This is script to auto on/off a Logitech light when the webcam is on/off in Mac. It requires hidapitester

litra-auto-on.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
   <key>Label</key>
   <string>litra-auto-on</string>
   <key>ProgramArguments</key>
   <array><string>/Library/LaunchDaemons/litra-auto-on.sh</string></array>
   <key>RunAtLoad</key>
   <true/>
</dict>
</plist>

litra-auto-on.sh

#! /bin/bash

# Download both files and https://github.com/todbot/hidapitester to /Library/LaunchDaemons/
# Execute the following commands to launch it on login
# sudo chown root:wheel /Library/LaunchDaemons/litra-auto-on.plist
# sudo chmod o-w /Library/LaunchDaemons/litra-auto-on.plist
# sudo launchctl load -w /Library/LaunchDaemons/litra-auto-on.plist
# For test it:
# launchctl start litra-auto-on
# tail -f /var/log/system.log

# Use 046D/C900 for older models
model="046D/C901"
# Change to your own path
hidapitester="/Library/LaunchDaemons/hidapitester"


log stream --predicate 'subsystem contains "com.apple.UVCExtension" and composedMessage contains "Post PowerLog"' | while read LOGLINE
do
  [[ "${LOGLINE}" == *"On;"* ]] && eval "$hidapitester --vidpid $model --open --length 20 --send-output 0x11,0xff,0x04,0x1c,0x01"
  [[ "${LOGLINE}" == *"Off;"* ]] && eval "$hidapitester --vidpid $model --open --length 20 --send-output 0x11,0xff,0x04,0x1c"
done

I enjoyed the feature in G-Hub but unfortunately G-Hub also caused lots of problems with my Yeti Mic. https://www.reddit.com/r/LogitechG/comments/oypw43/logitech_ghub_update_breaks_blue_yeti_mic/

The version in https://gist.github.com/antonmry/8bf2d07db75df538c385bfa1cd6d5cf2?permalink_comment_id=4723193#gistcomment-4723193 worked well for me, except that it would turn on whenever my phone came near my computer (i.e. the continuity camera logs triggered the light to turn on). This was the script I have that is working well. Note the addition of bundleNames:

model="046D/C900"
hidapitester="/Library/LaunchDaemons/hidapitester"

log stream --predicate 'eventMessage contains[c] "cameras changed to "' | while read LOGLINE;

do
  # ON
  [[ "${LOGLINE}" == *"changed to [ControlCenterApp.VideoCamera"*"bundleNames"* ]] && eval "$hidapitester --vidpid $model --open --length 20 --send-output 0x11,0xff,0x04,0x1c,0x01";
  # OFF
  [[ "${LOGLINE}" == *"changed to [:]"* ]] && eval "$hidapitester --vidpid $model --open --length 20 --send-output 0x11,0xff,0x04,0x1c";
done