ouzle

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Going back to the original thermal design but adding heat sink compound between the heat spreader and the motherboard is messy and didnt help with CPU throttling. It doesn't get any more heat to the keyboard than the original heat spreader contact with the motherboard. I think the keymat must be a good insulator.

When I shutdown after a full cpu load test (CPU was at 90C) the back of the cpu board was at ~60C when I whipped the battery out.
20210328_230024~2.jpg
 

levi

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Yes, the keymat is made of rubber, which is essentially long chains of coiled hydrocarbons, so heat is as likely to return to the same surface it left as it is to the other side, and the way they're all packed together helps stop vibrations travelling, which essentially is how you stop conduction of heat.
 
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EvilDragon

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The priority for me is to get an air gap between the CPU board and the battery into the case mold. This can then be covered over with the existing sticker and optionally packed with a very open insulating foam. I think this helps with charging the pyra when in use as the battery runs 4 or 5C cooler for equivalent use cases.
We originally had a gap of 0.4mm there which did cost us 2000 EUR extra to build. Unfortunately, when we moved the moulds to the new company, they didn't include that part and therefore, the plastic between the battery compartment and the CPU board is too thick. I found that out when assembling the current units...

The transparent prototype cases have the thinner walls.

We're working on a solution here, but I'm also following this thread. Anything we can do to improve the thermal design is great :)
 

hns

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I don't understand the meaning of the bq24297-i2c-1-6b temperature reading. Is this just a flag to trick the governor into throttling when the battery gets too warm? It only has two values of 22C or 60C.
It can have a third value -10C... The reason is that the bq24297 can only report good, hot, cold and no values in between. It is a limitation of the chip design which we have tried to convert to reasonable values...
Post automatically merged:

The temperature sensors are commonly within the battery package itself, that's why the battery has a 3rd contact.
And this within-the-battery sensor is reported by the bq24297 while the bq27421 reports its chip temperature (outside of the battery).
In an ideal world the bq24297 would be able to report the within-the-battery temperature in 1C steps and not ~35C steps.
 
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Letalis Sonus

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So why does the bottom of the CPU board get so hot still?
AFAIK the silicon dies are mounted upside down. Add in the less ideal heat transfer of the plastic casing and the chip will simply push much more heat down its contacts to the board than to any heatsink on top of it.
 

matzesu

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I wonder: Is this just a Modding Projekt, or do whe normal users also need a better heat spreading solution?
Will the Omap 5 just shut down when its get to warm?
Could i still play Tetris in August outside when he have around 35 degrees Celsius?
 

matzesu

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Well, its the same as when someone from the North Pole writes something about he put some snow chains on his car, and for the rest of the Boards, its Summer .. ^^, The Threadstarter experiments whit Thermal Solutions on his Pyra, but for us it sounds like the Stock Solution dosnt work..

At least i hope so, but i dont have that much experience as my Pandora only got warm because of the heat from outside..
 

ingoreis

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This thread got me kinda worried...
Do not worry..we have a working Thermal Solution,this Thread is only experimenting how to make the cooling better for CPU BOOSTING ;)
Well, its the same as when someone from the North Pole writes something about he put some snow chains on his car, and for the rest of the Boards, its Summer .. ^^, The Threadstarter experiments whit Thermal Solutions on his Pyra, but for us it sounds like the Stock Solution dosnt work..

At least i hope so, but i dont have that much experience as my Pandora only got warm because of the heat from outside..
I do not realy worry about Heat on the Pyra..i had the Luck to use a Prototype @ the Gamescom before 2 Years and all was good usable there too.
That was in a Time where no Heat Solution was there and i used the Pyra about 2 Hours.
It was the Pyra from @Askarus and i did helped him a little bit with installing the "open Terminal here" Option in Debian and tried some other Things.
 
