begin(9600);           // Start the serial communication at 115200 baud rate
}

void loop() {
  int irValue = digitalRead(IR_SENSOR_PIN);  // Read the value from the IR sensor
  int distance = measureDistance();          // Measure the distance using the ultrasonic sensor

  if (distance <= thresholdDistance && distance > 0) {  
    // If the water level is at or above the threshold
    irValue = HIGH;  // Override the IR sensor value to stop the relay
    Serial.println("Glass is full, stopping water...");
  }

  if (irValue == LOW) {  // If IR sensor detects an object (LOW output)
    digitalWrite(RELAY_PIN, LOW);  // Turn on the relay
    Serial.println("Object detected! Relay ON.");
  } else {  // If no object is detected or glass is full
    digitalWrite(RELAY_PIN, HIGH);  // Turn off the relay
    Serial.println("No object detected or glass is full. Relay OFF.");
  }
  
  delay(500);  // Delay for half a second before repeating the loop
}

int measureDistance() {
  // Function to measure the distance using the ultrasonic sensor
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  
  long duration = pulseIn(ECHO_PIN, HIGH, 30000);  // Wait up to 30ms for a valid pulse
  
  if (duration == 0) {
    return 0;  // Return 0 if no valid echo was received
  }

  return duration * 0.034 / 2;  // Convert the duration to distance in cm
}