I want to have an indicator that the Pi is running an wired a LED to GPIO 21 (with a resistor). When manually turning on the LED via /sys/class/gpio the LED turns on. Unfortunately, it does not give me a heartbeat when using:


in the /boot/config.txt.

Am I missing something?

  • What does sudo vcdbg log msg say about the params? – Dirk Dec 12 '18 at 21:55

I use dtparam=act_led_trigger=heartbeat which works on all my Pi.

(I have never tried pwr_led_trigger because the PWR LED is useful and never with an external LED).

I am not sure that this is even possible on the Pi3 the act_led_gpio states "N.B. For Pi3 see pi3-act-led overlay" but there is no corresponding overlay for pwr-led. (The Pi3B+ has totally different power circuitry.)

  • works with the act led. The pwr led seems to be hardwired and cannot be changed... – Nidhoegger Dec 13 '18 at 12:15

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