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ouzle

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I wonder: Is this just a Modding Projekt, or do whe normal users also need a better heat spreading solution?
Will the Omap 5 just shut down when its get to warm?
Could i still play Tetris in August outside when he have around 35 degrees Celsius?
Yes, keep in mind that I've bought into the Pyra because I love taking things apart for fun to understand how it works. The thermal design got my interest first as I often do thermal calculations at work.

Id rather try to help out software / kernel but that's a bigger learning curve for me.
 

matzesu

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Well, your Topic is quite interesting, maybe this is one of the reasons whe like these Handhelds: You can Mod them, but you dont have to, but when you mod, the other members are happy if you share your results ^^,

There where quite interesting mods on the GPH Handhelds and on the Pandora, some even put a second pair of Shoulderbuttons in the Pandora, or an USB Hub or something..

Others, like me are just happy when thyre Stock Pyra works, my only Mod is a Lanyard from a Nintendo 3DS Circle Pad Pro..
 

ouzle

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My Idea is..cooling the USB Port more=cooling the CPU more.
Something like this? I've attached a bigger aluminium heat sink to the original heat spreader that goes to the CPU chips and usb ports. Its in good contact with both usb ports.

The bottom of the CPU board has the cold finger going to the side of the case with a low profile NVMe heatsink attached. I made a slot in the thermal pad to fit the side copper tab from my cold finger. EDIT: I used a bit of cyanoacrylate to hold the nvme heatsink along the edge of the copper.

The silver heatsink is 36mm long, 11.5mm wide and 10mm high. It protrudes by 2mm but I could file it down. I applied thermal paste to the original pyra heat spreader tab bottom and its held in place by friction. I took a 10mm drill bit to the case to open up the vents and filed the case to make it a tight fit. I guess the thermal resistance is about 30C/W with minimal air flow.

Both heatsinks get to about the same temperature.
20210329_140817.jpg

20210329_140756.jpg
 
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Silent-Hunter

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It can have a third value -10C... The reason is that the bq24297 can only report good, hot, cold and no values in between. It is a limitation of the chip design which we have tried to convert to reasonable values...
Post automatically merged:


And this within-the-battery sensor is reported by the bq24297 while the bq27421 reports its chip temperature (outside of the battery).
In an ideal world the bq24297 would be able to report the within-the-battery temperature in 1C steps and not ~35C steps.
I've been having i3status read the wrong temperature sensor then.
 

Silent-Hunter

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I do not realy worry about Heat on the Pyra..i had the Luck to use a Prototype @ the Gamescom before 2 Years and all was good usable there too.
That was in a Time where no Heat Solution was there and i used the Pyra about 2 Hours.
It was the Pyra from @Askarus and i did helped him a little bit with installing the "open Terminal here" Option in Debian and tried some other Things.
Didn't the prototypes use the mobile version of the OMAP5 that got discontinued? That produced a lot less heat if I remember correctly.
 

TrashyMG

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Didn't the prototypes use the mobile version of the OMAP5 that got discontinued? That produced a lot less heat if I remember correctly.
No it used the same SoC as we currently use the OMAP5432. The mobile version OMAP5430 from what I could tell never made it to the public in any form.
 

Askarus

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What @ingoreis said.
My old prototype has no thermal solution at all.
That said, it only runs at 1GHz, so it won't overheat.

For gaming on the other hand I would want to have the best cooling possible as taxing games very likely may overheat the SoC.

Compared to any GPD gaming device the Pyra has the advantage of not needing an active cooling.
Improving that is always great :)
 

hns

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Didn't the prototypes use the mobile version of the OMAP5 that got discontinued? That produced a lot less heat if I remember correctly.
It was planned to use it but it never went to mass production... So we never did see a sample chip.
The main difference would have been that it could have used lower power DRAM. But it would just have been the same processor chip in a different (smaller) package. So heat production would not have been different.
 

ingoreis

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I realy like this Thread..so many Pictures of an opened Pyra and Ideas ho to cool it little better.
NVME Heatsink...wow great Idea..i think i do that too and it look nice for me.

This Thread show you Pictures for thinking about Future Pyra Mods or Ideas for a Pyra Docking Station.
 
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