{"id":1305,"date":"2015-12-08T10:39:01","date_gmt":"2015-12-08T02:39:01","guid":{"rendered":"http:\/\/handsontec.com\/?page_id=1305"},"modified":"2015-12-16T09:02:46","modified_gmt":"2015-12-16T01:02:46","slug":"arduino-4-using-lcdkeypad-shield","status":"publish","type":"page","link":"https:\/\/handsontec.com\/index.php\/arduino-4-using-lcdkeypad-shield\/","title":{"rendered":"Arduino – 4 – Using LCD+Keypad Shield"},"content":{"rendered":"

How to use 16×2 Character LCD + 6-buttons Keypad Shield ?<\/span><\/h3>\n

The LCD-Keypad Shield attaches to your Arduino board to provide a 16-character by 2-line display, white character, blue back light LCD with a keypad consisting of 5 keys > “select”, “up”, “right”, “down” and “left”. With this shield you will be able to move through menus and make selections straight from one board attached to your Arduino without requiring a massive tower of shields or wiring tangling around.<\/p>\n

The LCD-Keypad Shield works perfectly in 4-bit mode with the \u201cLiquidCrystal\u201d library found in the Arduino IDE, using this library will allow you to control the LCD with only 6 digital I\/O lines. This shield provides you with the capability of pushing multiple buttons at once and combining the results. No longer will you be restrained to only 5 inputs, now you have the ability to make use of 32 different button combinations!<\/p>\n

This LCD Keypad Shield use total of 6-pins to control the LCD display which is pin-4, 5, 6, 7, 8, 9. For LCD Data, it use pin-4, 5, 6, 7, while for the RS and Enable pin, it use pin-8 and 9. The Arduino-LCD Keypad Shield are only required to plug into the Arduino main board and there was no soldering are required such as shown in figure below.<\/p>\n

\"lcd-keypad-10\"<\/a>Fig-1: Plug the LCD+Keypad Shield directly onto Arduino Board.<\/p>\n

Pins Assignment<\/span><\/h3>\n\n\n\n\n\n\n\n\n\n\n\n
Arduino Pin<\/td>\nFunction<\/td>\n<\/tr>\n
A0<\/td>\nButtons ( Select, Up, Down, Left, Right)<\/td>\n<\/tr>\n
4<\/td>\nLCD DB4<\/td>\n<\/tr>\n
5<\/td>\nLCD DB5<\/td>\n<\/tr>\n
6<\/td>\nLCD DB6<\/td>\n<\/tr>\n
7<\/td>\nLCD DB7<\/td>\n<\/tr>\n
8<\/td>\nLCD Register Select, RS<\/td>\n<\/tr>\n
9<\/td>\nLCD Enable, En<\/td>\n<\/tr>\n
10<\/td>\nPWM control for Backlight brightness<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\"lcd-keypad-3\"<\/a><\/h3>\n

