#include <Servo.h>

Servo servo;

int trigPin = 9;
int echoPin = 10;
int servopin = 6;
long duration, distance;

int led1 = 11;
int led2 = 12;
int buzzer = 13;

void setup() {
  // put your setup code here, to run once:
pinMode (trigPin, OUTPUT);
pinMode (echoPin, INPUT);
servo.attach(servopin);
Serial.begin(9600);
pinMode (led1, OUTPUT);
pinMode (led2, OUTPUT);
pinMode (buzzer, OUTPUT);

}

void loop() {
//Transmitter functions
digitalWrite (trigPin, LOW);
delayMicroseconds(2);
digitalWrite (trigPin, HIGH);
delayMicroseconds(10);
digitalWrite (trigPin, LOW);

duration = pulseIn (echoPin, HIGH);
//Measuring distance
//speed = distance/time
//speed = distance/duration
//distance = speed*duration

distance = duration*0.034/2;


if (distance > 100) {

servo.write (180);
Serial.println (distance);
digitalWrite(led1, HIGH);
digitalWrite(led2, LOW);
digitalWrite(buzzer, HIGH);
tone(buzzer, 1500);

}


else {
  servo.write(20);
  Serial.println(distance);
  digitalWrite(led1, LOW);
digitalWrite(led2, HIGH);
digitalWrite(buzzer, LOW);
noTone(buzzer);

}

delay (50);
}