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Turn off or reduce backlight (MPI3501)

Open Marcaru opened this issue 4 years ago • 14 comments

Hello

Is there any way to turn off or reduce the brightness of the lcd screen by software?

I have the MPI3501 model.

Bye

Marcaru avatar Apr 25 '20 16:04 Marcaru

Agree, that would be a nice feature.

MrRikkie avatar Apr 27 '20 16:04 MrRikkie

Also would like this feature

DrFredPhD avatar May 10 '20 12:05 DrFredPhD

Sorry, it needs hardware support to realize this function by software, but there is no backlight brightness control circuit in MPI3501 at present.

goodtft avatar May 30 '20 07:05 goodtft

Ok to bad, thanx for your answer.

MrRikkie avatar May 30 '20 08:05 MrRikkie

i had the same question. thx for the answer.

if I add some control to the power of the display and switch it off (while keeping my rpi zero running), will it resume nicely when I bring power back to the screen ?

nouknouk avatar Jun 01 '20 22:06 nouknouk

I tried out that, if i disconnect all the pins then reconnect then it does not work again, just shows the white display. but i think disconnecting the power pin will be enough to this trick, but i am not sure if driver will work or not.

rahmanshaber avatar Jul 03 '20 08:07 rahmanshaber

@goodtft okay i tested it and i tried disconnecting and reconnecting the power line and it works. https://youtu.be/0jL5CY34qXk

rahmanshaber avatar Jul 03 '20 09:07 rahmanshaber

Great, i will add a switch in the powerline.

MrRikkie avatar Jul 03 '20 13:07 MrRikkie

Great, i will add a switch in the powerline.

you have 3.5 inch or others? my one in 4 inch chines.

rahmanshaber avatar Jul 03 '20 13:07 rahmanshaber

If you're powering the display from the Pi, you can switch off USB power on the Pi using https://github.com/mvp/uhubctl

andreas-globi avatar Sep 25 '20 16:09 andreas-globi

Thanks @andreas-globi , does that turn of the whole PI or just the screen though?

shanness avatar Sep 27 '20 20:09 shanness

It will just turn off the screen (uhubctl let's you control power to the Pi's USB ports)

andreas-globi avatar Sep 27 '20 20:09 andreas-globi

Hey @andreas-globi , thanks for the reply. When I run this command, the screen dims a little for a split second but that's all. I've tried repeat and other options, but can't figure out how to get it to stay off. Any help would be much appreciated. Also, is it possible to turn it back on when touched? sudo uhubctl -l 1 -a 0

shanness avatar Sep 30 '20 14:09 shanness

I don't know. It's not my library. I was just sharing to be helpful as it helped me in my case.

andreas-globi avatar Oct 18 '20 20:10 andreas-globi