A bunch of pictures

[hns]

Better make the heatsink as big as possible now.

For "as big as possible" there isn't much room anyways. And, the design is not yet in a stage where we can really estimate that (without running a 3D thermal simulation model like this: http://www.solidworks.com/sw/products/simulation/thermal-management.htm or https://www.youtube.com/watch?v=gXMQCDV8_Ew ) One problem is that we don't even know all parameters (dimensions, thermal conductivity, heat production) to feed into such a simulation model because some parts of the design are not yet stabilized. And we also have no access to Solid Works...

If anyone knows and is experienced to use a free&open tool (FreeCAD plugin?) for such thermal simulations we could give it a try.

 

[Inqui]

Connect it with the case and make alucases possible

 

[Binky]

^ So all the non-aluminium models had to have stricter processor throttling?

 

[fusion_power]

My suggestion for the heat issue:

The best and best way to bring heat outside the case would be the gap between Lid and Keyboard (between the hinges).

No one can touch it and you have quite some area to transport the heat outside the case.

How to do it?

The CPU is between Motherboard and CPU board.

Connect the CPU with the Motherboard.

Then on the motherboard make a metal bridge below the hinge.

It would only need to be soldered on the board twice (on its ends) and it's main body would be above the rumble motor and wonky chip everyone loves that much.

You know what I mean?

A metal bridge over the Parts on the front side which comes outside the Plastic part (keyboard) below the hinge.

Here it won't be a problem for anyone no matter how hot it gets.

Could this work?

I know what you mean. Nice idea, so the hot air could get out there at the gap through holes in the case, I made a sketch:

 

[Binky]

I think holes in the case would be a bad idea.

Dirt will get in.

It would be much better to put a small heatsink or similar there instead.

Also, holes are no good unless there's also somewhere for air to get in.

 

[rygD]

I think holes in the case would be a bad idea.

Dirt will get in.

It would be much better to put a small heatsink or similar there instead.

Also, holes are no good unless there's also somewhere for air to get in.

I was just about to say the same kind of thing (dust, invaluable pocket lint).

As for air input, how tight are we expecting the SD slots to be?

 

[Grench]

Mmm...  The issue is with how the SoC daughter board connects to the motherboard - it's horizontal left/right UNDER the motherboard with connectors on the left and right.

To get the heat up to the hinge area would require going to the back and up straight through the mess of connectors on the back.

The SoC is bounded on the left & right by it's own connectors.  Front & back by the SD slots and back ports.  Top by the motherboard itself.  Bottom by the battery.  It really is a little self contained box in a box.

If we want 'good' heat transfer, the heat sink needs to slip between the SoC daughterboard and the motherboard - which is dubious.

Maybe we can get 'acceptable' heat transfer by placing the heat sink on the back/battery side of the SoC - but then to where?  Front has SD slots, rear has ports.

The battery makes heat too, so we can't dump heat into it.

Almost has to be from between the SoC daughter board and battery then go left/right to the case edges and through.  Doesn't it?

 

[slaeshjag]

SD card holders could possibly work. Far away enough that flimsy heat transfers won't bring them near core tempterature, but close by enough that they might help dissapate some.

 

[fusion_power]

I think holes in the case would be a bad idea.


Dirt will get in.


It would be much better to put a small heatsink or similar there instead.


Also, holes are no good unless there's also somewhere for air to get in.

The whole case has holes everywhere actualy, it's not like it is sealed at all. And the open air holes could be covered with some thin filter underneeth.


A heatsink there would be under the holes of course but so or so the heat must be guided away from the SoC. Not sure how small heat pipes can be but these could be an solution.

SD card holders could possibly work. Far away enough that flimsy heat transfers won't bring them near core tempterature, but close by enough that they might help dissapate some.

And the possibility to melt the plastic SD cards, right?

 

[Askarus]

I think holes in the case would be a bad idea.

Dirt will get in.

It would be much better to put a small heatsink or similar there instead.

Also, holes are no good unless there's also somewhere for air to get in.

I don't want open holes.

There needs to be metal inside the holes.

That metall is connected via the main board with the CPU.

Not sure how small heat pipes can be but these could be an solution.

Exactly.

I want heat pipes in every hole.

As we can't put these pipes there directly (too many other parts) we need an other solution.

Made a quick schematic sketch.

 

[fusion_power]

Exactly.


I want heat pipes in every hole.


As we can't put these pipes there directly (too many other parts) we need an other solution.


Made a quick schematic sketch.

Technicaly, thats an single big hole which may affect the stability of the case there but I see your point, this also could work, especialy if this part has an structured (fluted) surface.


However, there would be still plastic around and above (hinge area of the lid) so the heat spreader shouldn't get to hot to avoid trouble. But so or so I have no idea how hot the OMAP5 can get and what existing cooling solutions are already made for devices with that chip, would be interesting to find out.

 

[Grench]

As to a radiator inside the back hinge - aesthetically pleasing, but you simply can't get there from here.

Scroll back to ED's pictures on page 1.  Look at the motherboard.  The side with the contact pads on it goes up.  The side with the components goes down.

There is simply no path from the bottom side with components on it (heaters) TO the hinge on the top/rear of the case.

Try the left/right/front/base ?

 

[Askarus]

As to a radiator inside the back hinge - aesthetically pleasing, but you simply can't get there from here.

Scroll back to ED's pictures on page 1.  Look at the motherboard.  The side with the contact pads on it goes up.  The side with the components goes down.

There is simply no path from the bottom side with components on it (heaters) TO the hinge on the top/rear of the case.

Try the left/right/front/base ?

You see the silver square on the mother board?

Here the processor will touch to the main board.

(Hope I'm informed right)

As long as you have contact to the mother board it doesn't matter where space is.

