/*
 Controlling a servo position using a potentiometer (variable resistor)
 by Michal Rinott <http://people.interaction-ivrea.it/m.rinott>

 modified on 8 Nov 2013
 by Scott Fitzgerald
 http://www.arduino.cc/en/Tutorial/Knob
*/

#include <Servo.h>

// constants won't change
const int TRIG_PIN  = 7;  // Arduino pin connected to Ultrasonic Sensor's TRIG pin
const int ECHO_PIN  = 6;  // Arduino pin connected to Ultrasonic Sensor's ECHO pin
const int SERVO_PIN_1 = 9; // Arduino pin connected to Servo Motor's pin
const int SERVO_PIN_2 = 10; // Arduino pin connected to Servo Motor's pin
const int DISTANCE_THRESHOLD = 5; // centimeters

Servo servo; // create servo object to control a servo
Servo servo2; // create servo object to control a servo

// variables will change:
float duration_us, distance_cm;

void setup() {
  Serial.begin (9600);       // initialize serial port
  pinMode(TRIG_PIN, OUTPUT); // set arduino pin to output mode
  pinMode(ECHO_PIN, INPUT);  // set arduino pin to input mode
  servo.attach(SERVO_PIN_1);   // attaches the servo on pin 9 to the servo object
  servo.write(0);
  servo2.attach(SERVO_PIN_2);   // attaches the servo on pin 9 to the servo object
  servo.write(0);
}

void loop() {
  // generate 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // measure duration of pulse from ECHO pin
  duration_us = pulseIn(ECHO_PIN, HIGH);
  // calculate the distance
  distance_cm = 0.017 * duration_us;

  if(distance_cm < DISTANCE_THRESHOLD) {
    servo.write(60); // rotate servo motor to 90 degree
    servo2.write(60); // rotate servo motor to 90 degree
  }
  else {
    servo.write(0);  // rotate servo motor to 0 degree
    servo2.write(0);  // rotate servo motor to 0 degree

  }
  // print the value to Serial Monitor
  Serial.print("distance: ");
  Serial.print(distance_cm);
  Serial.println(" cm");

  delay(500);
}