Safe Shutdown for RPI while mounted in rack

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fear3ck
Posts: 4
Joined: Sun Aug 12, 2018 4:54 pm
Real Name: Julian

Hello,

I'm using QLC+ on a RPI 4 to trigger our floorpack with midi commands from logic which works absolutely perfect.
Since the RPI is mounted in our Stagerack I'm always worried about a unsafe shutdown if somebody unplugs the rack suddenly after the set.

In my perfect world we simply can unplug our rack and can forget about the Pi.
I found some UPS hardware solutions which all seem to be more like a safety feature for NAS rigs where the Pi needs to be up and running all the time.
Also using a powerbank between power supply and RPI won't solve the problem - I want to shutdown the Pi after our set, but safely :D

Then there is a potential software solution to make the filesystem read-only. Would this have an impact to the QLC instance anyhow?

Did anybody found a Solution for this?

Thanks and Best
Julian
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mcallegari
Posts: 4914
Joined: Sun Apr 12, 2015 9:09 am
Location: Italy
Real Name: Massimo Callegari
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I have found this article that might help.
https://www.dzombak.com/blog/2024/03/ru ... ilesystem/

However, I'm not sure if everything can be applied to the current image.
QLC+ writes a few things in the configuration folders but basically just once.
So if you load your workspace and configure IO, I think (but needs to be verified) that no more writings are needed on the SD card, so the filsystem could be read-only.

Please let us know if you progress on this topic.
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msec74
Posts: 10
Joined: Fri Jan 24, 2025 8:21 am
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Hi Julian,

I did not yet test this myself, but I can imagine it as an path forward for you.
Use 2 power supplies in the Rack, one is connected with a small powerbank and powers the Raspberry.
The second one is only operating a relay that is grounding one of the GPIO Pins. The Module/Function gpio_shutdown could be configured to safely shutdown the PI, when the rack goes black and the powerbank is still providing energy.

If you would like to go fancy....use an (very well protected) Button in QLC/a midi command to switch an relay to trigger the power off after the show...

https://raspberrypi.stackexchange.com/q ... wn-buttons

Hope that does give an idea...how to potentially this.

Michael
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