How does this device showup in Windows User Inteface?

[NicksonYap]

Hi @3cky !

Very interesting project that I came across, wanting to have my desktop PC monitor adjust brightness based on ambient light

I was surprised no one is selling a USB accessory for this!

It was found that Windows has support for Ambient Light Sensor (ALS) but seems to be aimed towards OEMs or laptop manufacturers

https://learn.microsoft.com/en-us/windows-hardware/design/component-guidelines/ambient-light-sensors#integrating-light-sensors-with-device-hardware

And when HID was mentioned, I came across your GitHub project

So I wondered, does the device work as an ALS with Windows like if it were on the laptop?

If so, how does the UI in Windows look like after connecting this USB HID ALS
and how do we go about calibration of how much increase in ambient light would increase the brightness

Best,
Nickson

[3cky]

Hello Nickson,

My primary OS is Linux and I don't have any Windows box at hands right now, but as far I know it should be visible as a USB HID device in Windows device manager.

BTW, there is a fork with some Windows compatibility improvements, so you probably should take a look at it.

[yurixst]

Hi, there are screenshots in spark-als fork:
MatejKocourek#2

[MatejKocourek]

Hi, I am glad my fork is being useful. As for the question in the thread:
To automatically control a brightness of a monitor, Windows needs to have two things available: a source of ambient light data (sensor), and a way to control the brightness (monitor interface). The first of these is solved by this project (or my fork of it). With the sensor connected, Windows now has the capability of determining the light level. But to support brightness adjustments, the OS needs to be connected to a monitor which brightness levels can be controlled directly from the OS.
In other words, the Windows auto-brightness functionality will only work if you have a brightness slider available in Windows settings. To my knowledge, as of now only laptops support this functionality. Monitors connected externally (DP, HDMI, DVI, VGA) are not supported. This is frustrating, as there seems to be no real reason why - virtually all monitors made in the last 20 years support software controlled brightness adjustments though the DDC/CI interface. There are some third-party tools available to control it (check out Twinkle Tray or Monitorian), but the functionality has not yet been integrated into Windows.
Hopefully, someone at Microsoft might one day decide to implement it, as there is all the hardware support needed. But as of now, the Windows auto-brightness function will not work on other than laptop displays.
The support for HID light sensors might get integrated into some third party tools that might try to replicate the Windows auto-brightness behavior, but I have not seen any available. Which is why I also started working on such a program myself. At the moment is does not have a GUI, and its capabilities are quire limited, which is why I haven't yet published it online, but I can if you want to. I use it myself in combination with the HID sensor to auto-control my brightness and it does the job. If you or anyone would be interested in working on it, that would also be great.

[NicksonYap]

Thanks @yurixst for sharing, the screenshot here of Windows Devices of the custom HID ALS makes a lot of sense
MatejKocourek#2 (comment)
Nice that it can show up on SensorExplorer as well, didn't know there is such an official app

Hi @MatejKocourek thanks a lot for your contributions
I was quite occupied and actually still interested in the project
A little surprised that such sensors are not commercially available and that Windows doesn't have built in support to control brightness via DDC/CI

I'm actually using Twinkle Tray at the moment

Regarding the code you're working on, I wonder, does it integrate with Twinkle Tray?