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
|
Pin |
Function |
|
Analog 0 |
Button (select, up, right, down and left) |
|
Digital 4 |
DB4 |
|
Digital 5 |
DB5 |
|
Digital 6 |
DB6 |
|
Digital 7 |
DB7 |
|
Digital 8 |
RS (Data or Signal Display Selection) |
|
Digital 9 |
Enable |
|
Digital 10 |
Backlit Control |
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; } }}
