void setup() {
  // Set pins as input or output
  pinMode(D0, OUTPUT);     // LED 1
  pinMode(D7, OUTPUT);     // LED 2
  pinMode(D5, INPUT);      // Echo Pin (Input)
  pinMode(D4, OUTPUT);     // Trig Pin (Output)
  pinMode(D6, OUTPUT);     // LED 3
}

void loop() {
  long duration;
  int distance;

  // Generate a short pulse on Trig pin
  digitalWrite(D4, LOW);
  delayMicroseconds(2);
  digitalWrite(D4, HIGH);
  delayMicroseconds(10);
  digitalWrite(D4, LOW);

  // Measure the duration of echo pulse on Echo pin
  duration = pulseIn(D5, HIGH);

  // Calculate distance in centimeters
  distance = duration * 0.0343 / 2;

  // Show distance on Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Turn on LEDs based on measured distance
  if (distance < 20) {
    digitalWrite(D0, HIGH);  // LED 1
    digitalWrite(D7, HIGH);  // LED 2
    digitalWrite(D6, HIGH);  // LED 3
  } else if (distance >= 20 && distance < 50) {
    digitalWrite(D0, HIGH);
    digitalWrite(D7, HIGH);
    digitalWrite(D6, LOW);
  } else if (distance >= 50 && distance < 90) {
    digitalWrite(D0, HIGH);
    digitalWrite(D7, LOW);
    digitalWrite(D6, LOW);
  } else {
    digitalWrite(D0, LOW);
    digitalWrite(D7, LOW);
    digitalWrite(D6, LOW);
  }

  delay(100);  // Adjust the wait time as needed
}
Week 06
