Switching a Pi off

ianhaynes

Having used Rune with a Pi and IQAudio DAC as a lash-up for several weeks I want to put it in an enclosure and make it usable for the rest of the family. One issue seems to be that of switching it off carefully so the SD card doesn't get corrupted.

How have people done this? Any suggestions?

bevlar

In RuneUI
Menu > Turn off > Power off

This halts the system so you can safety power down the pi.

Corruption should only occur if you pull the power while the system is running.

ianhaynes

Yes but that's the point, other users aren't necessarily going to remember that. I'm looking for a foolproof way of shutting down. I'm aware of the Pi-Supply switch which aims to solve this but haven't been able to get it working with the Pi + IQAudio DAC.

bevlar

Would other user turn off their PCs or laptops without shutting them down properly first?

The simplest solution to this problem is educating the users.

Other than that you would need something like MoPi. Its a ups board, you could script it the shutdown when it switches to battery. You would need to check the pin out though to make sure it won't interfere with your DAC.

mspohr

I just leave it on all of the time. It takes so little power (just a few watts) that it's easiest to leave it on. Also, when I want to use it, I don't have to wait for it to boot. I have it stuck in the bottom of the stereo (ne AV) closet and just forget about it. I access it through one of several tablets.

neanderthaler

I installed switch, resistors, led, python and the shutdown script from here:
http://www.forum-raspberrypi.de/Thread-tutorial-hoch-und-runterfahren-mittels-taster-incl-status-led
Needs to be adopted to archlinux: arch uses systemd instead of the debian sysvinit.
Works great, with no noticeable load on my slightly aged Pi B+.
I use an USB-DAC, but it should work with I2S-DACs as well. The relevant IOs are not used by iqaudio AFAIK.
If you are not afraid of playing around with linux, just give it a try!
Well worth it, IMHO.

ianhaynes

Many thanks, looks to be a good solution.

bevlar

You can use cron to start your script at boot/reboot

pacman -Syy cronie

EDITOR=nano crontab -e
@reboot /usr/bin/python /path/to/script.py &

neanderthaler

Jepp, cron will do the job, too.
I for myself didn't like the idea to have an additional deamon running, even without noticeable load. Systemd is running anyway.
BTW, maybe it's necessary to remove "sudo" in the next to last line of "shutdown.py".

bevlar

Yeah systemd is definatley the way to go but I'm fairly new to arch so I'm still finding my feet. I did install a shutdown/reboot service to reset some relays but I just copied the code and adjusted it to run my script instead I don't fully understand how it works.

You are correct about sudo, rune only has the root account enabled. Sudoing commands will throw an error.

noxx2

neanderthaler wroteI installed switch, resistors, led, python and the shutdown script from here:
http://www.forum-raspberrypi.de/Thread-tutorial-hoch-und-runterfahren-mittels-taster-incl-status-led
Needs to be adopted to archlinux: arch uses systemd instead of the debian sysvinit.
Works great, with no noticeable load on my slightly aged Pi B+.
I use an USB-DAC, but it should work with I2S-DACs as well. The relevant IOs are not used by iqaudio AFAIK.
If you are not afraid of playing around with linux, just give it a try!
Well worth it, IMHO.

hello neandertahler

i use on my PI the same solutiuon, under Raspian works this good. But i dont know what i must installed
on a Arch-System?
perhaps you can help (or anyone other).

regard

neanderthaler

Hi noxx2,

- install python and RPi.GPIO as described here: #636
- copy shutdown_switch.py to /usr/bin, remember to remove "sudo" and

chmod 755 shutdown_script.py

- create a new service-file /usr/lib/systemd/system/shutdown_pi.service with this content:

[Unit]
Description=shuts down the Pi if button pressed
Requires=
After=

[Service]

Type=simple
ExecStart=/usr/bin/python /usr/bin/shutdown_switch.py
TimeoutSec=0

[Install]
WantedBy=multi-user.target

- do a

systemctl enable shutdown_pi.service

Reboot and you're done.
Good luck

yjo

Hi,
I installed a button switch and an LED.
The hardware and software are both very simple.
The short push of the button toggles play/pause, and the long push (indicated by the LED) starts shutdown.
The control script is written in shell script, so installation of python or so is not required.

http://yjo-blog.blogspot.com/2015/02/runeaudio-03.html

yjo

neanderthaler

Hi yio,

your solution with bash scripting looks indeed promising.
Did you check if it causes any measurable load on cpu?

BTW, to start (again), you have to unplug and plug in the power source?
When I find some spare time, I'll try to merge start function into your bash script. It's just one more GPIO. Pentecost, or summer holiday, or christmas...

Isn't it great to find at least some solutions to this !"§$%&! problem?
I like this forum.

yjo

> your solution with bash scripting looks indeed promising.

Thanks. Simple is best

> Did you check if it causes any measurable load on cpu?

"ps -aux" reports as below:

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root       138  2.0  0.1   3364   812 ?        S    20:05   0:40 /bin/sh /usr/bin/shutdownbt_led.sh

This means this daemon script affects little the performance of the whole system, I think.

> BTW, to start (again), you have to unplug and plug in the power source?

Right, but I installed another paddle switch for turning the power on/off.
For restarting the Pi, I just turn off the switch and then turn it on again.

: raspi.jpg (118.72 KiB) Viewed 3817 times

The script, switch, and LED work well on not only Rune but also Volumio and moode audio

I didn't test on Archphile -- maybe my todo

PS. An IR remote controller also works well on Rune, Volumio, and moode. I can also shutdown (and reboot) the Pi from the remote controller.
yjo