You build a bridge that can be connected to the mother board anywhere.

Connectors don't have to be on the side of the bridge.

You can place them anywhere.

There is no pressure or any other force.

What's below the surface doesn't matter much as long as something comes out below the hinge.

If the bridge is soldered let's say 1cm under the plastic.

Made a scetch.

As it's not visible there is no need for symmetry.

Also it can be connected anywhere on the board and go around every part that's disturbing it.

Anyone could make a 3D model?

GTA04, any way to make it like I suggested?

 

[TeDaDeS]

I've already done some tests and it seems we don't need much of a heatsink.

I wouldn't rely on that.
Maybe we want to upgrade the CUP and then we might need a bigger heatsink.


Better make the heatsink as big as possible now.

From products I've worked on this has always been some (small) kind of issue.


Indeed better to be prepared for the worst (reasonable margin) because it's just hard to fix when products are shipped.

 

[Silent-Hunter]

The hardware looks like it's coming along nicely, but how is the software doing?

 

[Glyph Reader]

The hardware looks like it's coming along nicely, but how is the software doing?

I know that they are/(have already?) setting up a mailing list for that stuff.

-Glyph Reader

 

[Grench]

As to a radiator inside the back hinge - aesthetically pleasing, but you simply can't get there from here.

Scroll back to ED's pictures on page 1.  Look at the motherboard.  The side with the contact pads on it goes up.  The side with the components goes down.

There is simply no path from the bottom side with components on it (heaters) TO the hinge on the top/rear of the case.

Try the left/right/front/base ?

 You see the silver square on the mother board?

Here the processor will touch to the main board.

(Hope I'm informed right)

As long as you have contact to the mother board it doesn't matter where space is.

You build a bridge that can be connected to the mother board anywhere.

Connectors don't have to be on the side of the bridge.

You can place them anywhere.

There is no pressure or any other force.

What's below the surface doesn't matter much as long as something comes out below the hinge.

If the bridge is soldered let's say 1cm under the plastic.

Made a scetch.

As it's not visible there is no need for symmetry.

Also it can be connected anywhere on the board and go around every part that's disturbing it.

Anyone could make a 3D model?

GTA04, any way to make it like I suggested?

The silver square on the corner of the main motherboard is for the 3G & GPS processor.

The SoC daughter board connects via the two front-back strips with the 'top' of the SoC pointed toward the main motherboard. It is between the SD slots and the rear ports.

Heat doesn't conduct quite like electrical signals. It requires 3 dimensional material volume, not just a metallic connection.

The main motherboard is already VERY dense. If you're wanting to use traces for heat transfer, (bad idea to start, but I'll run with it) you'll need a -lot- of surface area as the traces are only a 'few' atoms thick. Think thinner than the thinnest foil you can handle without ripping.

Slashjag's comment on the front SD slots made me think a bit more - and maybe onto something that could work.

How about an anodized aluminum sheet that feeds from between the SoC and the main board forwards between the SD slots and the battery (remember features are on the bottom of the board, keyboard on top) then out the front and fold UP (holes cut for SD cards) and over the front edge of the lower case nearly to the keyboard keys? Or, alternatively, it could go down the lower case front, wrap back around under the base to the battery door.

Either way it's a C bend in a piece of stamp-cut sheet aluminum. It's a heat sink and spreader and radiator.

 

[Yoyobuae]

Could the mainboard itself be used for heat transfer? Not sure how good is PCB material at heat transfer, but it seems like using the PCB itself would be a cheap/efficient solution.

Then the only thing needed is some thermal paste on top the SoC to achieve good thermal contact with the mainboard.

This is of course assuming the SoC doesn't generate extreme amounts of heat like a desktop PC CPU would.

 

[levi]

I don't know for sure, but PCB backing material is designed to be strongly non-conductive, and things that don't conduct electricity don't tend to conduct heat either for similar reasons.

 

[Grench]

Could the mainboard itself be used for heat transfer? Not sure how good is PCB material at heat transfer, but it seems like using the PCB itself would be a cheap/efficient solution.

Then the only thing needed is some thermal paste on top the SoC to achieve good thermal contact with the mainboard.

This is of course assuming the SoC doesn't generate extreme amounts of heat like a desktop PC CPU would.

Motherboard will likely have @ 0.0347mm thick traces.

http://www.pcbuniverse.com/pcbu-tech-tips.php?a=4

Heat transfer requires material to transfer through. Different materials transfer heat at different rates. Copper is very very good at transporting heat - BUT it will need some cross section to do it very efficiently.

http://www.physicsclassroom.com/class/thermalP/Lesson-1/Rates-of-Heat-Transfer

Using the 'window example' we would have copper traces instead of glass, 0.0347mm tall, 0.5cm wide and 5cm long (as a quick example).

30ga copper sheet metal is pretty thin at 0.318mm thick. However, substituting a piece of it 3cm wide and 5cm long in place for the above traces gives a much much larger cross section - and an equivalent greater heat transfer capability.

0.0347*5 = 0.1375mm^2 for traces

0.318*30 = 9.54mm^2 for a dedicated sink/transfer/radiator

Note that is right around 55 times the cross section - and 55 times the amount of heat that can be transported per time unit.

Using the motherboard as a heat sink is probably not viable.

Using a dedicated sheet of copper going from between the SoC and the motherboard, under the SD slots and out the front is viable, but would turn green and gunky from contact with sweating palms. Aluminum has over half the heat transfer capabilities of copper, is less bendy, costs a lot less and doesn't discolor which makes it a good choice.

30ga ~ 0.3mm is about three times the thickness of the walls of a soda can. Much thinner and it would be hard to keep it in the right shape.