Possible solution for possible Raspberry Pi Zero 2 W disconnects
I've had my RPi drop off my WiFi during an overnight print job. After a bit of searching I stumbled upon this: https://forums.raspberrypi.com/viewtopic.php?t=325095
TLDR being, the Pi has, by default, its WiFi power saving function enabled. This can be confirmed by issuing
sudo iw dev wlan0 get power_save
and getting
power_save: on
in response. The solution to that seems to be to add
/sbin/iw dev wlan0 set power_save off
to /etc/rc.local before the "exit 0" line.
So far my RPi has only disconnected once during a nightly print and then did not disconnect during another once I've made the change so the "proof" is anecdotal at this point but I decided it's worth sharing here, regardless.
Cheers,
Zbig
RE: Possible solution for possible Raspberry Pi Zero 2 W disconnects
Okay, thank you for discovering that, we'll make sure to turn it off in the next image, if we manage to replicate it. That with the less frequent requests might make the wifi usable again. Awesome
RE: Possible solution for possible Raspberry Pi Zero 2 W disconnects
Unfortunately, this change alone has not solved my disconnection problems. It still might prove beneficial in achieving more stable connection, though.
As a test, I've been running my Raspberry Pi Zero 2 W off-board by connecting it to Einsy via cables for some time and I haven't had any disconnections when using it this way. This leads me to believe the potential root cause could be narrowed down to either overheating of the Pi being so close and intimate with Einsy board or electromagnetic interference issues. If the issue wasn't elusive enough, just to muddy the waters even further, there seems to be some variance to the Pi Zero 2 W hardware that could make just some of the specimens marginal with regards to their WiFi connectivity, see this Raspberry Pi Github thread.
What I'm testing right now is a custom bracket that goes on the original Einsy case but allows the Pi to be mounted some > 20 mm off the board using some extra-long pins. It gives the Pi more room to breathe and allows for mounting of mini stick-on radiators on Pi's SoC and WiFi can. So far so good but I still have to print some more to be able to call the fix working.
RE: Possible solution for possible Raspberry Pi Zero 2 W disconnects
Wow, thank you very much for the independent tests. We know the einsy is noisy, so this makes a lot of sense. I'll be looking forward to the results and maybe try replicating and testing some too.
RE: Possible solution for possible Raspberry Pi Zero 2 W disconnects
Sure, no problem, glad I can help. After several more hours of printing I can, with fair amount of confidence, conclude that this is working for me. I have put the Raspberry Butt Bracket and the instructions on Printables. I'm looking forward to any comments or feedback.
RE:
Idea, make a DIY RF shield for the back of the einsy. That should have a similar effect and should look better right? I think nothing fanc is required, insulate a piece of aluminum foil in some tape, cut out and insulate a square for the pins and stick it on there. Or i'll do it. Eventually 😀 I'm between vacations.
Edit: Maybe it needs grounding, idk, can't find, does it?
RE: Possible solution for possible Raspberry Pi Zero 2 W disconnects
Idea, make a DIY RF shield for the back of the einsy. That should have a similar effect and should look better right? I think nothing fanc is required, insulate a piece of aluminum foil in some tape, cut out and insulate a square for the pins and stick it on there. Or i'll do it. Eventually 😀 I'm between vacations.
Edit: Maybe it needs grounding, idk, can't find, does it?
I thought about it too but wanted something that deals with both temperature and EMI as a first try. I'm still not 100% sure it's just EMI as when I run a few prints with original frame but without the small Raspi cover and with a blower fan directed at Raspi, I didn't have any disconnects either, although I wasn't testing it like that for long.
Yes, for the shield to be effective, it'd have to be grounded. I think just tying it to the GND pin you're already using should do. Ideally it should have some cutout where the PCB antenna on the Pi is, so we do not block the WiFi transmission in this direction.
Anyway, have a nice vacation!