[Cryptech Core] starting to plan a novena test run

[Павел Шатов]

On 28.04.2015 10:55, Joachim Strömbergson wrote:
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> Aloha!
>
> Randy Bush wrote:
>> [ non-core will be bored by this bikeshed ]
>>
>>>> pain in the butt.  but you are probably right.  but i really hope
>>>> it is off the shelf and the box in which to ship it plus novena
>>>> is trivially available.  otherwise, this becomes a project in
>>>> itself.
>>> Yes, I'm thinking a very simple, plastic off the shelf box for
>>> electronics. Should just be a question of searching for a couple,
>>> buying them to test and then decide.
>>
>> paul, would you advise trying to buy a bunch of what you used?  if
>> so, what are they and who sells them?
>
> Paul actually retrofitted an enclosure for a SOHO router. But I think
> Pavel had some suggestions on boxes.

Speaking of mechanical stuff, Novena board has two flaws:

1) It has very large capacitors on its bottom side. They are huge, and 
you can easily tear them away, if you accidentally rub the board against 
the table. These are bulk capacitors, their placement is not that 
critical, bunnie should have used two smaller low-profile capacitors in 
parallel instead of these monsters. Protective enclosure is highly 
recommended because of that.

2) Mounting holes have very thin annular rings (marked with red 
circles). If you ever fitted a motherboard into a computer case, you've 
seen, how thick annular rings around mounting holes on a typical 
motherboard are. I don't know, why bunnie made them so thin. You will 
have to use screws with very small heads because of that.

Novena PCB itself is 150x121 mm. Some connectors extend beyond this 
outline, so our case should have at least about 160x130 mm of internal 
space. Height should be about 25 mm. We also need to secure the board in 
the case somehow. Distance from mounting holes to board edges is 3 mm. 
I'm afraid, we won't be able to find an off the shelf box with mounting 
bosses, that will fit Novena mounting holes. I can suggest buying a 
generic enclose without bosses and securing the board with either 
standoffs or pillars 
(http://www.elpac.de/prodimages/large/lpr_8301_ff_250.jpg)

You can read this report to better understand what we'll have to do: 
https://www.sparkfun.com/tutorials/38

As you see, this guy bought a case with mounting bosses, but they didn't 
fit mounting holes in his PCB, so he glued new standoffs. We can either 
buy a case without bosses, or cut them away, if they interfere with new 
standoffs.

I can suggest this case, for example: http://www.gainta.com/en/g763.html 
They don't have a nice picture on their website, you can have a look at 
it here: http://www.rct.ru/catalog/enclosure-case-box/g763.html

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With best regards,
Pavel Shatov