A bunch of pictures


What heat problem? So far no problem has been shown to exist or found to be probable as far as I'm aware. Please correct me if one has presented itself.
Well, I get near critical CPU heat levels on the devboard and it's tiny heatsink.. I thought I had a restarting problem due to heat, but now I think that may because a 1.5A Pandora PS wasn't cutting it... However applying a small fan on the heatsink puts it somewhere more tolerable..


I do have a mess of things hitched to the board, however I do notice the heatsink does get very hot even idle with nothing plugged in.

20140730_183412.jpg
 
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Um... well, the metal case is irrelevant here, since it uses the case as huge heatsink and the other heatsink doesn't do anything to lead the heat out of the case...?
 
What heat problem? So far no problem has been shown to exist or found to be probable as far as I'm aware. Please correct me if one has presented itself.
We just discuss some theoretical stuff, better now than to late. ;) Imagine nobody would think onto an possible heat problem, the device is built and after that it turns out that the SoC melts itself inside the case, would be bad, right? I always try to think onto every possible issue BEFORE anything happens and I'm sure I'm not the only one that does so. :)
ED already explained how heat will be dissipated - from CPU throughout the whole PCB, then to the case then to the outside world. At least that is how I understood him.
Yes, I've read that but the step from the PCB to "outside of the world" is not that clear imho, at least if nobody wants holes or external heatsinks. The case itself does not help much beacuse it's just plastic.
Um... well, the metal case is irrelevant here, since it uses the case as huge heatsink and the other heatsink doesn't do anything to lead the heat out of the case...?
The one case is partly carbon but yes, metal case helps to reduce the problem, especialy if the case is designed as huge heatsink. ^^
Well, all I can suggest is an variation of Askarus' idea to guide the heat (from the PCB) out of the case IF this is needed. But of course the best would be if the Pyra just does not produce that much heat, at least it's still an ARM which are designed for small devices without any heatsinks.

Coppercooler.jpg
 
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What heat problem? So far no problem has been shown to exist or found to be probable as far as I'm aware. Please correct me if one has presented itself.
We just discuss some theoretical stuff, better now than to late. ;) Imagine nobody would think onto an possible heat problem, the device is built and after that it turns out that the SoC melts itself inside the case, would be bad, right? I always try to think onto every possible issue BEFORE anything happens and I'm sure I'm not the only one that does so. :)
ED already explained how heat will be dissipated - from CPU throughout the whole PCB, then to the case then to the outside world. At least that is how I understood him.
Yes, I've read that but the step from the PCB to "outside of the world" is not that clear imho, at least if nobody wants holes or external heatsinks. The case itself does not help much beacuse it's just plastic.
Um... well, the metal case is irrelevant here, since it uses the case as huge heatsink and the other heatsink doesn't do anything to lead the heat out of the case...?
The one case is partly carbon but yes, metal case helps to reduce the problem, especialy if the case is designed as huge heatsink. ^^

Well, all I can suggest is an variation of Askarus' idea to guide the heat (from the PCB) out of the case IF this is needed. But of course the best would be if the Pyra just does not produce that much heat, at least it's still an ARM which are designed for small devices without any heatsinks.
That picture is exactly what I thought of.

Simply couldn't paint it that nice and didn't mention the small pipes.

I hat that in mind for a long time now.

Thanks a lot for making a good picture.

Would be a pain for me to make that.
 
Those holes won't help much, as mentioned before!

The surface outside of the case is too small to have a real effect!

It will probably cool down everything by 1 or 2°C.
 
Those holes won't help much, as mentioned before!


The surface outside of the case is too small to have a real effect!


It will probably cool down everything by 1 or 2°C.

Ok, if you say it won't help I have an other idea.

How good does the LCD-Cable transport heat?

As it's connected to the Rotator chip board inside the lid it might help a lot more if we would find a way to transport the heat there as well.

We could increase the size of the lid board and almost double the area the head could spread.

Maybe we could even make a second "heat cable".

If we could use the area of the whole lid as well this should be enough cooling I think.
 
