If you want to buy the entire combo including already programmed Arduino board then CLICK HERE 

#include <Servo.h>

const int trigPin = 9;
const int echoPin = 8;
long duration;
int distance;

Servo myServo;
void setup()
{
myServo.attach(7);
pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
Serial.begin(9600);
}

void loop() {
distance = calculateDistance();

myServo.write(0);
if ( distance < 5)
{ myServo.attach(7);
myServo.write(160);
delay(500);
myServo.write(0);
delay(1000);

}
else{
myServo.detach();
}
Serial.println(distance);
}
int calculateDistance(){

digitalWrite(trigPin, LOW);
delayMicroseconds(5);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
distance= duration*0.034/2;
return distance;
}

IF YOU ARE GETTING A STRAY ERROR THEN CLICK HERE 

CIRCUIT DIAGRAM