SetLEDs Karabiner for Mac OS X

This is for those who use Karabiner and want the Num Lock key on their keypad to not only remap the keys (which Karabiner can do) but also set the Num Lock led correctly on the keyboard (which, as of this writing, Karabiner can't do).

Overview

To get this to work there is a script called setleds_karabiner.sh that can be run from Karabiner (or the command line for that matter). This script works by first selecting a profile in Karabiner that does not include any keyboards - you must define this yourself. Then it uses setleds to set the numlock led to the desired state. Then it sets the Karabiner profile back to whatever was active when you ran the shell script.

The script is fairly bullet-proof, e.g

• It should work even if there are spaces in things like path names
• If you run it with the wrong number of arguments it prints out a usage message
• It checks that the 'no keyboard' profile you want to use actually exists before it does anything
• It will keep trying the setleds command until it either works or 2s have passed (there is a delay between when Karabiner returns from the set profile command and when it actually takes itself out of the way).

Installation

Download the setleds_karabiner.zip from releases. It contains:

• setleds binary
• setleds_karabiner.sh
• enable_numlock_toggle.json
• numpad_keys.json

In no particular order:

• Create a folder called bin directly under your home directory and put both the setleds binary and setleds_karabiner.sh in it. If you don't do this you will have to edit enable_numlock_toggle.json and if setleds and setleds_karabiner.sh are in different directories, you will have to edit the shell script too.
• Create a profile in Karabiner that does not contain any devices. Call it No keyboard. If you call it something else, you will have to edit enable_numlock_toggle.json to pass that profile name as a second argument to setleds_karabiner.sh.
• Load enable_numlock_toggle.json as a complex rule in Karabiner. If you have already loaded 'Enable Num Lock Toggle', replace it with enable_numlock_toggle.json.
• Optionally load numpad_keys.json as a complex rule - this is what remaps the keys. If you already have 'Numpad keys' installed, you can just use that. I only provide it so this zip is a one-stop-shop.
• Read the Notes section below before you go hammering the numlock key - it will help avoid any issues.

Notes

• If you haven't run setleds before, you will need to get the Mac to allow it. The easiest way is to run it from the finder by selecting 'Open' on the context menu. You should be given the option of adding it to the safe list.
• The first time you hit the numlock key, assuming everything works, you should see a popup telling you you need to add karabiner_console_user_server to the list of 'allowed applications' in the 'Input Monitoring' part of System Settings. It won't work if you don't do this. You can also just got to Input Monitoring and add it yourself.

Troubleshooting

If it doesn't work, look in the logs section of Karabiner