RPi-zero 2 W heat issues


Vic WA4THR
 

I just checked (left the rig so I could access it remotely with VNC) and it is 35% or less on the CPU running Fldigi, but not much to decode right now. With WSJT-X it sits at around 10% and jumps to 40% max when decoding the many signals on the band. With the new case it is staying nice and cool and working well and has been on about 24hrs right now.

=Vic=


N5XMT
 

what trends in CPU usage are you seeing with top while running fldigi vs other software?  is it constantly at 40% CPU?  


On Tue, Nov 16, 2021 at 10:25 AM Vic WA4THR via groups.io <vhklein=ptd.net@groups.io> wrote:
Some good ideas here. Note, I have more than enough speed to run Fldigi and WSJT-X with the zero 2...no issues with that and I think there is some excess capability, which is why I was thinking of "underclocking". I had run the original Pi-zero overclocked about 10%, but never had any heat issues.

The Swap file only gets to about 70%, as does memory usage in the worst case and usually less. CPU usage is below 40%. The only issue has been heat buildup and shutdown, and only when running Fldigi. I can delay it by leaving the top off the small case, but as room temps rise into the 70's even that is not enough. I just checked and the "slow CPU" option was automatically selected on the 4.1.01 version I am using. The diplay is optimized for the little 8" display on the Kindle Fire I am using to interface with the Pi. Bluetooth is off, but the WiFi is a critical part as the unit is running headless and linking to a simple tablet in the field, even out of WiFi range using it as a hotspot.

Is there a heatsink somewhere that is the same size as the whole Pi-zero that could substitute for the plastic top of the Vilros mini-case or something similar? That roughly 800% increase in surface might do the job.

=Vic=


Charles Albert
 

Indeed, the FLRIC case is the one, dissipates the heat, does the job.


Vic WA4THR
 

I switched to the aluminum FLIRC Pi-zero case and my problem is solved! With continuous FLdigi use the temperature of the processor is not getting over 115F (46C) and no more shutdowns. That is a very nice package. Also, not seeing any WiFi issues, but I am seldom more than 6ft from the Pi so if it is slightly attenuated I am not seeing it on the router or the tablet.

=Vic=


Vic WA4THR
 

Some good ideas here. Note, I have more than enough speed to run Fldigi and WSJT-X with the zero 2...no issues with that and I think there is some excess capability, which is why I was thinking of "underclocking". I had run the original Pi-zero overclocked about 10%, but never had any heat issues.

The Swap file only gets to about 70%, as does memory usage in the worst case and usually less. CPU usage is below 40%. The only issue has been heat buildup and shutdown, and only when running Fldigi. I can delay it by leaving the top off the small case, but as room temps rise into the 70's even that is not enough. I just checked and the "slow CPU" option was automatically selected on the 4.1.01 version I am using. The diplay is optimized for the little 8" display on the Kindle Fire I am using to interface with the Pi. Bluetooth is off, but the WiFi is a critical part as the unit is running headless and linking to a simple tablet in the field, even out of WiFi range using it as a hotspot.

Is there a heatsink somewhere that is the same size as the whole Pi-zero that could substitute for the plastic top of the Vilros mini-case or something similar? That roughly 800% increase in surface might do the job.

=Vic=


Mérlin
 

You could try reducing the background tasks or a different 'cleaner' image which has less of the unnecessary background tasks already removed(i dont know how much of background processing the standard image of the R-Pi Zero takes) Might also try reducing the display resolution as then the GPU wouldnt have to work that hard. Also turn off Wi-Fi/Bluetooth if possible. These are just some of the things that jump out to me while attempting to make the Pi go QRP!
-Mérlin


David Ranch
 


Hello Vic,

I have had a Raspberry Pi-zero W for a while for portable digital ops...nice and compact and runs forever with low battery drain, but it is a bit slow.

Makes sense since it's basically a Rpi v1 with a single old ARM v6L core but without HDMI, wired Ethernet, etc.


So, when the zero 2 W came out, I was eager to swap it in the same little case. It is fantastic, FT8 decodes right away and Fldigi loads and runs well

It's basically a depopulated Raspberry Pi 3 with less RAM.  I'm surprised programs like these run very well at all with only 512MB of RAM.  Are you sure your Rpi isn't swapping when running say Fldigi?  Look at the "used" column when running the command line program "free".  It will never be zero but if it's consuming all of your configured swap, performance will be dramatically impacted and your SD card will fail far sooner than it should.     Btw, if you're not running the new Raspberry Pi OS "Bullseye" release yet, be warned as this will probably get harder to run big memory footprint programs with that OS version due to additional bloat.


