Arduino Protothreading Example v1.1
by Drew Alden (@ReanimationXP) 1/12/2016

- Update: v1.1 - 8/18/17
  Arduino 1.6.6+ prototyping changed, small fixes.
  (create functions ahead of use, removed foreach and related library).

  Note that TimedAction is now out of date. Be sure to read notes about
  TimedAction and WProgram.h / Arduino.h errors.
*/

//COMPONENTS

/*
This code was made using the Sunfounder Arduino starter kit's blue LCD.
It can be found at Amazon.com in a variety of kits.
*/

//THIRD-PARTY LIBRARIES
//these must be manually added to your Arduino IDE installation

//TimedAction
//allows us to set actions to perform on separate timed intervals
//http://playground.arduino.cc/Code/TimedAction
//http://wiring.uniandes.edu.co/source/trunk/wiring/firmware/libraries/TimedAction

#include <TimedAction.h>
//NOTE: This library has an issue on newer versions of Arduino. After
//      downloading the library you MUST go into the library directory and
//      edit TimedAction.h. Within, overwrite WProgram.h with Arduino.h


//NATIVE LIBRARIES

#include <LiquidCrystal.h>
    /*
      LiquidCrystal Library - Hello World

     Demonstrates the use a 16x2 LCD display.  The LiquidCrystal
     library works with all LCD displays that are compatible with the
     Hitachi HD44780 driver. There are many of them out there, and you
     can usually tell them by the 16-pin interface.

     One example circuit:
     * LCD RS pin to digital pin 12.
     * LCD Enable/E/EN pin to digital pin 11
     * LCD D4 pin to digital pin 5
     * LCD D5 pin to digital pin 4
     * LCD D6 pin to digital pin 3
     * LCD D7 pin to digital pin 2
     * LCD R/W pin to ground
     * LCD VSS pin to ground
     * LCD VCC/VDD pin to 5V
     * 10K resistor:
     * ends to +5V and ground
     * wiper (middle) to LCD VO pin (pin 3)
     *Backlit Displays:
     * LCD K pin to ground (if present)
     * LCD A pin to 220ohm (red red black black (brown)) resistor, then
       resistor to pin 9

     This example code is in the public domain.

     http://www.arduino.cc/en/Tutorial/LiquidCrystal
     */

//GLOBALS
int backlightPin = 9;   // used for backlight fading

int timerCounter = 0;   // incrementing counter. will crash eventually.
int stringNo = 0;       //which text string to show
//                   "16 CHARACTER MAX"
char* stringArray[]={"Check it out... ",
                     "I have 3 threads",
                     "going at once...",
                     "Cool, huh?! :D  "};

//INIT

// This should probably be done inside setup(), but whatever.
// initialize the LCD library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

//FUNCTIONS

//this is our first task, print an incrementing number to the LCD
void incrementNumber(){
   // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // add one to the counter, then display it.
  timerCounter = timerCounter + 1;
  lcd.print(timerCounter);
}

//our second task, fires every few seconds and rotates text strings
void changeText(){
  // Print a message to the LCD.
  lcd.setCursor(0, 0);
  lcd.print(stringArray[stringNo]);

  //nasty hack to get number of Array elements
  if (stringNo >= sizeof(stringArray)/sizeof(char *)){
    stringNo = 0;
    changeText();
  }
  else{
    stringNo = stringNo + 1;
  }
}

//Create a couple timers that will fire repeatedly every x ms

//edit: these lines used to be in front of incrementNumber and changeText
//      functions. this didn't work because the functions weren't defined yet!
TimedAction numberThread = TimedAction(700,incrementNumber);
TimedAction textThread = TimedAction(3000,changeText);

// where's our third task? well, it's the main loop itself :) the task
// which repeats most often should be used as the loop. other
// tasks are able to "interrupt" the fastest repeating task.


void setup() {
  //define the LCD's number of columns and rows:
  lcd.begin(16, 2);
  //fire changeText once to paint the initial string [0]
  changeText();
}


void loop() {

  //check on our threads. based on how long the system has been
  //running, do they need to fire and do work? if so, do it!
  numberThread.check();
  textThread.check();

  //third task, fade in backlight from min to max brightness
  //in increments of 5 points:
  digitalWrite(13, HIGH);
  for (int fadeValue = 0 ; fadeValue <= 255; fadeValue += 10) {

    //wait a second, why am i checking on the threads here? because
    //this is a for loop. you must check on your threads during ANY
    //loops that occur, including the main one!
    numberThread.check();
    textThread.check();

    //sets the value (range from 0 to 255):
    analogWrite(backlightPin, fadeValue);

    // wait for 20 milliseconds to see the dimming effect
    // keep delays on the main loop SHORT. these WILL prevent
    // other threads from firing on time.
    delay(20);
  }

  //fade out from max to min in increments of 5 points:
  digitalWrite(13, LOW);
  for (int fadeValue = 255 ; fadeValue >= 0; fadeValue -= 10) {

    //check on our threads again
    numberThread.check();
    textThread.check();

    //sets the value (range from 0 to 255):
    analogWrite(backlightPin, fadeValue);

    //wait for 20 milliseconds to see the dimming effect
    delay(20);
  }

  /*

  For some scrolling message fun in the future...

  lcd.setCursor(15,0);  // set the cursor to column 15, line 0
    for (int positionCounter1 = 0; positionCounter1 < 26; positionCounter1++)
    {
      lcd.scrollDisplayLeft();
      //Scrolls the contents of the display one space to the left.
      lcd.print(array1[positionCounter1]);
      // Print a message to the LCD.
      delay(tim);  //wait for 250 microseconds
    }
    lcd.clear();
    //Clears the LCD screen and positions the cursor in the upper-left corner.

    lcd.setCursor(15,1);  // set the cursor to column 15, line 1
    for (int positionCounter = 0; positionCounter < 26; positionCounter++){
      lcd.scrollDisplayLeft();
      //Scrolls the contents of the display one space to the left.
      lcd.print(array2[positionCounter]);  // Print a message to the LCD.
      delay(tim);  //wait for 250 microseconds
    }
    lcd.clear();
    //Clears the LCD screen and positions the cursor in the upper-left corner.

}