/*
Project: Ultrasonic sensor HC SR04, 5V servo motor
Function: Ultrasonic radar. Use of Processing software for visualisation
*/
//*******************************************************************************
#include <Servo.h>//include library code
//*******************************************************************************
const int trigPin = 2;//ultrasonic sensor trig pin attached to digital pin 2 of Arduino Uno
const int echoPin = 3;//ultrasonic sensor trig pin attached to digital pin 3 of Arduino Uno
const int servoPin = 9;//servo motor attached to digital pin 9 PWM
//(you can use any PWM pin - 3, 9, 10, 6 or 11)
long duration;//variable for duration
int distance;//variable for distance
Servo myServo; //creates servo object
//********************************************************************************
void setup() {
  pinMode(trigPin, OUTPUT); //sets trigPin as an OUTPUT
  pinMode(echoPin, INPUT);  //sets echoPin as an INPUT
  Serial.begin(9600);//initialize the serial communication at 9600 bps
  myServo.attach(servoPin);//attach the servo to servo object
}
void loop() {
  //rotates the servo motor from 0 to 180 degrees
  for(int i=0;i<=180;i++){  
  myServo.write(i);
  delay(30);//sets delay for 30 ms
  distance = calculateDistance();//calls the function calculateDistance()
  Serial.print(i); //sends the current degree into the Serial Port
  Serial.print(","); //sends addition character right next to the previous value needed later in the Processing IDE for indexing
  Serial.print(distance); //sends the distance value into the Serial Port
  Serial.print("."); //sends addition character right next to the previous value needed later in the Processing IDE for indexing
  }
  //repeats the previous lines from 180 to 0 degrees
  for(int i=180;i>0;i--){  
  myServo.write(i);
  delay(30);//sets delay for 30 ms
  distance = calculateDistance();
  Serial.print(i);
  Serial.print(",");
  Serial.print(distance);
  Serial.print(".");
  }
}
//*************************************************************************
// Function for calculating the distance measured by the Ultrasonic sensor
int calculateDistance(){ 
  digitalWrite(trigPin, LOW); //sets the trigPin on LOW state for 2 ms
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH); //sets the trigPin on HIGH state for 10 ms
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);//sets the trigPin on LOW state
  duration = pulseIn(echoPin, HIGH); //reads the echoPin, returns the sound wave travel time in microseconds
  distance= duration*0.034/2;
  return distance;
}