Fauveboy
Posts: 82
Joined: Sun Jan 26, 2014 8:09 pm

Raspberry Pi 7inch Touchscreen Brighness

Fri Sep 07, 2018 6:09 pm

How can I change the brightness of the official raspberry pi 7 inch touchscreen?

DirkS
Posts: 9460
Joined: Tue Jun 19, 2012 9:46 pm
Location: Essex, UK

Re: Raspberry Pi 7inch Touchscreen Brighness

Fri Sep 07, 2018 6:14 pm

Write a value between 0 to 255 (inclusive) to /sys/class/backlight/rpi_backlight/brightness

e.g.

Code: Select all

sudo sh -c 'echo "100" > /sys/class/backlight/rpi_backlight/brightness'

W. H. Heydt
Posts: 9211
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: Raspberry Pi 7inch Touchscreen Brighness

Sun Sep 16, 2018 2:33 am

DirkS wrote:
Fri Sep 07, 2018 6:14 pm
Write a value between 0 to 255 (inclusive) to /sys/class/backlight/rpi_backlight/brightness

e.g.

Code: Select all

sudo sh -c 'echo "100" > /sys/class/backlight/rpi_backlight/brightness'
You don't need quotes around the brightness value. The root crontab entry to dim the 7" display on my "alarm clock" is...

Code: Select all

# Evening Dim Display
00 22 * * * echo 17 > /sys/class/backlight/rpi_backlight/brightness

DirkS
Posts: 9460
Joined: Tue Jun 19, 2012 9:46 pm
Location: Essex, UK

Re: Raspberry Pi 7inch Touchscreen Brighness

Sun Sep 16, 2018 9:15 am

W. H. Heydt wrote:
Sun Sep 16, 2018 2:33 am
You don't need quotes around the brightness value. The root crontab entry to dim the 7" display on my "alarm clock" is...

Code: Select all

# Evening Dim Display
00 22 * * * echo 17 > /sys/class/backlight/rpi_backlight/brightness
I can't see any mention of crontab or startup in OP's post...

W. H. Heydt
Posts: 9211
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: Raspberry Pi 7inch Touchscreen Brighness

Mon Sep 17, 2018 2:14 am

DirkS wrote:
Sun Sep 16, 2018 9:15 am
W. H. Heydt wrote:
Sun Sep 16, 2018 2:33 am
You don't need quotes around the brightness value. The root crontab entry to dim the 7" display on my "alarm clock" is...

Code: Select all

# Evening Dim Display
00 22 * * * echo 17 > /sys/class/backlight/rpi_backlight/brightness
I can't see any mention of crontab or startup in OP's post...
I could have stripped off the cron timing and stuck "sudo" in front of the command. it's simply an illustration that you don't need to put to value for the backlight in quotes.

DirkS
Posts: 9460
Joined: Tue Jun 19, 2012 9:46 pm
Location: Essex, UK

Re: Raspberry Pi 7inch Touchscreen Brighness

Mon Sep 17, 2018 8:47 am

W. H. Heydt wrote:
Mon Sep 17, 2018 2:14 am
I could have stripped off the cron timing and stuck "sudo" in front of the command. it's simply an illustration that you don't need to put to value for the backlight in quotes.
By adding the irrelevant cron thing you are more likely to confuse users.
IMNSHO it would have better if you had not responded at all instead of using the cron example just to show that there is an alternative way of formatting the command.

W. H. Heydt
Posts: 9211
Joined: Fri Mar 09, 2012 7:36 pm
Location: Vallejo, CA (US)

Re: Raspberry Pi 7inch Touchscreen Brighness

Tue Sep 18, 2018 3:15 am

DirkS wrote:
Mon Sep 17, 2018 8:47 am
W. H. Heydt wrote:
Mon Sep 17, 2018 2:14 am
I could have stripped off the cron timing and stuck "sudo" in front of the command. it's simply an illustration that you don't need to put to value for the backlight in quotes.
By adding the irrelevant cron thing you are more likely to confuse users.
IMNSHO it would have better if you had not responded at all instead of using the cron example just to show that there is an alternative way of formatting the command.
Perhaps we should wait to see if the OP expresses any confusion before jumping to that conclusion.

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