LED which turns off when raspi is in standby

Hello everybody,
i am new here and want to say THANK YOU ALL for Volumio, the plug ins and all the work, that had to be done to reach this excellent stuff that you offer here. But i also have a question:
I would like to build a case for my raspberry, the DAC and the power supply, with buttons at the front (using the GPIO plugin) and a LED, which is on, when the system is running and off, when the raspberry is in standby after being shut down. I want to use a real power on/off switch in the cable to the power supply, to turn off the power completely, of course after the system did the regular shutdown. So: to know, when the shutdown has finished, i would like to have a LED that turns off, so that i am able to switch the power off completely without destroying anything. When i put a LED at one of the regular 3,3 V pins, it is still on, when the raspi is in standby-mode.
Any ideas how to do that? I am not good in linux/programming, so please keep it simple :wink:
Thanks in advance,
Ben

Hi Ben,

I have the same problem.

As an interim solution I used the signal from the “ACT” LED of the PI3 (see schematic - right middle section) :
https://www.raspberrypi.org/documentation/hardware/raspberrypi/schematics/RPI-3B-V1_2-SCHEMATIC-REDUCED.pdf

Another LED (with a resistor - see schematic) from 3,3V to the drain of Q6 does it. The LED stops flashing when the PI is down.
It was not the easiest mission to solder at the LED cathode. That’s something for specialists …

Cheers
Pirx

To switch-off power (or a led indicator) automatically after shutdown, you may want to look at gpio-poweroff overlay.
This allows to set a GPIO output pin from ON to OFF when shutdown has completed: this pin can then drive a switch to turn off power supply :wink:
Though I’ve not used it, it seems pretty simple to set through an overlay config in /boot/config.txt as usual.
Happy experimenting!

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Hi Pirx, hi macmpi,

thank you for your reply, i will take a look at your solutions as soon as possible and will reply, to let you know, what i did :slight_smile:

Cheers
Ben

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Hi again,

it took a while, but eventually i finished my RPI-project, using the overlay gpio-poweroff, as described at the link macmpi posted. It is not 100% what i was thinking of, but it works. Instead of a green LED signaling, that the RPI is on, there is a red LED signaling, that it is off, so that i can switch off the main power supply.K640_SDC12497.JPG

Great, happy it helped.

I now have a full automatic power off after shutdown. Power supply included!
For more see this thread: power-down-rpi3-iqaudio-dac-t6191-10.html

You can put the LED on one of the USB ports. I guess they will loose power after a shutdown.

just my 2 cents…

.Nico

Sorry for writing in this old thread…

But will this work? Did anybody test this?
Thanks.

Fabian

Hi Fabian,

I just tried it using a standard LED and it works.

The LED looses power a few seconds before the PI is down.

Cheers
Pirx

Thanks for testing it.
Best.
F