4 x 4 Keypad

BlocklyProp reference for KEYPAD blocks

For Propeller Activity Board WX, FLiP and Other board types. Not available for Badge or Scribbler Robot board types.

These blocks are specifically for the 4 x 4 Matrix Membrane Keypad (#27899) sold by Parallax.

New to this sensor? Click here to see an example schematic and quick Blockly program to help you get started.

4x4 Keypad Initialize

The 4x4 Keypad Initialize block defines the connections between the Keypad's ribbon cable and the Propeller microcontroller's I/O pins. I/O pin availability will vary by board type.

If you have defined a constant using the constant define block, the constant will show up in all of the pin menus and can be selected instead of a numbered pin:

If you forget to use this block in your program, a triangle warning icon will appear on other 4 x 4 keypad blocks as a reminder.

With the keypad facing you, start matching from the leftmost pin to the rightmost pin. The four rightmost pins MUST be connected to pull-down resistors; use 1 k-ohm to 100 k-ohm resistors for this.

4x4 Keypad Read

The 4x4 Keypad read block provides a number value for the key pressed. 

  • 0-9 read as values 0 to 9
  • A reads as 65 (ASCII character 'A')
  • B reads as 66 (ASCII character 'B')
  • C reads as 67 (ASCII character 'C')
  • D reads as 68 (ASCII character 'D')
  • # (pound sign) reads as 35 (ASCII character '#')
  • * (asterisk) reads as 42 (ASCII character '*')
  • No button pressed reads as -1.