MultitapKeypad Arduino Library Documentation

Overview

This library allows interfacing between an Arduino board with matrix 4 x 3 phone's keypad as well as matrix 4 x 4 keypad. It can indicates the key states such as key down, repeatedly key tap, key press and hold, multiple key down, and key release.

Public Constructor

For the matrix 4 x 3 phone's keypad which consist of four rows and three columns, defines each row and column as constructor arguments in following order:

MultitapKeypad(row_0, row_1, row_2, row_3, col_0, col_1, col_2)

Whereas for the matrix 4 x 4 keypad simply defined fourth column (col_3) as last argument of constructor below:

MultitapKeypad(row_0, row_1, row_2, row_3, col_0, col_1, col_2, col_3)

The determination of the order of each row and column refer to Fig. 1. First row as R0, second row as R1, and so on. Similarly first column as C0, second column as C1, and so forth.

The arguments row_0...row_3 and col_0...col_3 are any valid Arduino pins number which connected to related keypad rows and columns number.

Figure 1. Matrix Keypad Configuration

Public Methods

• getKey()

  Returns Key object which consist of:

  • Key.character

    It is a byte type number which correspond with active key i.e.:

    • NO_KEY = 0
    • KEY_1 = '1'
    • KEY_2 = '2'
    • KEY_3 = '3'
    • KEY_A = 'A'
    • KEY_4 = '4'
    • KEY_5 = '5'
    • KEY_6 = '6'
    • KEY_B = 'B'
    • KEY_7 = '7'
    • KEY_8 = '8'
    • KEY_9 = '9'
    • KEY_C = 'C'
    • KEY_ASTERISK = '*'
    • KEY_0 = '0'
    • KEY_NUMBER_SIGN = '#'
    • KEY_D** = 'D'

  • Key.state

    It is a custom KEY_STATE number indicates of key event which consist of:

    • KEY_DOWN

      Indicates there is a key was pressed.

    • MULTI_TAP

      Indicates that the active key is identical with previous pressed key for less than one second.

    • LONG_TAP

      Indicates there is a key was pressed and held for at least one second.

    • MULTI_KEY_DOWN

      Indicates there are multiple keys were pressed.

    • KEY_UP

      Indicates there is a key was released.

  • Key.tapCounter

    It is a byte type number count from 0 to 255, indicates the number of multi-tap key minus one. One indicates second tap, two as third tap, and so forth. Max 256 custom multi-tap characters can be accessed.

  • Key.code

    It is a byte type number as scan code of current active key which represented NO_KEY, KEY_0...KEY_9, KEY_ASTERISK, KEY_NUMBER_SIGN, KEY_A...KEY_D. If the number is not one of previously mentioned means MULTI_KEY_DOWN event was happened.

  • Key.lastCode

    It is a byte type number as scan code of just before current active key.

  • Key.beforeLastCode

    It is also a byte type number as scan code of just before last active key.

• resetTapCounter()

  Reset multi-tap counter to zero for user desired multi-tap characters array.

• attachFunction(userFunction)

  While user calling getKey() method the process will returned if the new key event reached. To prevent user from loosing processor resources for other processing, this method offers to attach a user function to callback while waiting key state changed.

  For example:

  // creates keypad as MultitapKeypad object
  MultitapKeypad keypad(4, 5, 6, 7, 8, 9, 10, 11);
  // creates key as Key object
  Key key;
  
  void setup() {
    // attaches a user function to callback while waiting key state changed
    keypad.attachFunction(userFunction);
    // put your setup code here, to run once:
  }
  
  void loop() {
    // get key object
    key = keypad.getKey();
    // put your main code here, to run repeatedly:
  }
  
  void userFunction(void) {
    // do other process while waiting between two key events (key state changed)
  }
  

Examples

This library provides with following examples:

• Key States Test on Serial Monitor

  This example displays every key states on Serial Monitor, also the tapCounter value. To run the test, open Serial Monitor, don't forget to set the baud rate at [ 9600 baud ] and set the line ending to [ Newline ]. Hardware wiring can be followed on Fig. 2.

Figure 2. Matrix Keypad Wiring

• Key States Test on LCD 1602

  Displays every key states on LCD 1602, also the tapCounter value. Hardware wiring can be followed on Fig. 2. and Fig. 3.

Figure 3. LCD 1602 Wiring

• Typewriting Demo on LCD 1602

  This example demonstrates the typewriting style just like on old Nokia phone. Fig. 4. and Fig. 5. illustrate all available characters which can be accessed. Character in the parentheses accessed through long-tap or hold the relevant key for at least one second. Hardware wiring also can be followed on Fig. 2. and Fig. 3.

Figure 4. Keypad Style in Alphabet Mode

Figure 5. Keypad Style in Numeric Mode

• Input String on LCD 1602

  If the previous example demonstrates the typewriting style just like on old Nokia phone, this example captures the entered string from the keypad into a string buffer and displays them to Serial Monitor. Fig. 6. and Fig. 7. illustrate all available characters which can be accessed. Character in the parentheses accessed through long-tap or hold the relevant key for at least one second. Hardware wiring also can be followed on Fig. 2. and Fig. 3.

Figure 6. Keypad Style in Alphabet Mode

Figure 7. Keypad Style in Numeric Mode

 

 

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Created by ZulNs

@Gorontalo, Indonesia, 15 April 2017

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