Turning off the blue status LED

Owned by Sylvain Bernard
Last updated: Feb 10, 2023
1 min read

The MPCam uses 3 LEDs:

  • Power LED (red) => is turned on when power is applied.

  • User LED (red) => is controlled by software

  • Status LED (blue) => is controlled by the kernel

When the MPCam is fully booted, the Status LED may show Linux “activity”, which can be distracting…

Note that the Status LED is also used by the TF-A and U-Boot bootloaders.

The following method only works for turning it off once Linux is booted / running.

To disable from the console, run the following command

$ echo none > /sys/class/leds/heartbeat/trigger

Note: to turn it on/off:

$ echo 1 > /sys/class/leds/heartbeat/brightness $ echo 0 > /sys/class/leds/heartbeat/brightness

To disable it in your script, use the PyMPCam module:

from pympcam.userLed import UserLed led = UserLed() led.disableHeartbeat()

Note that disabling the Status LED is not persistent and it’ll resume on next boot.