...except for one thing. Running only Fldigi and Conky to monitor the processor the heat steadily rises relatively quickly until somewhere past 134F it shuts the thing off. Adding a heatsink helps, but the rise is inevitable and happens within 20 minutes or so, depending on ambient temperature, even with the Pi out of the case.

It all comes down to cooling.  You're doing the right things here.. hopefully that's a good heat sink with a good thermal pad (many cheap heatsinks have *terrible* thermal pads btw).  You might consider trying other BIGGER heatsinks or even entire-case heatsink cases like the FLIRC line of all-metal cases ( https://flirc.tv/more/flirc-raspberry-pi-zero-case ).  If your case+heatsink has good ventilation for the heat build up, maybe you need a fan for those high CPU draw scenarios.


I could add a small fan, but now I am defeating the size and power use benefit.

Instead of a full time fan, you might consider running a temperature controlled *variable* speed fan:   https://www.trinityos.com/HAM/CentosDigitalModes/RPi/rpi4-setup.html#60d.appendix-cases-fanctl .  The solution is quiet and only runs the fan fast enough to get the meet the temperature you set.


Note that this problem seems to be only with Fldigi, not any of the other programs like WSJT-X or LinPSK that run cool and work well. So my question is whether there is something I could do like underclocking to control temps when running this program? Any other ideas?

Underclocking and undervolting might be a possibility but it also might slow the Pi down enough that those applications won't run very well anymore:

   https://www.reddit.com/r/raspberry_pi/comments/aki1is/reducing_power_of_the_raspberry_pi_3_b/


There are other settings in Fldigi that might help here:

   - Turn on the "Slow CPU" feature - http://www.w1hkj.com/FldigiHelp-3.22/miscellaneous_configuration_page.html
   - Slow or outright stop the waterfall


--David
KI6ZHD


Don Rolph
 

I got a 14 mm square aluminum heat sink and placed it on my Raspberry PI Zero 2 W.  I do  not seem to be having issues.  My case has plenty of ventilation.


On Tue, Nov 16, 2021 at 9:46 AM Vic WA4THR via groups.io <vhklein=ptd.net@groups.io> wrote:
I have had a Raspberry Pi-zero W for a while for portable digital ops...nice and compact and runs forever with low battery drain, but it is a bit slow. FT8 doesn't get decoded before the next cycle most of the time, making for repeats, and Fldigi just won't run. So, when the zero 2 W came out, I was eager to swap it in the same little case. It is fantastic, FT8 decodes right away and Fldigi loads and runs well...except for one thing. Running only Fldigi and Conky to monitor the processor the heat steadily rises relatively quickly until somewhere past 134F it shuts the thing off. Adding a heatsink helps, but the rise is inevitable and happens within 20 minutes or so, depending on ambient temperature, even with the Pi out of the case.

I could add a small fan, but now I am defeating the size and power use benefit. Note that this problem seems to be only with Fldigi, not any of the other programs like WSJT-X or LinPSK that run cool and work well. So my question is whether there is something I could do like underclocking to control temps when running this program? Any other ideas?

=Vic=



--

73,
AB1PH
Don Rolph


Vic WA4THR
 

I have had a Raspberry Pi-zero W for a while for portable digital ops...nice and compact and runs forever with low battery drain, but it is a bit slow. FT8 doesn't get decoded before the next cycle most of the time, making for repeats, and Fldigi just won't run. So, when the zero 2 W came out, I was eager to swap it in the same little case. It is fantastic, FT8 decodes right away and Fldigi loads and runs well...except for one thing. Running only Fldigi and Conky to monitor the processor the heat steadily rises relatively quickly until somewhere past 134F it shuts the thing off. Adding a heatsink helps, but the rise is inevitable and happens within 20 minutes or so, depending on ambient temperature, even with the Pi out of the case.

I could add a small fan, but now I am defeating the size and power use benefit. Note that this problem seems to be only with Fldigi, not any of the other programs like WSJT-X or LinPSK that run cool and work well. So my question is whether there is something I could do like underclocking to control temps when running this program? Any other ideas?

=Vic=