LCD Button Shield V2 for Arduino by Sparkfun

LCD Button Shield

TheLCD 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: 

/*
  LiquidCrystal Using Sparkfun LCD Button shield
  https://www.sparkfun.com/products/13293
  NOTE:   This uses different hook up than what the examples in the arduino library use.  see The circuit:
 * LCD RS pin to digital pin 12  (8 for shield)
 * LCD Enable pin to digital pin 11 (9 for shield)
 * LCD D4 pin to digital pin 5   (D4)
 * LCD D5 pin to digital pin 4   (D5 for shield)
 * LCD D6 pin to digital pin 3   (D6 for shield)
 * LCD D7 pin to digital pin 2   (D7 for shield)
 * LCD R/W pin to ground
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)
 */

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
// for the sparkfun shield
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

void setup()
{
    // set up the LCD's number of columns and rows:
    lcd.begin(16, 2);
    Serial.begin(9600);  //for debugging

}

char* buttons[] = {"Left", "Up", "Down", "Right", "Select", "Undefined"};

#define LEFT_BUTTON     0
#define UP_BUTTON       1
#define DN_BUTTON       2
#define RIGHT_BUTTON    3
#define SEL_BUTTON      4
#define UNDEFINED       5

int buttonindex;

void loop()
{
    int buttonValue = 1023;
    lcd.clear();
    lcd.print("Press Any Button");

    while (buttonValue > 1015) 
    {
        buttonValue = analogRead(A0);
        Serial.println(buttonValue);
    }

    if (buttonValue > 845 && buttonValue < 865)  // left button
    {
        buttonindex = LEFT_BUTTON;
    }
    else if (buttonValue > 915 && buttonValue < 949)  // UP button
    {
        buttonindex = UP_BUTTON;
    }
    else if (buttonValue > 895 && buttonValue < 910) // down button
    {
        buttonindex = DN_BUTTON;
    }
    else if (buttonValue > 810 && buttonValue < 820) // right button
    {
        buttonindex = RIGHT_BUTTON;
    }
    else if (buttonValue > 605 && buttonValue < 620) // select button
    {
        buttonindex = SEL_BUTTON;
    }
    else buttonindex = UNDEFINED;
    lcd.clear();
    lcd.print(buttons[buttonindex]);
    lcd.print("  pressed");
    // wait for key to be releasted

    while (buttonValue < 1000) 
    {
        buttonValue = analogRead(A0);
    };  // sit in this loop till key unpressed

}

Click Here to pick up one of these shields for your next project

David Riewe

David Riewe

Published

Wed 30 December 2015

Learn more about David Riewe on the Featured Hackers Page.

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