#include //servo library Servo servo; int trigPin = 5; int echoPin = 6; int servoPin = 7; int led= 10; long duration, dist, average; long aver[3]; //array for average void setup() { Serial.begin(9600); servo.attach(servoPin); pinMode(trigPin, OUTPUT); pinMode(echoPin, INPUT); servo.write(0); //close cap on power on delay(100); servo.detach(); } void measure() { digitalWrite(10,HIGH); digitalWrite(trigPin, LOW); delayMicroseconds(5); digitalWrite(trigPin, HIGH); delayMicroseconds(15); digitalWrite(trigPin, LOW); pinMode(echoPin, INPUT); duration = pulseIn(echoPin, HIGH); dist = (duration/2) / 29.1; //obtain distance } void loop() { for (int i=0;i<=2;i++) { //average distance measure(); aver[i]=dist; delay(10); //delay between measurements } dist=(aver[0]+aver[1]+aver[2])/3; if ( dist<50 ) { //Change distance as per your need servo.attach(servoPin); delay(1); servo.write(0); delay(3000); servo.write(150); delay(1000); servo.detach(); } Serial.print(dist); }