SetLEDs for Mac OS X + Monitor Mode

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Original project: https://github.com/damieng/setledsmac

Keyboard	High Sierra	Mojave	Catalina
Cooler Master MasterKeys Pro M	✅	✅	✅

This command-line tool lets you set your keyboard LEDs. This is especially useful if you have a back-lit keyboard and don't want scroll lock, number lock or caps lock to remain unlit.

Unlike many other solutions, this does not require you to install any third party utilities to manipulate or capture keystrokes. The utility built from this project runs standalone as a LaunchDaemon at login time and handles numlock, scrlck, and capslock LEDs.

Note

Setting the LED on or off does not affect the behavior of that key so even though the led for caps lock will be on caps lock itself will still be off. Tapping the key will cause the lock to come on but the LED will already be on so it will not appear to change. Tapping it again will turn it off (and cause the LED to turn off).

Accessibility Permission on Mojave and Up

It is required that setledsmac is allowed accessibility functions for it to operate on OSX Mojave and up. Once you download the binary (or compile it yourself), place it on the location you want it to run and then open System Preferences -> Security & Privacy -> Find the "Accesibility" section. Unlock the pane by clicking on the padlock symbol, then press the + button to open a file browser. Now navigate to the location and select your setleds binary. Lock the pane by pressing the padlock icon again.

Usage

You can set LEDs by simply specifing either a - to turn an LED off, a + to turn an LED on or a ^ to toggle an LED followed by either the word scroll (for scroll lock), num (for numeric lock) or caps (for caps lock). e.g.

setleds -caps +scroll ^num

Name matching

By default setledsmac will set the modifiers for all keyboards attached to your Mac. If you wish to limit it you can use the -name parameter followed by a wildcard. Note that if you want to use a space then specify the wildcard in quotes, e.g.

setleds +scroll -name "Apple Key*"

Verbose mode

setledsmac will report what keys it changed for each keyboard. This is sometimes different per keyboard if either the keyboard does not have that modifier (e.g. Apple keyboards do not have scroll lock) or if the keyboard already had that LED on.

Specifying -v on the command line will cause setledsmac to report the state of the other unchanged modifier keys on that keyboard too. Note that you will not see the state of modifiers that keyboard does not have.

Monitor mode

Use the "monitor" sub command to run continuously and toggle LEDs on keypress. This allows running the binary as a daemon at startup for seamless functionality. This is useful if you have a keyboard incompatible with OSX that require frequent toggling of numlock keys (i.e., TKL CoolerMaster CM keyboards)

Usage:

$ setleds monitor

Automatic Startup

You may use the bundled LaunchDaemon configuration to launch setleds at startup. Note

# Build the binary from the sources or download the pre-built release from the github repo.
# Copy it to a specific path in your system (ie: /Users/jane/bin/setleds)
# IMPORTANT: Don't forget to configure accessibility access (see above)

# Use the bundled script to setup the LaunchDaemon
$ sudo ./install.sh /Users/jane/bin/setleds

Restart the mac and now you should have numlock toggling functionality without extra action, just like a normal keyboard!