LCD Button Shield V2 for Arduino by Sparkfun

The LCD Button Shield from Sparkfun Electronics provides a 16x2 LCD screens along 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.

The LCD Button Shield V2 works perfectly in 4-bit mode with the “LiquidCrystal” library found in the Arduino IDE.

 NOTE: The pin hook up used by this shield is different from the samples in the library.  

  The circuit used in Arduino library is usually wired as:
 * LCD RS pin to digital pin 12
 * LCD Enable pin to digital pin 11
 * LCD D4 pin to digital pin 5
 * LCD D5 pin to digital pin 4
 * LCD D6 pin to digital pin 3
 * LCD D7 pin to digital pin 2
 * LCD R/W pin to ground
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)

   The circuit on the shield is  wired as:
 * LCD RS pin to digital pin 8
 * LCD Enable pin to digital pin 9
 * LCD D4 pin to digital pin 4
 * LCD D5 pin to digital pin 5
 * LCD D6 pin to digital pin 6
 * LCD D7 pin to digital pin 7
 * LCD R/W pin to ground
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)

The keypad consisting of 5 keys are arranged in a voltage ladder connected to A0.  Each key press produces a unique value ranging from 0 to 1023.  Pressing multiple keys together will generate unique values as well.  When I wrote the demo program to test the shield I would use the serial monitor to see the analogue values read for each key then I adjusted my code to accept values ranging within +- 10 of the value read.

Here is a short video of the shield with the demo code below:

Here is a link to pick up one of these shields for your next project
https://www.sparkfun.com/products/13293