Raspberry Pi 2 is unstable.

I would be more concerned about the RasPi 2 building up heat on the bottom while it's sitting on top of that bag.  After it's been running a while, pick up the board and see how hot the bag is.  DRAM can get quite warm depending on what it's doing.

I run my RasPi Model B (v1.0 PCB with 256MB DRAM) vertically mounted so I can get air flow on both sides.  That prevents it from overheating, especially the USB/LAN chip which otherwise gets very hot due to design problems that were fixed in the 2.0 PCB.

I would be more concerned about the RasPi 2 building up heat on the bottom while it's sitting on top of that bag.  After it's been running a while, pick up the board and see how hot the bag is.  DRAM can get quite warm depending on what it's doing.

I run my RasPi Model B (v1.0 PCB with 256MB DRAM) vertically mounted so I can get air flow on both sides.  That prevents it from overheating, especially the USB/LAN chip which otherwise gets very hot due to design problems that were fixed in the 2.0 PCB.

I agree, Except that "touching the bag" is not going to tell you how hot it has become. Humans think they can tell how hot something is, but in reality they feel how much heat is transferred from the object to their skin. The heat capacity of a bag is so small that you won't feel it as hot even if it is hotter than boiling temperature.

Feel the DRAM chip when positioned as John suggests, then feel it after half an hour being "insulated" by lying on the bag.

I'm not too afraid that it'll overheat, so I would dare the plastic bag construction. In fact I have my media center raspberry pi on such a bag on a piece of styrofoam (very good thermal insulator) at home. It's an old pi, so no RAM on the bottom siide. But: it's an old 'pi,  so it dissipates heat instead of using a switching regulator......

I have a bag with EXACTLY the "this is an antistatic bag" print on it like in the datasheet linked above. It could very well be a bag that one of my 'pi's came in. But I have been unable to measure any of the conductivity claims from the datasheet. I measure "infinity" ohms until I accidentally put the measuring pins together... Does anybody have a suggestion on how to make contact with the conductive layer in the middle? (I'm assuming "user error" instead of "cheap fake".....).

Note: Sticking the measuring pins through the bag does not work.

Note: We have found "conductive foam" with a measurable resistance.

Note; we have also found "looks like conductive foam" with a VERY high resistance (> 10^4 more than the other foam).

Note: we've torn the bag apart at the seams. This results in the bag delaminating. We THINK we see three different "levels" of delamination, which means that at least one of the surfaces should be the conductive layer. In fact even if there are only two delamination interfaces, with four layers and knowing the conductive layer is not on the outside you should always be able to find the aluminium. Aargh! Scratch that: At the seam there are of course 8 layers. Three non-conductive delamination interfaces /are/ available in that case (one inside each stack-of-four layers, and one in between the two stacks).

Roger

Not all bags are created equal.

Some bags have a coating on the inside film, others are multilayer with coatings facing in.

The life of the bag depends on it's design, and I've seen some shocking examples of 'over use' ...   ".. but we put it in an antistatic bag..."

Unfortunately the use of meter probes presents a very small surface area.

You should use two small squares to make the comparisons.

Luckily the bags supplied with the RPi (one from PRC and one from UK) use the same bag which is marked, so it was easy to verify.

There are different bags as well.

Some are dissipative and designed for conduction, while the majority are designed for Farady Shielding .... (as in these bags).

Good luck.

Mark

mcb1 wrote:

 

Roger

Not all bags are created equal.

Of course. But the bag I tested has exactly the print mentioned in the datasheet referenced above, the datasheet is said to refer to the bags that the 'pi ships in, and I got it from the pile where I put the bags that the pi comes in. So I'm quite confident that the bag I tested is the one in the datasheet. It has four layers, Three of which are insulators, and the last one is said to be aluminium with a resistance of 100 ohms for every square.

The bag had a marking

STATIC SHIELDING BAG

ANT010SSB

This bag is ROHS compliant.

I searched on ANT010SSB

I'm struggling to even make out the layers, so not sure how you could seperate them.

For the proper mats we had a clip that went through the layers.

Mark