#include <Servo.h>
int trig=7;
int echo=6;
int timeInMicro;
int distanceIncm;
Servo servo;
void setup() {
  Serial.begin(9600);
  pinMode(7, OUTPUT);
  pinMode(6, INPUT);
  servo.attach(3);

}

int distance()
{
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);
  timeInMicro=pulseIn(echo,HIGH);
  distanceIncm=timeInMicro/29/2;
  Serial.println(distanceIncm);
  delay(100);
return distanceIncm;
}


void loop() 
{
int level=distance();
if (level <=30)
  {
    servo.write(90);
    //Serial.println("dust bin open");
  }
else
{
  servo.write(0);
  //Serial.println("dust bin close");
}  



}