Monitorcontrol: Automatically adjust brightness

[funbben]

It would be nice to be able to use the mac "auto adjust brightness" to set the brightness of external display automatically

https://i.stack.imgur.com/eYQuM.png

[the0neyouseek]

Hi @funbben,

Thats a great idea but would be quite difficult to implement because this feature depends on the ambient light sensor (located next to the camera) of your Macbook Pro/iMac and not all external screen have one.

I'll leave this issue open for now to see if anyone has a better idea about tackling this.

PS. We could, for exemple use the one present on your MBP/iMac if we have one, but I'm not sure how. I'll look into it.

[funbben]

The idea was to use mac internal sensor and apply same setting as Mac display

[retrography]

I think the idea @funbben described is actually very interesting. The only thing is: One will have to check first whether the computer is a laptop and whether it is running the clamshell mode or not.

[rowanalex123]

Hammerspoon provides the lux reading from the ambient light sensor on Macs. Apprently they use the raw value from the sensor and run Mozilla's algorithm to convert it to lux

[retrography]

@rowanalex123 Have you actually tried that? The function only returns an error for me -- which is a -1 (on MacBook Pro 2016).

[rowanalex123]

I tried it now. It returns -1 for me as well on a 2017 Mac pro

[arnoappenzeller]

I would really like this idea with using the Mac Books ambient sensor.

Has someone already tried this code for reading the data?

I think I'm gonna play around a bit with it soon

[the0neyouseek]

Hi, first of all sorry for the late response.
I'll try to work on this feature this week-end.

[jcastro]

Just something that might be of interest. The new LG 2019 Ultrafine 5k is finally using the light sensor (see https://twitter.com/jonatan/status/1167163794281455616) so maybe there's a chance to use that information to automatically change others' display brightness (probably with a configurable offset for the value)

[jcastro]

Another interesting fact, looks like now even the older LG Ultrafine 5k that didn't have the auto-brightness working now it's enabled if you are on Catalina.

[rshev]

Just found this app, mainly because I'd like to have different brightness during the day and in the evenings, and immediately thought of this idea. Has anyone had any luck reading ambient light values? I might help, I do swift for a living.

[dmatora]

@the0neyouseek

1. There is an open source console app that allows automatically changing brightness on old UltraFine 4K/5K monitors that don't have ambient light support built into maOS.
   https://github.com/qvacua/ultrafine-auto-brightness
   I own old UltraFine 4K monitor and would love to see it's ambient light sensor support in MonitorControl

1. It would also be awesome to trigger dark theme based on ambient light sensor value, like this (not very user friendly) open source app does http://codes.kary.us/health/starlight

2. And finally there is an open source app that allows to use Macbook sensor to adjust brightness of external monitor https://github.com/OCJvanDijk/Brightness-Sync it's code can be used for those who use regular monitors with no ambient light sensor