This describes how to create a hot mic icon in the Touch Bar, like this: https://twitter.com/youfoundryan/status/1238507646677700608
- Install BetterTouchTool (https://folivora.ai/)
- Create a new Touch Bar widget of type "Apple Script/Javascript Widget". You don't need a trigger.
- Paste the contents of mic_state.scpt into the script box.
- Set the "Alternate Color Regex" to "off".
- Switch to the "common" widget settings pane. Set the button background color to red. Set the "Select Button Icon" to the mic and the "Alternate Button Icon" to the mic with a line through it.
- Check "show only icon, no text"
I also assigned a FN key on my external keyboard to toggle the mic: