#define echo 2
#define trig 3
#define outA 8 // Red LED
#define outB 9 // Green LED
#define outC 10 // Buzzer

float duration; // time taken by the pulse to return back
float distance; // one-way distance travelled by the pulse

const int intredDistance = 100
; // the minimum distance upon which the sensor is able to sense any object

void setup() {
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);

  pinMode(outA, OUTPUT);
  digitalWrite(outA, LOW);

  pinMode(outB, OUTPUT);
  digitalWrite(outB, LOW);

  pinMode(outC, OUTPUT);
  digitalWrite(outC, LOW);

  Serial.begin(9600);
}

void loop() {
  time_Measurement();
  distance = (float)duration * (0.0343 / 2);  // calculate the one-way distance travelled by the pulse
  Serial.println(distance);
  alarm_condition();
}

void time_Measurement() {
  // function to measure the time taken by the pulse to return back
  digitalWrite(trig, LOW);
  delayMicroseconds(2);

  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

  duration = pulseIn(echo, HIGH);
}

void alarm_condition() {
  // function to execute the output commands based on the sensor input
  if (distance <= intredDistance) {
    digitalWrite(outA, HIGH);
    digitalWrite(outB, LOW);
    analogWrite(outC, 100);
  } else {
    digitalWrite(outA, LOW);
    digitalWrite(outB, HIGH);
    analogWrite(outC, 0);
  }
}