distance.ino

#define trigPin 13
#define echoPin 12
#define led 11
#define led2 10
#define threshold_distance 10

void setup() {
  Serial.begin (9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(led, OUTPUT);
  pinMode(led2, OUTPUT);
}

void loop() {
  long duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
//  delayMicroseconds(1000); 
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;
  if (distance < 4) {       // This is where the LED On/Off happens
    digitalWrite(led,HIGH); // When the Red condition is met, the Green LED should turn off
  digitalWrite(led2,LOW);
}
  else {
    digitalWrite(led,LOW);
    digitalWrite(led2,HIGH);
  }
  if (distance >= 200 || distance <= 0){
    Serial.println("Out of range");
  }
  else {
    Serial.print(distance);
    Serial.println(" cm");
  }
  if(distance < threshold_distance){
    print();
  }
  delay(500);
}

void print(){
  Serial.print("Dustbin Full");
  Serial.print("\n");
}

Introduction

It is a sample code to work with HC-SR04 Ultrasonic Distance Measuring Module. I am using this for my 'Smart Dustbin' project.