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GKOS Keypad

15 April 2010

You can learn more details about GKOS for Arduino here.

What it does

If you are planning to build a stand-alone system where a small but full-featured keyboard is needed, this simple solution could be useful for you.

With the 6 GKOS keys, directly connected to Arduino I/O pins, it is possible to type any text and enter most functions found on the PC keyboard (Alt, Ctrl, Tab...).


Gkos keypad wiring

Other I/O pins can also be used.


  • Gkos library

  • Function gkos.entry(); will return with the character typed.

  • The pins used are defined at the initialisation by Gkos gkos(14, 15, 16, 17, 18, 19);

There are sample sketches showing how to use the library. One sketch uses an LCD to display the text typed, one just indicates the keypad operation by the pin 13 LED on the Arduino board. The third sketch uses the IDE Serial Monitor to show the text typed.

In order to use the software library and example sketches with Arduino 1.0+, line 10 of Gkos.cpp and Gkos.h should be updated from WProgram.h to Arduino.h, and instances of Serial.print(x, BYTE) should be changed to Serial.write( byte (x) ).

How to type

GKOS Alphabet

The GKOS Alphabet.

Letters G, K, O, S and W require two keys, and they also function as modifiers (shifts) changing the characters on other keys.

Pressing all 6 keys down toggles between numbers and letters. You get backspace by pressing the 3 keys on the left, and space by pressing the 3 keys on the right. The full character set can be found here.