Well, I get near critical CPU heat levels on the devboard and it's tiny heatsink.. I thought I had a restarting problem due to heat, but now I think that may because a 1.5A Pandora PS wasn't cutting it... However applying a small fan on the heatsink puts it somewhere more tolerable..
Thanks for sharing this. How is ED's setup different? Didn't he say we wouldn't need much of a heatsink at all?
We just discuss some theoretical stuff, better now than to late. ;) Imagine nobody would think onto an possible heat problem, the device is built and after that it turns out that the SoC melts itself inside the case, would be bad, right? I always try to think onto every possible issue BEFORE anything happens and I'm sure I'm not the only one that does so. :)
Yes, it is good to consider things early, but then get actual data before acting on it. What we need is measurements telling use if the problem exists at all, how bad is it and what kind of a solution we need to counter it. Proactively countering a non-issue serves only to complicate the build and cause unnecessary compromises.
By all means, try to THINK about the issues before they happen, but only ACT upon them if needed. It's not entirely fitting, but the quote "premature optimization is the root of all evil" certainly has an analogy here.
 
That picture is exactly what I thought of.


Simply couldn't paint it that nice and didn't mention the small pipes.


I hat that in mind for a long time now.


Thanks a lot for making a good picture.


Would be a pain for me to make that.
Well, you described it good enough for me to make such an sketch. ^^ And also thanks to Autodesk 123D Design, it is really nice to use and can generate faster results than Blender. Try it out, it's free Software :)


However, I have no clue how to connect the internal SoC to the external heatsink it would need a real tiny heatpipe or at least a flat metal ribbon that is flat enough to fit.

By all means, try to THINK about the issues before they happen, but only ACT upon them if needed. It's not entirely fitting, but the quote "premature optimization is the root of all evil" certainly has an analogy here.
Lol, nice phrase, never heared of it. :D  But I actualy like to think onto every possible event long before I even start something, I really hate surprises of all kind, especialy bad surprises. So I always calculate every possible and maybe impossible effect an action can have, just to be more prepared and less pissed when something happens.  Sounds stupid but at least it reduces the "bad surprise" factor alot.   :ph34r:
 
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Thanks for sharing this. How is ED's setup different? Didn't he say we wouldn't need much of a heatsink at all?
  Well without airflow the Heatsink on the devboard is pretty useless, It may drop the temperature 5-10C.. It runs hot, but not over the critical mark from my observation.. Another thing to consider is there isn't any CPU frequency throttling setup like the Pandora yet in the OS.. I can change it manually between 500MHz, 1GHz and 1.5GHz but nothing in between..


aTc noticed some similar heating situations as I have.
 
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That picture is exactly what I thought of.


Simply couldn't paint it that nice and didn't mention the small pipes.


I hat that in mind for a long time now.


Thanks a lot for making a good picture.


Would be a pain for me to make that.
Well, you described it good enough for me to make such an sketch. ^^ And also thanks to Autodesk 123D Design, it is really nice to use and can generate faster results than Blender. Try it out, it's free Software :)


However, I have no clue how to connect the internal SoC to the external heatsink it would need a real tiny heatpipe or at least a flat metal ribbon that is flat enough to fit.
We'll find a way to make a convincing suggestion :) .

Let's make the daughter board as big as possible.

Just the board with nothing on it and the planned metal layer inside.

So it spreads above the other smaller parts around it.

And I still wonder if there's a way to spread the heat to the lid as well.
 
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Well without airflow the Heatsink on the devboard is pretty useless, It may drop the temperature 5-10C.. It runs hot, but not over the critical mark from my observation.. Another thing to consider is there isn't any CPU frequency throttling setup like the Pandora yet in the OS.. I can change it manually between 500MHz, 1GHz and 1.5GHz but nothing in between..


aTc noticed some similar heating situations as I have.
From an OMAP5 tech sheet: "Industrial temperature qualification (-40 to +85°C)"  at least the SoC has some decent tolerances. ^^"

http://newscenter.ti.com/2012-11-12-New-OMAP-5-processor-based-modules-spur-easier-faster-industrial-designs
 
From an OMAP5 tech sheet: "Industrial temperature qualification (-40 to +85°C)" at least the SoC has some decent tolerances. ^^" http://newscenter.ti...ustrial-designs
Well It's running a bit hotter than that.
 
