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Howto control CubieTruck onboard LEDs

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Today I wanted to know, what this little blinking lights on my [amazon &title=CubieTruck&text=CubieTruck] mean.

There are four, which you find out if you use:

root@cubietruck:/# ls /sys/class/leds/

blue:ph21:led1 green:ph07:led4 orange:ph20:led2 white:ph11:led3

(or just look at it while it is running, usually it blinks a lot)

IMG_20140520_123004

So if you want to know what each blink means you can ask the [amazon &title=CubieTruck&text=CubieTruck] like that:

root@cubietruck:cd /sys/class/leds/
root@cubietruck:/sys/class/leds# ls
blue:ph21:led1  green:ph07:led4  orange:ph20:led2  white:ph11:led3
root@cubietruck:/sys/class/leds# cat green:ph07:led4/trigger
none rfkill0 battery-charging-or-full battery-charging battery-full battery-charging-blink-full-solid ac-online usb-online [mmc0] mmc1 timer heartbeat cpu0 cpu1 default-on rfkill1 rfkill2 
root@cubietruck:/sys/class/leds# cat blue:ph21:led1/trigger
none rfkill0 battery-charging-or-full battery-charging battery-full battery-charging-blink-full-solid ac-online usb-online mmc0 mmc1 timer [heartbeat] cpu0 cpu1 default-on rfkill1 rfkill2 
root@cubietruck:/sys/class/leds# cat orange:ph20:led2/trigger
none rfkill0 battery-charging-or-full battery-charging battery-full battery-charging-blink-full-solid ac-online usb-online mmc0 mmc1 timer heartbeat [cpu0] cpu1 default-on rfkill1 rfkill2 
root@cubietruck:/sys/class/leds# cat white:ph11:led3/trigger
none rfkill0 battery-charging-or-full battery-charging battery-full battery-charging-blink-full-solid ac-online usb-online mmc0 mmc1 timer heartbeat cpu0 [cpu1] default-on rfkill1 rfkill2

So by default the

  • green LED is indicating if there is any read write with the SD Card
  • blue LED is heartbeating
  • orange LED is CPU0 load
  • white LED is CPU1 load

In case you want to turn off the LEDS, use this code:

# turn off LEDs
echo 0 > /sys/class/leds/blue:ph21:led1/brightness
echo 0 > /sys/class/leds/green:ph07:led4/brightness
echo 0 > /sys/class/leds/white:ph11:led3/brightness
echo 0 > /sys/class/leds/orange:ph20:led2/brightness

See here for more information.