Calb.ino

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

  Mark Bramwell, July 2010

  This program will test the LCD panel and the buttons.When you push the button on the shield，
  the screen will show the corresponding one.
 
  Connection: Plug the LCD Keypad to the UNO(or other controllers)

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

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

If we use our keypadShield hardware then we can get these values like 0, 144, 329, 504, 741,
but now we are using our circuit which is similar to this one. so first you have to find out 
what values are generated for different key press and then justify it.
  
**************************************************************************************/



#include <LiquidCrystal.h>

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

// 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

int read_LCD_buttons(){               // read the buttons
    adc_key_in = analogRead(0);       // 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
    // We make this the 1st option for speed reasons since it will be the most likely result

    if (adc_key_in > 1000) return btnNONE; 

    // For V1.1 us this threshold
    if (adc_key_in < 50)   return btnRIGHT;  
    if (adc_key_in < 250)  return btnUP; 
    if (adc_key_in < 450)  return btnDOWN; 
    if (adc_key_in < 650)  return btnLEFT; 
    if (adc_key_in < 850)  return btnSELECT;  

   // For V1.0 comment the other threshold and use the one below:
   /*
     if (adc_key_in < 50)   return btnRIGHT;  
     if (adc_key_in < 195)  return btnUP; 
     if (adc_key_in < 380)  return btnDOWN; 
     if (adc_key_in < 555)  return btnLEFT; 
     if (adc_key_in < 790)  return btnSELECT;   
   */

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

void setup(){
   lcd.begin(16, 2);               // start the library
   lcd.setCursor(0,0);             // set the LCD cursor   position 
   lcd.print("Push the buttons");  // print a simple message on the LCD
}
 
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:{             //  push button "RIGHT" and show the word on the screen
            lcd.print("RIGHT ");
            break;
       }
       case btnLEFT:{
             lcd.print("LEFT   "); //  push button "LEFT" and show the word on the screen
             break;
       }    
       case btnUP:{
             lcd.print("UP    ");  //  push button "UP" and show the word on the screen
             break;
       }
       case btnDOWN:{
             lcd.print("DOWN  ");  //  push button "DOWN" and show the word on the screen
             break;
       }
       case btnSELECT:{
             lcd.print("SELECT");  //  push button "SELECT" and show the word on the screen
             break;
       }
       case btnNONE:{
             lcd.print("NONE  ");  //  No action  will show "None" on the screen
             break;
       }
   }
}