MonitorControl: Control external monitor brightness and volume on your Mac
github.com
github.com
I have a script hacked together to fetch the internal display's brightness once a minute and apply it, with a scaling factor, to the external, so that they're both effectively controlled by the laptop's ambient light sensor. It's really nice for working in a room with lots of windows.
A more batteries-included alternative, which appears to also provide brightness sync, is Lunar (https://lunar.fyi/). I haven't had a chance to try it, but the Github repo makes it look pretty solid.
Funny how similar thought processes can be sometimes. I’m now up to motorising my blinds so that the light sensor also controls the blinds to keep the room at the same light level through the day.
I miss the roof deck at work. This time of year, weather and meeting schedule permitting, I'd typically spend somewhere between four and sixteen hours a week up there, enjoying the heat and watching ospreys, gulls, and the occasional peregrine while I waited for builds or test runs or whatever.
I think like many folks lately, I seem to have developed a touch of agoraphobia this year. But I need to at least be able to see outside, or I start to forget I exist.
[1]: https://storage.googleapis.com/ta-share/2020-07-10.11.01.02....
I've had a lot of feedback on it and users really helped me to fix most of the use cases so please give it a try. It has a lot of options to make it work just the way you want.
And if it doesn't, feel free to send me feedback. I'm still developing new features for it like weather aware adaptive brightness (for less brightness on those cloudy days), an external USB light sensor (for Mac Minis, clamshell mode Macbooks or even Hackintoshes) and a new curve fitting algorithm to better adapt the 0-100 curve when you adjust the brightness manually.
It’s possible that in High Sierra you are missing the Swift 5 runtime. You can find details about this in the troubleshooting section of the GitHub readme.
Here is the link where you can download an installer for that: https://support.apple.com/kb/DL1998?locale=en_US
I've switched over to using Lunar as of this morning, following the runtime install. Unfortunately, it looks like today's going to be cloudy straight through, so I don't know that I'll get the best opportunity to see the app strut its stuff right away. That said, the UX has been very solid thus far, and I like the extensive configurability even if I have no intention of using more than about 5% of it.
Strong recommend, and definitely worth a coffee!
ioreg -c AppleBacklightDisplay | grep brightness | cut -d= -f2- | perl -pe's@=@:@g'
MonitorControl wasn't able to control my Brightness, it just set it to lowest level. This made me realise that there was some support to DDC, I tried trouble shooting using ddctl which was able to set the values, but not poll it.
Finally tried Lunar (https://lunar.fyi/) and it works like a charm. It's more of a set it and forget approach and has a unique UI.
No one else in my house cares though.
How do you know if your monitor, television, or project supports this? And does it depend on the connector used? (HDMI, DisplayPort, VGA?)
Does this work for most display peripherals, only newest/expensive ones, or something in between?
More specifically it is called MCCS: https://milek7.pl/ddcbacklight/mccs.pdf
> Here’s that rare Steve Jobs story, one that’s never been told, about the company that got away. Jobs had been tracking a young software developer named Drew Houston, who blasted his way onto Apple’s radar screen when he reverse-engineered Apple’s file system so that his startup’s logo, an unfolding box, appeared elegantly tucked inside. Not even an Apple SWAT team had been able to do that.
> Rajiv Eranki (early employee, no longer at Dropbox) did much of the reverse-engineering required to get the our file overlay icons onto files in the Finder, and also to get us into context menus.
https://www.forbes.com/sites/victoriabarret/2011/10/18/dropb...
https://www.quora.com/Many-articles-about-Drew-Houston-say-t...
They probably also typically have some flash memory, so perhaps one could permanently reprogram a monitor after the exploit?
The crazy thing is that computers send +5V over the DDC bus to the monitor so that they are able to read data even if the monitor is powered off and not connected to the mains! So, simply connecting something to the computer's display port could be enough.
Saved me from buying a new monitor or something silly like getting an iMac. Seriously weird why they don't just support DDD/CI natively.
The main reason why I think this wouldn't work is because in the display properties there's no brightness slider for non Apple external displays. There is one for Apple displays.
insmod ddcci_bl.ko
modprobe i2c-dev
echo ddcci_bl 0x37 > /sys/bus/i2c/devices/i2c-2/new_device (replace i2c-2 with bus number for your monitor)This allows controlling the screen brightness from the usual places (gnome power menu thingy or via light for the i3 crowd). See the Arch Linux Wiki for more info [0].
Arch : ddcci-driver-linux-dkms (aur)
Ubuntu : ddcci-dkms
[0] https://wiki.archlinux.org/index.php/Backlight#External_moni...
On resume from suspend the monitor always dims down to some ridiculously low setting, and without `ddcutil` I'd have to manually adjust the brightness via hardware toggle. As a workaround for the limitation of the monitor I just have a bash script that invokes `ddcutil` on resume from suspend - wonderful :)
This little menubar control looks like just what I wanted.