Application Ideas<\/span><\/h3>\n

The below code listing demonstrate the use of this LCD+Keypad shield.<\/p>\n

\/\/==========================================================================\r\n\/\/  Author      : Handson Technology\r\n\/\/  Project     : Arduino Uno\r\n\/\/  Description : Display \"Hello World\" and 6-keys press\r\n\/\/==========================================================================\r\n\r\n\/\/Include the LiquidCrystal header file which is inside the Arduino IDE\r\n#include <LiquidCrystal.h> \r\n\r\n\/* ==== PINS ASSIGNMNET ==========\r\n * LCD RS pin to digital pin 8\r\n * LCD EN pin to digital pin 9\r\n * LCD D4 pin to digital pin 4\r\n * LCD D5 pin to digital pin 5\r\n * LCD D6 pin to digital pin 6\r\n * LCD D7 pin to digital pin 7\r\n * Backlight PWM control to Pin 10\r\n * LCD R\/W pin to ground\r\n*\/\r\n\r\n\/\/ Set the I\/O pin for LCD 4-bit mode following the library assignment: \r\n\/\/  LiquidCrystal(rs, en, d4, d5, d6, d7).\r\nLiquidCrystal lcd(8, 9, 4, 5, 6, 7);\r\n\r\nint analogPin = A0;  \/\/Define the A0 as analogPin as integer type.\r\nint adc_key_old;\r\nint adc_key_in;\r\nint NUM_KEYS = 5;\r\nint key=-1;\r\nint adc_key_val[5] ={30, 150, 360, 535, 760 }; \/\/Define the value at A0 pin \r\n                                               \/\/ when a key is pressed.\r\n\r\n\/\/ Define each key as character string type for keypress display.               \r\nchar msgs[5][15] = {\"Right Key OK \", \r\n                    \"Up Key OK    \", \r\n                    \"Down Key OK  \", \r\n                    \"Left Key OK  \", \r\n                    \"Select Key OK\"};\r\n                    \r\n                    \r\n\/*******************************************************************************\r\n* PRIVATE FUNCTION: setup()\r\n* PARAMETERS:void\r\n* RETURN:void\r\n* DESCRIPTIONS:\r\n* Define of I\/O pin as Input or Output \r\n*\r\n*******************************************************************************\/\r\n\/\/ The setup() method runs once, when the sketch starts\r\nvoid setup ()\r\n{\r\n  lcd.begin(16, 2);            \/\/ set the lcd type: 16-character by 2-lines\r\n  lcd.clear();                        \/\/ LCD screen clear\r\n  lcd.print(\"  HandsOn Tech  \");      \/\/ Send the ASCII code to the LCD for \r\n                                      \/\/ displaying the message\r\n\r\n  pinMode(10, OUTPUT);                \/\/ sets backlight pin-10 as PWM output\r\n  analogWrite(10, 125);               \/\/ Set backlight to 50% brightness \r\n    \r\n  lcd.setCursor(0,1);           \/\/ set the position of next message string: \r\n                                \/\/ 1st position at 2nd line\r\n  lcd.print(\"LCD-Keypad Sh\");    \r\n  delay(5000);                        \/\/ delay for 3000ms\r\n  lcd.clear();\r\n  lcd.setCursor(0,0);              \r\n  lcd.print(\"  HandsOn Tech  \");\r\n  lcd.setCursor(0,1);\r\n  lcd.print(\"Pls press any\"); \r\n  adc_key_old = analogRead(analogPin);\/\/ store the unpress key value \r\n}\r\n\r\n\r\n\/*******************************************************************************\r\n* PRIVATE FUNCTION: loop()\r\n* PARAMETERS: void\r\n* RETURN: void\r\n* DESCRIPTIONS:\r\n* Non-Stop looping \r\n*******************************************************************************\/\r\nvoid loop()\r\n{\r\n  adc_key_in = analogRead(analogPin);  \/\/ Read the value at analogPin A0 and store \r\n                                       \/\/ the value in the adc_key_in register\r\n  adc_key_in = get_key(adc_key_in);    \/\/ Send the adc_key_in value to\r\n                                       \/\/ get_key() subroutine.\r\n  lcd.setCursor(0, 1);                 \r\n  lcd.print(msgs[adc_key_in]);         \/\/ Display message with msgs[] \r\n                                       \/\/ according to adc_key_in value\r\n}\r\n  \r\n\r\n\/*******************************************************************************\r\n* PRIVATE FUNCTION: get_key\r\n* PARAMETERS: integer\r\n* RETURN:unsigned int input\r\n* DESCRIPTIONS:\r\n* convert the ADC value to number between 0 to 4\r\n*******************************************************************************\/\r\nint get_key(unsigned int input)\r\n{\r\n  int k;\r\n    \r\n  for (k = 0; k < NUM_KEYS; k++)\r\n  {\r\n    if (input < adc_key_val[k])\r\n    {\r\n           \r\n    return k;\r\n        }\r\n  }\r\n    \r\n    if (k >= NUM_KEYS)\r\n        k = -1;     \/\/ No valid key pressed\r\n    \r\n    return k;\r\n}<\/pre>\n
The code is self explanatory with the detail comments. Compile and upload the code into Arduino board and watch the result.<\/p>\n
\"lcd-keypad-13\"<\/a>Once the code is successfully compiled and upload into Arduino board, you should see the display as above shown.<\/p>\n
Parts Used in this Tutorial<\/span><\/h3>\n