void #include <Servo.h>
int echoPin=6;
int trigPin=7;
long duration;
int distanceCm;
Servo servo_9;
void setup()
{
servo_9.attach(9);
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
}
void loop()
{
digitalWrite(trigPin,LOW);
delayMicroseconds(2);
digitalWrite(trigPin,HIGH);
delayMicroseconds(2);
digitalWrite(trigPin,LOW);
duration = pulseIn(echoPin,HIGH);
distanceCm=duration*0.034/2;
if (distanceCm <= 20){
servo_9.write(90);
delay(5000);
}
else
servo_9.write(0);
}setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}