LightPanel
Portable LED Light Panel
Limitations
LightPanel has some limitations controlling screen brightness on a Mac:
LightPanel only controls the brightness of the primary display in a multi-monitor setup. Given LightPanel is intended to be used on a mobile device this is unlikely to be an issue in practice.
LightPanel can only control the brightness of a monitor if the Mac itself can control it's brightness (eg via the Display pane of System Preferences).
LightPanel cannot control screen brightness on an Apple Silicon Mac. This is because Apple have not yet provided a public API that works on Apple Silicon. The brightness controls are disabled in this case.
Remote Control has the following limitations:
Remote Control uses bluetooth and/or Wifi to connect devices, so each device must have these enabled and be in range (and Airplane mode turned off).
Only Wifi and Ethernet connectivity are supported on Mac & Apple TV.
LightPanel on AppleTV has the following restrictions:
Apple TV cannot control the brightness of the TV and the LightPanel brightness controls are therefore not shown. Please use the TV controls to adjust brightness if required.
tvOS has a simpler user interface than iOS and macOS:
No sliders, so LightPanel on AppleTV uses up/down buttons to replace the functionality of the Brightness, Temperature and Hue sliders.
No menus, so there are no long-press button menus in LightPanel on Apple TV. Long-press on a colour patch sets the patch to the current colour, rather than showing a menu.
There are no Help, Contact or Share functions.
There are no scanning grid or masks, as these functions don't make sense on a TV.