backmailingbox
Posts: 76
Joined: Tue Jan 19, 2016 2:30 pm

backlight, brightness control on official disp or another?

Fri Jan 29, 2016 7:53 am

Hi,
I have one piece of official 7'' rasp pi display
It is ok but one not nice thing.
I am not able to change brightness or backlight from python.
There is possibility only to switch backlight on/off.
It is not enough and this missing feature is really moving this display into ...
Not usable for any night device like weather station, alarmclock and so..

So I have 2 questions:

1. Will there be in short future any firmware update which enable brightness/backlight control
via sotware (python) on official rasp pi display?

2. Is there any other 7'' capacitive touch display on the market which enable software (python)
brightnes and backlight control?

jwatte
Posts: 203
Joined: Sat Aug 13, 2011 7:28 pm

Re: backlight, brightness control on official disp or anothe

Sun Feb 21, 2016 7:04 am

This code should work fine:

Code: Select all

f = open("/sys/class/backlight/rpi_backlight/brightness", "wb")
f.write("80\n")
f.close()
If it doesn't work, then one of two things are wrong:

1) You're using a v1.0 display instead of the v1.1 display -- I don't know if backlight adjust actually works on 1.0.

2) You're seeing a permission error and need to run as root, and/or you need to set the permissions of the /sys/class/backlight/rpi_backlight files.

I can confirm that I have a version 1.1 display, and I can change the backlight brightness with this code.

JimmyN
Posts: 1109
Joined: Wed Mar 18, 2015 7:05 pm
Location: Virginia, USA

Re: backlight, brightness control on official disp or anothe

Sun Feb 21, 2016 11:00 am

backmailingbox wrote:
1. Will there be in short future any firmware update which enable brightness/backlight control
via sotware (python) on official rasp pi display?
There is no firmware update, just a hardware update. The very recently released v1.1 screen has brightness control, but if you've had the screen for more than a couple of weeks you have v1.0 and there is no way to change brightness.

In answer to your second question, you can buy another 7" display (v1.1) and you'll have the compatibility and brightness control.

backmailingbox
Posts: 76
Joined: Tue Jan 19, 2016 2:30 pm

Re: backlight, brightness control on official disp or anothe

Sun Feb 21, 2016 11:40 am

Hi jwatte,
where and when did you buy version 1.1 display?

W. H. Heydt
Posts: 13957
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: backlight, brightness control on official disp or anothe

Sun Feb 21, 2016 5:38 pm

JimmyN wrote:
backmailingbox wrote:
1. Will there be in short future any firmware update which enable brightness/backlight control
via sotware (python) on official rasp pi display?
There is no firmware update, just a hardware update. The very recently released v1.1 screen has brightness control, but if you've had the screen for more than a couple of weeks you have v1.0 and there is no way to change brightness.

In answer to your second question, you can buy another 7" display (v1.1) and you'll have the compatibility and brightness control.
Thanks a bunch for that data. It answers some questions I've been mulling over.

Return to “Official Foundation Display”