//Stop Light v3.0

// v3.0 incorporates 
//   -  a DHT temperature/humidity sensor.
//   -  use of NewPing library for speed of sound calculation

// v2.0 incorporate a calibration button to set the desired distance
// from the car to the end of the garage.  Pressing the button for 3 seconds
// will set the red light distance to the current location of the car and
// set the yellow light to be 1/3 of the distance from the red point to the green point.


//Definition Section
#include <DHT.h>
#include <NewPing.h>

#define DHTPIN 3     // Digital pin connected to the DHT sensor
#define greenledpin 10
#define yellowledpin 11
#define redledpin 12
#define buttonpin 2 
#define DHTTYPE DHT22   // DHT 22
#define TRIGPIN  9 
#define ECHOPIN  8 
#define MAX_DISTANCE 400
DHT dht(DHTPIN, DHTTYPE);
NewPing sonar(TRIGPIN, ECHOPIN, MAX_DISTANCE) ;



int counter = 0;
int green = 400;
int yellow = 150;
int red = 30;
int waittime = 50 ; //wait before looping
int switchState = 0 ;
// End Definition Section

float duration ;
float distance ;
float soundsp;
float soundcm;

void setup() {
  // Initialization Section
  pinMode(TRIGPIN, OUTPUT);
  pinMode(ECHOPIN, INPUT);
  pinMode(greenledpin, OUTPUT);
  pinMode(yellowledpin, OUTPUT);
  pinMode(redledpin, OUTPUT);
  pinMode(buttonpin, INPUT) ;
  pinMode (buttonpin, INPUT) ;
  pinMode (DHTPIN, INPUT) ;

  Serial.begin(9600);
  dht.begin () ;
}
// End Initialization Section

void loop() {

 // Wait a few seconds between measurements.

  delay(1000);

  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  float h = dht.readHumidity();
  // Read temperature as Celsius (the default)
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit (isFahrenheit = true)
  // float f = dht.readTemperature(true);

  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }


// Distance Measurement Section - Library Calculation
duration = sonar.ping() ;
soundsp = 331.4 + (0.606 * t) + (0.0124 * h) ;
soundcm = soundsp/10000 ;
distance = (duration / 2) * soundcm ;
Serial.println (distance) ;

  digitalWrite(redledpin, LOW);
  digitalWrite(yellowledpin, LOW);

// End Distance Measurement Section - Library Calculation

// Distance Calibration section
  switchState = digitalRead (buttonpin);
  if (switchState == HIGH) {
    digitalWrite (greenledpin, LOW) ; //all leds off to confirm button press
    digitalWrite (yellowledpin, LOW);
    digitalWrite (redledpin, LOW) ;

    delay (3000) ; // wait 3 seconds and see if button is still pressed
    switchState = digitalRead (buttonpin) ;
    if (switchState == HIGH) {
      red = distance ; //reset red to current distance to car
      yellow = red + .33 * (green - red) ; // reset yellow to 1/3 of distance between red and green

      for (int i = 1; i <= 5; i++)    { //flash all leds to confirm changes have been completed.
        digitalWrite (greenledpin, HIGH) ;
        digitalWrite (yellowledpin, HIGH);
        digitalWrite (redledpin, HIGH) ;
        delay (200) ;
        digitalWrite (greenledpin, LOW) ;
        digitalWrite (yellowledpin, LOW);
        digitalWrite (redledpin, LOW) ;
        delay (200) ;
      }
    }
  }
// End Distance Calibration Section


  if (distance > green) {
    digitalWrite (greenledpin, LOW) ;
    waittime = 2;
  }

  else if (distance < red / 2) {
    digitalWrite (greenledpin, LOW) ;
    digitalWrite (redledpin, HIGH);
    delay (125) ;
    digitalWrite (redledpin, LOW) ;
    waittime = 2 ;
  }
  else if (distance < red) {
    digitalWrite(greenledpin, LOW);
    digitalWrite (redledpin, HIGH);
    waittime = 2 ;
  }

  else if (distance < yellow) {
    digitalWrite(greenledpin, LOW);
    digitalWrite(yellowledpin, HIGH);
    waittime = 2;
  }

  else {
    digitalWrite(greenledpin, HIGH);
    waittime = 2 ;
  }

 //Serial.print ("Red = ") ;
 //Serial.print (red) ;
 //Serial.print ("cm, Yellow = ") ;
 //Serial.print (yellow) ;
 //Serial.print ("cm, Green = ") ;
 //Serial.print (green) ;
 //Serial.println ("cm.");
  // Serial.print ("Two-way travel time = ");
  // Serial.print (duration);
  // Serial.println (" ms.");
  // Serial.print ("Estimated distance = ");
  // Serial.print (distance);
  // Serial.println (" cm.");
  // Serial.println (" ");


  // Serial.println (waittime) ;
  // Serial.print ("Red distance = ") ;
  // Serial.println (red) ;

  delay(waittime);
}