It won't work like that, that's the problem.

Heat evenly distributes on a heat sink.

Without a heat sink, the SoC might have 110C.

With a 5x5cm heatsink, it might go down to 80C evenly distributed on the heatsink.

With a 10x10cm heatsink, it might go down to 50C evenly distributed on the heatsink.

...stuff about holes in a case and a fan...
Heat distributes evenly into a heat sink - and if it has nowhere to go, does not stop increasing in temp.

The SoC might have 110C at 5 minutes run time.

Using the heat sink it might be 50C at 5 minutes run time - but unless it's transported to the air or hands, it isn't going to stop there. A heat sink alone only draws the problem out longer.

Can you show me a picture of a PC which has a passive heatsink with holes in the case to let out the heat?

The only passive ones I know are simply heatsinks that are fully inside of the device.
Not holes, but I can show you several with heat sinks and external radiators.http://www.cappuccinopc.com/slimpro-sp675fp_fanless_mini_pc.asp

http://www.logicsupply.com/computers/feature/fanless/

The Shuttle box in this example appears to use vent holes, but likely an aluminum case too:

http://www.makeuseof.com/tag/5-silent-fanless-mini-pcs-that-will-save-you-money/

Um... well, the metal case is irrelevant here, since it uses the case as huge heatsink and the other heatsink doesn't do anything to lead the heat out of the case...?
The case is plastic or plastic with reinforcing fibers right?
Expanded Polystyrene (Coffee Cup) has a thermal conductivity of around 0.03W/m*K

Fibre reinforced plastic has a thermal conductivity of around 0.5W/m*K.

Granite rock is around 2W/m*K.

Aluminum is around 210W/m*K.

Copper is around 390W/m*K.

Diamond is 1000W/m*K.

With all due respect, I think you're completely missing the ideas being presented.

We're talking about using a heat sink that exits the case to be a combined heat sink AND radiator.

Askarus' idea would have an additional thick layer of copper in/on the main board connected to a copper/air radiant surface hidden in the hinge.

My idea would be to have a thin aluminum heat sink/transport sandwiched between the SoC and the battery that comes out the front of the device under the SD cards and wraps down and back to the battery door. It then has around 10CM^2 of surface area outside of the case to dissipate the heat from the SoC and the battery.

Either idea uses a substance with high thermal conductivity to draw heat into itself and an exposed surface outside of the case to radiate it to the surroundings.

From the mini-table above, you'll notice that aluminum is approximately 800 times better at transporting heat than the case plastics can be. Put another way, 1cm^2 of exposed (out of case) aluminum surface can do a similar job of dissipating heat from the SoC as 800cm^2 of plastic surface area.

Copper doubles that. However without proper sealants it will oxidize and turn green and loose some of it's radiator capacity.

No, we're not going to suggest using Diamond.

The flap/tongue/wrap of aluminum from between the SoC and battery, out the front under the SD slots, then wrapping back around the front edge of the bottom case should yield 5cm by 3cm or 10-15cm^2 of aluminum-air radiator. That's the equivalent of >8,000cm^2 of case plastics or roughly a square surface nearly a meter on a side.

A heat sink grants time - if there is nowhere to let the heat out, that time is limited.

Those holes won't help much, as mentioned before!

The surface outside of the case is too small to have a real effect!

It will probably cool down everything by 1 or 2°C.
Again, I think you're far overestimating the thermal conductivity of case plastics and far underestimating the thermal conductivity of copper and aluminum.

It's orders of magnitude in difference.
 