Edit: Yes it works great! On my LG24UD58. Perfect! Unfortunately it doesn't seem to work with my Eizo L568 but that's ancient. And I think it had some special USB-based control method. But really glad to be able to get rid of the LG software now.
PS: You have to enable the contrast with a tickbox, otherwise that slider is not shown.
The iMac light sensor controls the brightness of both monitors automatically. You can even insert a fixed offset to match the absolute brightness of both monitors.
But my Mac has no brightness sensor (it's a mini). I use the screen with my PC and a raspberry pi as well so I couldn't use an iMac, though I have one at the office (if I ever go back there...). It's really a shame they got rid of the target display function, this would have been perfect :(
I didn't even know it was a thing and thought there was a special chip in the Apple screens to be able to control your screen from your computer.
I'm the developer of Lunar so feel free to ask any questions about it.
https://www.stackednotion.com/blog/2019/05/07/automatically-...
I have a laptop with a Ryzen 3 and a 1660ti, so it might be the Nvidia graphics that is enabling this.
[0] https://smile.amazon.com/Cable-Matters-Multiport-DisplayPort...
If you have Swift experience please check the issues of the repo. Need assistance with the identical monitors issue, it’s there for two years already.
There are still some issues with some multiple port docks but so far that only turned out to be hardware related.
I'm the developer of Lunar so feel free to ask any questions about it.
Brilliant app that does the same for windows 10.
This might not work with all monitors.
Below are a bunch of my experiences with this which shows that behaviours are all over the place which kind of excludes an outright broken OS or piece of equipment. To me it looks much more like a compatibility issue.
I don't own a usb-c mac, but I've never had any problems whatsoever with my 2013 retina, always works perfectly even with 4k@60Hz screens.
I have a desktop PC which exhibits the same kind of weird behaviour you have. It has a thunderbolt 3 / usb-c / dp connector which is downright awful.
I've managed to connect an Apple thunderbolt display to it with official tb2 -> tb3 adapter, it works well most of the time. Put the computer to sleep though and the screen never comes back on. Sometimes it doesn't detect the USB ports on it either. Mostly works if I force the thunderbolt mode to DisplayPort only in the bios.
I've next connected a regular usb-c monitor to it (DP alternate mode + usb2 for peripherals). Works great in bios. Mostly works on Linux. On windows it turns off when getting to the login screen. I don't know how, but I've managed to get it to work exactly once. When I turned the computer back on the next morning, it was again off on the windows login screen. The monitor IS detected, it shows up in the Display Preferences if I connect it to both usb-c and display port. It just won't turn on.
On Linux, it kinda works. I would say there's a 50/50 chance it won't detect it at 60 Hz. Sometimes, if it works at 60Hz, if the display goes to sleep it won't come back on at 60Hz. I guess at least there is some output, so it's got that going over windows.
I found an option on the bios to enable "high speed display output". No idea what exactly that means, it didn't do anything.
This same screen works perfectly with a usb-c (no thunderbolt) laptop on linux. Never had any issue, always detected as 4k@60Hz.
The same monitor and same PC over DP: no problem.
Windows has two completely different APIs for adjusting screen brightness: one seems to only work on internal displays, the other seems to only work on external displays. I say “seems to” because they don’t document these facts, this is just what I observe by fiddling with the APIs. And only the first one is exposed anywhere in the UI: in Settings → System → Display (where you change the screen resolution and such) it lets you change the brightness of an internal display, but says something like “you can’t adjust the brightness of this device” for external monitors.
Laptop brightness keys (what Linux calls XF86BrightnessUp and XF86BrightnessDown) can’t be remapped by any means I know of. I don’t know of any way of being notified when the internal display brightness changes, either. I think you can poll the value, though it’s three years since I prodded this stuff and my memory is vague. Even so, it’d always be a delayed reaction. Kinda wish I were back on my last laptop where I used Arch Linux + i3 and handled XF86Brightness{Up,Down} myself.
(That brings me to my second major annoyance about built-in monitor brightness control software: stepping by a linear 10% the whole way is stupid; something like a logarithmic scale is much more sensible. The difference between 1% and 10% is at least as important in low lighting as the difference between 10% and 50%. I wrapped xbacklight to make it logarithmic on Arch, but I can’t do that on Windows, where the keys just jump by 10%. Similar deal with phone brightness, the difference two millimetres makes at the left end of the scale is more than the whole right hand half of the scale. Who on earth thought linear brightness was the right thing? Do they know nothing about human perception of brightness? Why is this obviously-badly-wrong practice universally adopted?)
What would be rather nice would be the ability to calibrate internal and external displays to match, so that the brightness of connected external displays could match my internal monitor immediately, following my chosen curve.
As it is, I use ScreenBright and script it so I can do both my external displays at once. (Now, I could reimplement the needed functionality from the relevant API in a short time, but ScreenBright does the job so I don’t bother.) I tend to type `b 20` in the mornings, sometimes `b 40` in the afternoons, and `b 0` in the evening. Seldom do I want to go past 40%. As I said, most people run their external monitors too bright, often much too bright.