LettersKeypad

A simple arduino alphanumeric (A-Z,a-z,0-9) 4x3 Matrix keypad.

dependency:
Arduino Keypad: https://github.com/Chris--A/Keypad

1. initialize keypad:

byte col[] = {8, 7, 6};
byte row[] = {12, 11, 10, 9};

LettersKeypad keypad(row, col);

2. Set key release interval:

keypad.setUpdateTime(2000); // key will be print after 2sec