#include <Servo.h> 
Servo myservo; 
double distance; 

double readUltrasonicDistance(int triggerPin, int echoPin)
{
  pinMode(triggerPin, OUTPUT);
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  pinMode(echoPin, INPUT);
  return pulseIn(echoPin, HIGH);
}

void setup() {
  myservo.attach(9); 
}

void loop() {
  distance = readUltrasonicDistance(3, 2) / 58;
  distance = map(distance, 0, 400, 180, 0);
  myservo.write(distance);
  delay(10);
}