LCD Shield For Arduino

This is a very popular LCD Keypad shield for Arduino or Freeduino board. It can be directly plug onto the Arudino board, no soldering or fly-wiring needed. A 16x2 HD44780 compatible LCD, White character & Blue backlight.

This Shield uses Arudino LCD4Bit library.

Pin Allocation

Sample Code

Example use of LCD4Bit_mod library

LCD4Bit_mod Library Download

				//#include <LCD4Bit_mod.h> //create object to control an LCD.  //number of lines in display=1LCD4Bit_mod lcd = LCD4Bit_mod(2); //Key messagechar msgs[5][15] = {"Right Key OK ",                     "Up Key OK    ",                     "Down Key OK  ",                     "Left Key OK  ",                     "Select Key OK" };int  adc_key_val[5] ={30, 150, 360, 535, 760 };int NUM_KEYS = 5;int adc_key_in;int key=-1;int oldkey=-1;void setup() {   pinMode(13, OUTPUT);  //we'll use the debug LED to output a heartbeat  lcd.init();  //optionally, now set up our application-specific display settings, overriding whatever the lcd did in lcd.init()  //lcd.commandWrite(0x0F);//cursor on, display on, blink on.  (nasty!)   lcd.clear();  lcd.printIn("KEYPAD testing... pressing");}void loop() {adc_key_in = analogRead(0);    // read the value from the sensor  digitalWrite(13, HIGH);  key = get_key(adc_key_in);    // convert into key press	if (key != oldkey)	// if keypress is detected	{    delay(50);		// wait for debounce time    adc_key_in = analogRead(0);    // read the value from the sensor      key = get_key(adc_key_in);    // convert into key press    if (key != oldkey)				    {			      oldkey = key;      if (key >=0){      lcd.cursorTo(2, 0);  //line=2, x=0  	lcd.printIn(msgs[key]);      }    }  }  digitalWrite(13, LOW);}// Convert ADC value to key numberint get_key(unsigned int input){	int k;	for (k = 0; k < NUM_KEYS; k++)	{		if (input < adc_key_val[k])		{  return k;  }	}    if (k >= NUM_KEYS)        k = -1;     // No valid key pressed    return k;}

Example use of LiquidCrystal library

				//Sample using LiquidCrystal library#include <LiquidCrystal.h>/*******************************************************This program will test the LCD panel and the buttonsMark Bramwell, July 2010********************************************************/// select the pins used on the LCD panelLiquidCrystal lcd(8, 9, 4, 5, 6, 7);// define some values used by the panel and buttonsint 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// read the buttonsint read_LCD_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 if (adc_key_in > 1000) return btnNONE; // We make this the 1st option for speed reasons since it will be the most likely result 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); lcd.print("Push the buttons"); // print a simple message} 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;     } }}