[Arm-netbook] EOMA Micro Engineering Board case built

[joem]

On Mon, 2013-08-12 at 14:07 -0500, Christopher Thomas wrote:
> 
> 
> On Mon, Aug 12, 2013 at 3:34 AM, joem <joem at martindale-electric.co.uk>
> wrote:
>         On Mon, 2013-08-12 at 00:43 +0100, luke.leighton wrote:
>         > awesome joe - i've linked it here:
>         >
>         http://rhombus-tech.net/community_ideas/micro_engineering_board/
>         >
>         > btw remember you'll need to do some mods to the MEB to make
>         it useable.
>         
>         
>         No problem - do you have a pdf of circuit diagram?
>         I'm looking at R1 and it appears a (yellow) C is fitted (see
>         the photos
>         http://www.gplsquared.com/eoma_boot/eoma_boot.html )
>         [I can peer review the circuit if you would like me to.]
>         
>         Notes to Chris:
>         1. C1 is over rated - use smaller voltage for smaller cap to
>         reduce
>         board height - get it below the ethernet socket height to
>         build array.
>         2. Leave more space around hole near DC socket to allow for
>         spacer to be
>         fitted. I want to build a parallel array.
>         3. Hey Chris mi old harty, how many orders do you need to
>         start next
>         batch? (I can buy max 4 more to build my EOMA supercomputer
>         array.)
> 
> 
> I have a long-winded reply coming for when I hit 10 orders. I need 4
> (yours will do). 

Email total inc postage privately and I send it this evening.

> As for the next batch, there are two "teams" I know of (I am one)
> currently making revisions to the MEB schematic, we're working on
> collaborating to prevent duplicating efforts, so you might want to
> wait until then. 
>
> 
> That said, regarding the components, I didn't design the first MEB,
> so I did not think to review all of the components.  Regarding height
> and sizes. We were working on converting things over to SMD to aid in
> automated assembly, and to reduce overall size. To still allow users
> to solder by hand, we were considering using 1206 size components as
> you don't need a microscope/magnification to solder them and they're
> rather plentiful and easy to handle. 

I used to think like that - but a decent pair or Bernstein 5-054
(pricey) sharp pointed tweezers easily addresses components down to
0805. They handle 0603 as well, but inconvenient - need good eyesight
and much more steady hand.

> 
> After we get the changes made, would you mind running over the
> schematic and see if you can find any hang-ups?  We could definitely
> use some peer-review considering our PCB designer left (I've been
> interviewing candidates all last week.) 

No problem.
[FYI - I'm also doing a KiCAD version containing 68 pin PCMCIA socket +
1.6mm DDR socket + 1mm 200 pin SODIMM socket. But I have to order from
CN the first two items in bulk and they have to arrive for dimension
checks - about 1 month total delay.]