Windows KB Switcher Thing

This program will run one of a number of different, user-specified commands depending on which keyboard most recently emitted a keypress. It will run this command once for each series of keypresses made with that keyboard.

The program runs in the system tray, and can be closed by choosing Exit from its context menu.

Why does this exist

I have a Logitech K400 Plus wireless keyboard by my TV, which is hooked up to my desktop in another room. I would like my computer to automatically switch my audio device and display output to the TV when I type on my K400 Plus, and I'd like everything switched back when I type with the keyboard at my desk.

Basic usage

The application will attempt to read configuration from a file in the working directory with the names config.json, config.toml, and config.yaml. A configuration will consist of a list of commands, where each command has three keys - keyboard, cmd, and args. keyboard specifies which keyboard the rule applies to - when a key is pressed, each rule is checked, and the first rule that matches a keyboard is used. Keyboards are matched if their device name contains the text in the keyboard field of a command. On a match, the binary pointed to by the cmd field of the command is run with the arguments specified in the args field.

Note that an empty string for the keyboard field works as a default rule, and will apply to all keyboards not previously specified. A default rule like this should be the last one in the config file.

You can find device names in the Windows Device Manager, under the Device instance path property.

For example

Consider this configuration

[[commands]]
keyboard = "VID_046D&PID_C52B"
cmd = "cmd.exe"
args = [ "/c", "resources\\tv.bat" ]

[[commands]]
keyboard = ""
cmd = "cmd.exe"
args = [ "/c", "resources\\normal.bat" ]

Let's look at the first rule. VID_046D&PID_C52B is the vendor id and product id of the wireless receiver of the aforementioned Logitech K400 Plus. That means that whenever I type on that keyboard, this is the rule that will apply, as this string will appear in the product name. So when I type on my K400 Plus and it is not the most recent keyboard I've used, it will run cmd.exe with the arguments /c resources\\tv.bat, which could, say, set my audio device to the TV and enable video output to it in my graphics settings.

The other rule has an empty string for the keyboard field. This means that whenever I type on a different keyboard, and that keyboard is not the most recent keyboard I've typed on, it will run the command specified by this rule. So when I type with the keyboard plugged into my desktop directly, or any other keyboard besides the K400 Plus, it will run cmd.exe with the arguments /c resources\\normal.bat, which could, say, set my audio device to my gaming headset and turn off video output to my TV.