CM3 Screen Brightness

[lubosz]

I really like my CM3 build, but one of the most annoying things is the high screen brightness,
it's not only hurting my eyes but it's draining the battery unnessecarily.

According to this thread there could be some options though:
https://forum.freeplaytech.com/showthread.php?tid=4495

I'm sorry to say that the brightness on the Freeplay Zero is not configurable.

For future versions of the Freeplay CM3 (or if people want to mod their own board), we are looking into some options, because the Compute Module 3 has a lot more GPIO lines available.

If it's not possible in hardware, I guess a transparent black overlay could also be hacked to work in software, like the ES screensaver you get when you press Select.

Do you know of any progress here?

[Flavor]

We're working on a dimmer add-on. In fact, just today we did some new testing on it. I hope to be able to post something about that soon. I think it will be a pretty simple add-on to install, but it may require soldering 2 wires (to spots that should be fairly simple to access). It would also require a bit of software to be added to the Freeplay CM3 (or Zero) to set the backlight brightness.

[lubosz]

+1 on the waiting list for this part

[Flavor]

I was working on the software again today. Once I have some software that can integrate into the RetroPie menu easily (to set the backlight brightness), I think we'll announce a small test batch of the dimmer add-on.

[RxBrad]

Nice. Now that I finally have a working Pi0 for my FPZ, I may have to jump on board for this, too.

I'm curious, since I'm no electrical engineer; does a resistor to reduce screen brightness actually decrease power draw? (i.e. will the battery last longer). Or is this going to be a PWM change on the Pi itself? Or should we just wait and see...

[Flavor]

Yeah, the resistor method would help. The main problem is that there isn't a good way to add such a thing on the current version. Our current idea is to make a ribbon cable extension that would plug between the LCD and the Freeplay circuit board. On that, you could do a resistance, but we will go the PWM route and allow the user to set it via software.