On-air Indicator

You're muted, dude!

Requirements

• ESP32 hardware of some kind. This project was written for an M5Stack Atom development platform.
• VSCode + Platform.io installed and configured
• A computer running MacOS
• skhd (typically installed via homebrew)

Setup

1. Copy src/config.h.sample to src/config.h and edit the WiFi connection information there to match your network.
2. Build the project and upload it to your device.
3. Edit toggle_input_level.scpt to set the location of current_volume.txt to the project location on your disk.
4. Run ./background_input_monitor.sh & to background it. Or run it without the ampersand if you want it to run in the foreground.
5. Edit your ~/.skhdrc file to include a keyboard shortcut to run the input-level toggle as described below and run brew services restart skhd to reload the configuration.
6. Enjoy your glowing LED.

How it works

The ESP32 is running a web server with two endpoints and a default networking configuration that will register a hostname on your network as on-air-esp32.lan. Two endpoints are available for updating your mute status: * /on-air: Green light, you're unmuted! * /off-air: Red light, you're muted!

The background_input_monitor.sh script continuously monitors the volume level by polling the MacOS system preferences via applescript. It saves the volume level to a file if that level is over '0'. This script needs to be running in the background before you run the toggle. If the current_volume.txt file is missing or the location is incorrectly defined in the toggle_input_level.scpt script, that script will fail to run.

The toggle_input_level.scpt script is an applescript that toggles the input volume level by reading the contents of the file created by background_input_monitor.sh.

The toggle_input_level.scpt script is triggered by a keyboard shortcut defined in your skhd preferences. Example using the left-hand modifiers + the 'm' key: lshift + lalt + lctrl + lcmd - m : osascript /Users/tony/projects/on-air-sign/toggle_input_level.scpt

This will globally mute your microphone and update the LED on your microcontroller, independent of the application currently using your mic. The downside is your applications will no longer indicate your mute status but the upside is if this breaks horribly you won't have to talk in meetings anymore.