From an OMAP5 tech sheet: "Industrial temperature qualification (-40 to +85°C)" at least the SoC has some decent tolerances. ^^" http://newscenter.ti...ustrial-designs
Well It's running a bit hotter than that.
Really? Uh... then Houston, we have a problem. :-||"

@ Grench, thanks for explaining, you found good words to describe the situation. :)  An Metal Case would be the best solution it seems but of course also the most expencive. I hope there will be a cheap solution for cooling the SoC, ED mentioned more copper in the PCB, would be an good first step indeed but also sounds expencive and complex.
 
From an OMAP5 tech sheet: "Industrial temperature qualification (-40 to +85°C)" at least the SoC has some decent tolerances. ^^" http://newscenter.ti...ustrial-designs
Well It's running a bit hotter than that.
 Really? Uh... then Houston, we have a problem. :-||"

@ Grench, thanks for explaining, you found good words to describe the situation. :)  An Metal Case would be the best solution it seems but of course also the most expencive. I hope there will be a cheap solution for cooling the SoC, ED mentioned more copper in the PCB, would be an good first step indeed but also sounds expencive and complex.
This might help on understanding variance of thermal conductivity by materials - good reference:

http://en.wikipedia.org/wiki/List_of_thermal_conductivities

We don't need the whole case to be metal. We would just need a piece of metal that crosses over the outside wall of the case. Askarus's is a copper radiator under the hinge (good). Mine is a piece of aluminum coming out the front to a flat heat exchanger (good). We're concerned about ED's idea of a heat sink in a sealed and relatively well insulated box.

Askarus's idea from the picture with the fins/bumps on it probably has 1cm by 10cm of copper surface area if flattened. It's a pretty darn good idea IF we can get the heat from the SoC on the opposite side of the board piped up to that radiator. 10cm^2 copper is roughly about the equivalent of 20cm^2 aluminum is roughly about the equivalent of a section of case plastics 1.1M (Meter!) on a side.
 
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From an OMAP5 tech sheet: "Industrial temperature qualification (-40 to +85°C)" at least the SoC has some decent tolerances. ^^" http://newscenter.ti...ustrial-designs
Well It's running a bit hotter than that.
Really? Uh... then Houston, we have a problem. :-||"
The internal sensor is reporting crazy temperatures on load that would be enough to cook food, I can only hope it's wrong..It runs stable for me though.
 
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@ Grench, thanks for explaining, you found good words to describe the situation. :) An Metal Case would be the best solution it seems but of course also the most expencive. I hope there will be a cheap solution for cooling the SoC, ED mentioned more copper in the PCB, would be an good first step indeed but also sounds expencive and complex.
Agree.

An other idea.

We have the stylus hole.

Maybe that could be uses as well.

It's an other hole on the case we could use for "free" if we would find a way to make it usable.

Askarus's idea from the picture with the fins/bumps on it probably has 1cm by 10cm of copper surface area if flattened. It's a pretty darn good idea IF we can get the heat from the SoC on the opposite side of the board piped up to that radiator. 10cm^2 copper is roughly about the equivalent of 20cm^2 aluminum is roughly about the equivalent of a section of case plastics 1.1M (Meter!) on a side.

I don't see any problem here.

AFAIK it's planned that the processor is connected to both boards (only s#touches the big one).

Only problem might be to find a goos place to solder the copper "bridge".

Mine is a piece of aluminum coming out the front to a flat heat exchanger (good).
I can't imagine ho to that to the board.

It must be soldered or use thermal paste to be maximal effective.

Any 3D model graphic like I did?
 
From an OMAP5 tech sheet: "Industrial temperature qualification (-40 to +85°C)" at least the SoC has some decent tolerances. ^^" http://newscenter.ti...ustrial-designs
Well It's running a bit hotter than that.
Really? Uh... then Houston, we have a problem. :-||"
The internal sensor is reporting crazy temperatures on load that would be enough to cook food, I can only hope it's wrong..
It runs stable though.
Is 80° that high?

Don't know but my laptop reports more than that under full load (Intel core 2 Extreme T9900).

GPU died twice while gaming but not CPU.
 
^ Well EvilDragon was mentioning temperatures at 100C.. It may be bogus.. but it does get pretty hot. The heatsink on the devboard is garbage, so anything may be an improvement.
 
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