#include <Servo.h>
Servo myservo; 
const int trigPin = 9;
const int echoPin = 8;
long duration;
float distance;
void setup() 
{
 myservo.attach(7);
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT); 
 myservo.write(0);
}
void loop() 
{
 Serial.begin(9600);
 digitalWrite(trigPin, LOW);
 delayMicroseconds(2);
 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10);
 digitalWrite(trigPin, LOW);
 duration = pulseIn(echoPin, HIGH);
 distance = 0.034*(duration/2);
 Serial.println(distance);
 if (distance <=50)
 {
 myservo.write(0+160);
 delay(1000);
 }
 else 
 {
 myservo.write(0);
 }
 delay(300);
}