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Most Stable Raspberry Pi? Better NTP with Thermal Management

austinsnerdythings.com

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Re: Most Stable Raspberry Pi? Better NTP with Thermal Management

#71

Post by auspiv »

tw1984 wrote: post #45

some ideas - 1. using a second hand single frequency Ublox LEA-M8T GNSS receiver is not a good idea in 2025 when a dual frequency GNSS receiver chip can be purchased online for as little as $20-30. buy one of those ublox ZED-F9P receivers with the 2018/2019 firmware, they get you the exact same timing performance as ZED-F9T with QEerr support. PPS jitter is going to drop from 20ns to less than 2ns after qErr compensa…

1 - I like to consider myself an expert eBay-er (my ebay account can legally buy alcohol in the US, and I am myself only 36 years old) but I have not found any ZED-F9P for less than $90 ish. I am aware of the Quactel (sp) modules, and am considering a set for some RTK experiments. Is that what you're referring to?

2 - I've thought about replacing with ocxo but the pads are tiny. My soldering skills aren't nearly as good as my ebaying skills.

3 - it is outputting 16 Hz, chrony is doing dpoll -4 poll 4.

4 - I have done tempcomp (it is not active for the post referenced by this HN post). Fun stuff and probably my next writeup.

Re: Most Stable Raspberry Pi? Better NTP with Thermal Management

#72

Post by auspiv »

jauntywundrkind wrote: post #7

Amazing project, great write-up. Would love to see a temperature graph as well! I'm wondering how good the PID controller here is working. For future improvements, a cheap but effective win might be to put a temperature sensor on the oscillator (or two or three in various places). And use that to drive the PID loop. Even if just experimental & not long term, it would be nice to have data on how strong the correlation…

I for sure thought I included one, updating with that in a min!

Others have mentioned the temperature compensation. I've done it and it sounds like I should do that for the next writeup. A simple DS18B20 close to the Pi produces reasonable results.

Re: Most Stable Raspberry Pi? Better NTP with Thermal Management

#73

Post by auspiv »

mort96 wrote: post #21

What's the point in reading posts like this when the solution "they" came up with is basically, "tell Claude to make a script which does whatever"? I read blog posts to read thoughts from people, not computers

There is a difference between telling Claude to do something and actually doing it, and writing about it. The fact that this has 199 points as of writing this comments means people want to read about the results. You will probably be quite unhappy to learn that Claude write the majority of the blogpost as well -

"Hey claude read my previous posts and this script and generate a new blog post about this temp control stuff. Generate whatever plots you want. Here's how you can access my influxdb with the data. Here's how you can ssh into the Pi to get the exact running scripts. Ok here's my wordpress token - upload it and the pictures. Oh it looks like your .md to wordpress failed really bad, read a previous post to find out how to format stuff. Oh the tables are still not right, try again." Maybe people would find that interesting as well!

Re: Most Stable Raspberry Pi? Better NTP with Thermal Management

#79

Post by ThrowawayR2 »

heresie-dabord wrote: post #60
echelon_musk wrote: post #59

Earlier quoted context omitted.

> I don't think Intel has any "efficient" CPU that can go passively cooled at load though. Maybe Apple can do it for the low end SoCs. Does the N100 not fit this criteria?

The N100 requires active cooling.

Not necessarily; for example, the LattePanda Iota SBC with an Intel N150 has a passive heatsink option. Also, industrial fanless PCs have around for a long time even for much more powerful x86 processors.
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