// Intervalometer with Pot
// by MauricioC90
// Instructables.com
//

#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2); 

const int buttonSelectPin = 3;     // the number of the pushbutton pin
const int buttonEnterPin = 4; 
const int potReadPin = A0;
const int shutterPin = 13;
unsigned long potValue = 0;
unsigned long timeInterval = 0; // time interval for shutter in secs, limited from 5 to 999 secs
unsigned long interval = 0;
unsigned long timeLapse = 0; // how long in minutes will be tacking pictures, limited to 999 mins
unsigned long totalShots = 0; // how many shots i.e.: timeLapse / timeInterval
String stringOne = ""; // user for concatenation of strings
String stringTwo = "";
String stringThree = "";
unsigned long shutterDelay = 100; // keep shutter on by milisecs.

void setup() {
  
  pinMode(buttonSelectPin, INPUT);
  pinMode(buttonEnterPin, INPUT);
  pinMode(shutterPin, OUTPUT);

  lcd.init(); 
  lcd.backlight();   // Turn on the backligt (try lcd.noBaklight() to turn it off)
  lcd.setCursor(0,0); //First line
  lcd.print("Intervalometer");
  lcd.setCursor(0,1); //Second line
  lcd.print("Push Any button");

  while (!digitalRead(buttonSelectPin) && !digitalRead(buttonEnterPin)) {}   // wait for any button 
}

// the loop function runs over and over again forever
void loop() {
  
  delay(500); // to avoid double command

  while(true) {

   showParameters(); // shows the interval and the total time
   lcd.setCursor(0,1);
   lcd.print("Sel or Enter");
   
   while (!digitalRead(buttonSelectPin) && !digitalRead(buttonEnterPin)) {}   // wait for any button 
   
   if (digitalRead(buttonSelectPin)) { //get parameter for time-lapse
     delay(500); // to avoid double command
     timeInterval = getTimeInterval();
     timeLapse = getTimeLapse();
    delay(500); // to avoid double command
  }
  
   if (digitalRead(buttonEnterPin)) {

     if (timeInterval > 0 && timeLapse > 0) {
      totalShots = timeLapse * 60 / timeInterval;
      startTimeLapse(totalShots, timeInterval*1000);
                                              }
                                    }
              }
}  

// shows two variables of time lapse in display
void showParameters(void){
    lcd.clear();
    lcd.setCursor(0,0);
    stringOne = "i:";
    stringTwo = " L:";
    stringThree = stringOne + timeInterval + "s "+ stringTwo + timeLapse + "min";
    lcd.print(stringThree);
  }

int getTimeInterval(void) {
  delay(500); 
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Use pot + Enter");
  lcd.setCursor(0,1);
  lcd.print("i (secs): ");
    
  while(!digitalRead(buttonEnterPin)){ // select value until Enter
    lcd.setCursor(10,1);
    potValue = analogRead(potReadPin)/5; //from 0 to 200 aprox.
    stringOne = potValue;
    stringTwo = stringOne + "    ";
    lcd.print(stringTwo);}

  return potValue;
}

int getTimeLapse(void) {
  delay(500); 
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Use pot + Enter");
  lcd.setCursor(0,1);
  lcd.print("T (mins): ");
    
  while(!digitalRead(buttonEnterPin)){ // select value until Enter
    lcd.setCursor(10,1);
    potValue = analogRead(potReadPin)/5; //from 0 to 200 aprox.
    stringOne = potValue;
    stringTwo = stringOne + "   ";
    lcd.print(stringTwo);}

  return potValue;
}

// takes n pictures as defined in the variable shots
void startTimeLapse(unsigned long shots, unsigned long interval) {

  showParameters(); 
  
  while (shots) {
    stringOne = shots;
    stringTwo = stringOne + "    ";
    lcd.setCursor(0,1);
    lcd.print(stringTwo); // prints remaining shots
    
    takePicture();

    shots--;

    delay(interval-shutterDelay);
    
   }
}

void takePicture(void) {
  digitalWrite(shutterPin, HIGH);
  delay(shutterDelay);
  digitalWrite(shutterPin, LOW);
}