Turning cheap USB numeric keyboard into 4x4 drum pad controller for Ableton with LuaMacros

luamacros_numpad_into_drumpad_for_ableton.lua

-- assign logical name to macro keyboard
lmc_assign_keyboard('DRUMPADCONTROLLER');

-- alternatively, set the logical name to a specific keyboard
-- lmc_device_set_name('DRUMPADCONTROLLER', '295601EB')

-- list all devices
lmc_print_devices();

--keymapping:

map = {};

map[97] = 'a';    -- numeric keyboard '1'         <= ableton 'C'
map[98] = 'w';    -- numeric keyboard '2'         <= ableton 'C#'
map[99] = 's';    -- numeric keyboard '3'         <= ableton 'D'
map[13] = 'e';    -- numeric keyboard 'ENTER'     <= ableton 'D#'
                  
map[100] = 'd';   -- numeric keyboard '4'         <= ableton 'E'
map[101] = 'f';   -- numeric keyboard '5'         <= ableton 'F'
map[102] = 't';   -- numeric keyboard '6'         <= ableton 'F#'
map[8] = 'g';     -- numeric keyboard 'BACKSPACE' <= ableton 'G'
                  
map[103] = 'y';   -- numeric keyboard '7'         <= ableton 'G#'
map[104] = 'h';   -- numeric keyboard '8'         <= ableton 'A'
map[105] = 'u';   -- numeric keyboard '9'         <= ableton 'A#'
map[107] = 'j';   -- numeric keyboard '+'         <= ableton 'B'
                  
map[144] = 'k';   -- numeric keyboard 'NUMLOCK'   <= ableton 'C 8a+'
map[111] = 'o';   -- numeric keyboard '/'         <= ableton 'C# 8a+'
map[106] = 'l';   -- numeric keyboard '*'         <= ableton 'D  8a+'
-- map[109] = ''; -- numeric keyboard '-'         <= not assigned

map[96] = 'z';    -- numeric keyboard '0'         <= ableton 'Octave UP'
map[48] = 'x';    -- numeric keyboard '000'       <= ableton 'Octave DOWN'
map[110] = ' ';   -- numeric keyboard '.'         <= ableton 'Play/Stop'

-- assigning the same values for the NUMLOCK OFF keycodes of the same keys:

map[45] = map[96];
map[46] = map[110];
map[35] = map[97];
map[40] = map[98];
map[34] = map[99];
map[37] = map[100];
map[12] = map[101];
map[39] = map[102];
map[36] = map[103];
map[38] = map[104];
map[33] = map[105];

-- initializing the 't' tables with zeros

t = {};

for i = 0, 300
do
  t[i] = 0;
end

-- initializing triple zero key workaround counter

tripleZeroCounter = 0;

-- defining callback for whole device
lmc_set_handler('DRUMPADCONTROLLER', function(button, direction)

  -- key pressed and was not pressed before
  if(direction == 1 and t[button] == 0)
  then

    target=map[button];
    
    -- NUMLOCK workaround (send another NUMLOCK to toggle back to original state)
    if (button == 144) 
    then
      lmc_send_input(144, 0, 2); -- press NUMLOCK
      lmc_send_input(144, 0, 0); -- release NUMLOCK
      -- print('reversing NUMLOCK to original state');
    end

    -- triple zero workaround (use first and ignore other two)
    if (button == 48)
    then

      tripleZeroCounter = tripleZeroCounter + 1;
      
      if (tripleZeroCounter == 3)
      then
        tripleZeroCounter = 0;
      end

      if (tripleZeroCounter ~= 1)
      then
        return;
      end
      
    end

    if map[button]
    then

      lmc_send_keys(target); -- press the key

      print('Pressed button ' .. button .. ' and send key "' .. target .. '"');

    else

      print('Pressed button ' .. button .. ' and nothing defined to be done');

    end

    t[button] = 1;

  elseif (direction == 0)
  then
    
    print('Released button ' .. button);
    t[button] = 0;

  else

    -- in this project just do nothing in this case
    -- print('Still pressed and repeating button ' .. button);

  end

end)

This code is part of this post in LuaMacros forum:

[Turning cheap USB numeric keyboard into 4x4 drum pad controller for Ableton] (http://www.hidmacros.eu/forum/viewtopic.php?f=12&t=529)