Air Conditioner Controller

/*

 Wiring/instructions for the LCD was done according to:
 https://blog.jongallant.com/2015/10/particle-photon-lcd-setup/
 
 Wiring/instructions for the DHT-22 was done according to:
 https://learn.adafruit.com/dht?view=all
 
*/

#include "application.h"

#include "LiquidCrystal/LiquidCrystal.h"

#include <Adafruit_DHT_Particle.h>

#define DHTPIN D6     // what pin we're connected to

#define DHTTYPE DHT22		// DHT 22 (AM2302)

// Connect pin 1 (on the left) of the sensor to +5V
// Connect pin 2 of the sensor to whatever your DHTPIN is
// Connect pin 4 (on the right) of the sensor to GROUND
// Connect a 10K resistor from pin 2 (data) to pin 1 (power) of the sensor

DHT dht(DHTPIN, DHTTYPE);

// loopCount is what we are going to use as our countdown for the overshooting
int loopCount;
// overshootTime is the amount of time you want the air conditioner 
// on after it reaches the right temp (in sec)
int overshootTime = 300;
// thresholdTemp is the temperature that you want the device to turn on at
float thresholdTemp = 75.0;
// averageIndex takes the average of the last five seconds. 
// This is so I avoid accidental spikes in reading from DHT22
int averageIndex = 0;
// averageTemp is the three second average
int averageTemp = 0;

// average1 and average2 are temporary bits for the average.
int average1 = 0;
int average2 = 0;
    


// Set up the liquid crystal with the order of how you wired 
// (in ascending order so easier)
LiquidCrystal lcd(D0, D1, D2, D3, D4, D5);

// Set D7 as our relay switch
int relaySwitch = D7;

// ########################### SETUP ###########################
void setup() {
    
    // set our air conditioner switch to be an output
    pinMode(relaySwitch, OUTPUT);
    
    // start the DHT-22 device
	dht.begin();
	
	// set loopCount to 0
	loopCount = 0;
	
	// wait a couple seconds for the DHT-22 to initialize
	delay(2000);
    
    // set up the LCD's number of columns and rows: 
    lcd.begin(16,2);
    // Print Temp: to the LCD.
    lcd.print("Temp: ");
}

// ########################### LOOP ###########################
void loop() {
  // set the cursor to column 6 ("Test: " takes up 6 characters), line 0
  lcd.setCursor(6, 0);

// Reading temperature or humidity takes about 250 milliseconds
	float h = dht.getHumidity();
// Read temperature as Celsius
	float t = dht.getTempCelcius();
// Read temperature as Farenheit
	float f = round(dht.getTempFarenheit()*100)/100;
  
    // onOff will indicate whether the air conditioner is on or off. This is for logging.
    String onOff = "OFF";
    
// Check if any reads failed and exit early (to try again).
	if (isnan(h) || isnan(t) || isnan(f)) {
		//lcd.print("Failed to read DHT!");
		return;
	}
    
    // increase the average index
    averageIndex++;
    
    // if the index is 0 that means that two samples have just 
    // been taken so we can average all three together
    if ((averageIndex%3) == 0){
        averageTemp = (average1 + average2 + f)/3;
    } else if ((averageIndex%3) == 1){
        average1 = f;
    } else if ((averageIndex%3) == 2){
        average2 = f;
    }
    
    
    // display on the screen the current temperature in farenheight
    lcd.print(String(int(f)) + " *F       ");
	
	// we have a one second delay
	delay(1000);

    // if the averageTemp is above the thresholdTemp
	if (averageTemp > thresholdTemp){
	    // set the cursor on the second row
	    lcd.setCursor(0,1);
	    // display to user that the device is on
	    lcd.print("ON, above " + String(thresholdTemp) + " *F      ");
	    // set the loopCount to be the overshootTime
	    loopCount = overshootTime;
	    // set the relaySwitch to LOW (which will turn on the air conditioner)
	    digitalWrite(relaySwitch, LOW);
	    // set the string that gets sent to IFTTT to ON
	    onOff = "ON";
	    
	} else if (loopCount > 0){
	    // set the cursor on the second row
	    lcd.setCursor(0,1);
	    // display to the user that the device is on and how much time is remaining
	    lcd.print("ON, wait: " + String(loopCount) + " s     ");
	    // decrease the loopCount
	    loopCount--;
	    // set the relaySwitch to LOW (which will turn on the air conditioner)
	    digitalWrite(relaySwitch, LOW);
	    // set the string that gets sent to IFTTT to ON
	    onOff = "ON";
	}
	else{
	    // set the cursor on the second row
	    lcd.setCursor(0,1);
	    // display to the user that the device is off
	    // and it's because the temp is below threshold
	    lcd.print("OFF, below " + String(thresholdTemp) + " *F     ");
	    // set the loopCount to 0 which will prevent it 
	    // from turning on unless averageTemp is above threshold
	    loopCount = 0;
	    // set the relaySwitch to HIGH (which will turn off the air conditioner)
	    digitalWrite(relaySwitch, HIGH);
	    // set the string that gets sent to IFTTT to OFF
	    onOff = "OFF";
	}    
	
	// Every ten seconds we're going to publish the current temperature 
	// and the status of whether or not the air conditioner is on or off
	if ((averageIndex%10) == 0 && onOff == "ON") {
        Particle.publish("AirConditionerController", String(f) + "|||" + onOff);
    }
	
}