[beaglebone] Switching off backlights...


When using a beaglebone with LCD7, there are many flashing lights...

After loging into the serial console I changed to runlevel 3 to get
rid of the running X11 GUI. The lesser is running on the bone the
lesser can interfer with the following

    opkg update
    opkg upgrade

Since the whole thing seems to take some time, I want to switch
off the backlight of the LCD7...and if possible other lights like
the ever blinking LEDs...

How can I accomplish this?

Thank you very much in advance for any help!

Best regards,


Hope this tidbit helps you out…

100% brightness…

root@omap:/sys/class/backlight/pwm-backlight# echo 100 > brightness

50% brightness
root@omap:/sys/class/backlight/pwm-backlight# echo 50 > brightness

Turn it off…
root@omap:/sys/class/backlight/pwm-backlight# echo 0 > brightness

(yes, I had to go as a super user as I am running Ubuntu)

And as far for those lights…

in the /sys/class/leds directory… (again may have to do this with superuser privileges for now… esp. if you use Ubuntu)…
… you will see :

beaglebone::usr0 beaglebone::usr2 lcd7::usr
beaglebone::usr1 beaglebone::usr3

and for example on the user light on the lcd7::usr

give this a try :

  • echo 0 > brightness to turn it off,

  • echo 100 > brightness to turn it on…

  • to make that same light work as a mmc1 activity light : echo mmc0 > trigger

Actually, try cat trigger to explore other options. What you have in [ brackets ] in that file, is what the option is.

The same idea applies to beaglebone::usr1 thru 3 block device directories too.

The first thing I did when I got my BBone up and running was trying to figure out how to stop that flashing light. Apparently, you can make the lights blink with a timer (out of my league for now!), as a heartbeat, as an indicator for your network. Again, like I mentioned, cat trigger (to display your options) can give you some info. That’s all I know for now as I’m also a beginner with not much experience.

Hope it helps. Cheers!

Danno C.