//Sample using LiquidCrystal library
#include <LiquidCrystal.h>

/*******************************************************

This program will test the LCD panel and the buttons
Mark Bramwell, July 2010

********************************************************/

// select the pins used on the LCD panel
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

// define some values used by the panel and buttons
int lcd_key     = 0;
int adc_key_in  = 0;

#define btnRIGHT  0
#define btnUP     1
#define btnDOWN   2
#define btnLEFT   3
#define btnSELECT 4
#define btnNONE   5

const int btnup = 130;
const int btndown = 306;
const int btnleft = 479;
const int btnright = 0;
const int select = 720;
const int none = 127;
const int threshold = 2;

// read the buttons
int read_LCD_buttons()
{
 adc_key_in = analogRead(A0);      // read the value from the sensor 
 // my buttons when read are centered at these valies: 0, 144, 329, 504, 741
 // we add approx 50 to those values and check to see if we are close
if (adc_key_in > none - threshold && adc_key_in < none + threshold)   return btnNONE; // We make this the 1st option for speed reasons since it will be the most likely result
if (adc_key_in > btnup - threshold && adc_key_in < btnup + threshold)   return btnUP;
if (adc_key_in > btndown - threshold && adc_key_in < btndown + threshold)   return btnDOWN;
if (adc_key_in > btnleft - threshold && adc_key_in < btnleft + threshold)   return btnLEFT;
if (adc_key_in > btnright - threshold && adc_key_in < btnright + threshold)   return btnRIGHT;
if (adc_key_in > select - threshold && adc_key_in < select + threshold)   return btnSELECT;

 return btnNONE;  // when all others fail, return this...
}//end read_LCD_Buttons

void setup()
{
 lcd.begin(16, 2);              // start the library
 lcd.setCursor(0,0);
 lcd.print("Push the buttons"); // print a simple message
}//end setup
 
void loop()
{
 lcd.setCursor(9,1);            // move cursor to second line "1" and 9 spaces over
 lcd.print(millis()/1000);      // display seconds elapsed since power-up


 lcd.setCursor(0,1);            // move to the begining of the second line
 lcd_key = read_LCD_buttons();  // read the buttons

 switch (lcd_key)               // depending on which button was pushed, we perform an action
 {
   case btnRIGHT:
     {
     lcd.print("RIGHT ");
     break;
     }
   case btnLEFT:
     {
     lcd.print("LEFT   ");
     break;
     }
   case btnUP:
     {
     lcd.print("UP    ");
     break;
     }
   case btnDOWN:
     {
     lcd.print("DOWN  ");
     break;
     }
   case btnSELECT:
     {
     lcd.print("SELECT");
     break;
     }
     case btnNONE:
     {
     lcd.print("NONE  ");
     break;
     }
 }//end switch

}//end loop