Michael Meeuwisse wrote:
And I'm
working with a Chinese board maker on single copper plus conductive
ink 98% SMT boards with few holes that
are cheap and good. For high speed paths, a separately made ground
plane adhered to bottom of the board
and solder connected by some through holes or wrap around edge clips
might be needed, but the cost of
a PCI card with gold plated edged connector could be BOM + $5 in
volume of 50, higher $$'s if lower numbers,
lower $$'s if higher numbers.
I'm not entirely following you here, but are you suggesting a single
layer design? In that case, forget it.
No. 2 layers, one copper, one conductive silver ink 40 milliohms per square.
Usually you can identify traces that can stand some resistance, then make those
be silver ink jumpers.
UV cure acrylic "paint" is put down as insulator material, then ink over that
makes a 2-layer topology on one side additively and with no hole drilling, and
ends up cheap and good.
Voltage planes, if desired, need to be added as a separate board adhered
on/soldered on.
For a pure SMT board zone, a ground plane can be copper adhesive tape and some
soldering
to connect well, but breaks in it because tape is thinner than a board would
not work well
unless butted together neatly and soldered over -- if pressure-adhesive copper
will stay put for that...
If you find a plated through 4 layer board is needed with ground planes, forget
the $1 bare board price I said...
It was nail-biting annoying to
get it to fit on two layers, I am somewhat convinced it can't be done
with any less.
Also, when I speak of some people, I currently mean 5 cards counted for.
I'm personally not interested in 45 spare ones. :) If you can realise
the proposed price point however this might change.
It would have to change. It's not worth starting until there is a batch size
of twenty.
But you could help with a layout in pcb free-open-tool and data format, and
great postscript and gerber output.
What is your layout done in?
Can your board be done with < 300 SMT pads, 105 cm sq, some paths used
for jumping over others
with 1 or 2 Ohms resistance, the rest heavy etched copper? If so,
maybe I can be your supplier
now that the Euro is so expensive, (USD is so cheap).
We could trim a little at the edges I assume, but not much.
It's just a known price point. more area --> more money is all.
I'm not sure
how much cm sq it's right now. I do know it's currently at 310-ish vias,
so <300 is probably doable.
No, just slightly more money is all.
I'm not offering to fab for you, but to make and sell an open-hardware
product
Right now it's 33 different parts, of which the first one (the FPGA) is
already $25 each, or $22 per 25 from digikey.
So... what's the total BOM cost? Take that and add about $5 if batch size is
50 add maybe $10 if
batch is only 20 boards.
Also, I went for the €150,- pricepoint for much the same reason as
you're saying that you can boot-strap your operations
I'm talking about using the profit from this to pay for devel time on others
when I say bootstrapping.
This product is a very low volume kind....to bootstrap to some higher kinds I
am working on.
If you can push the price down considerably, I wouldn't
mind buying one from you instead of figuring out everything myself.
Cheers,
Michael
www.projectvga.org
Sure. Best thing is to find 20 30 units buyers. They'll need to pay in
advance.
The existing layout you have could accelerate things. Even a postscript of it
that I can make a light grey
image of and put in background while I redo layout in geda pcb.
Part of my selling strategy for open-hardware-eval boards
is they are a "better" eval board, TAPR open hardware license and geda pcb and
gschem docs are ready to
add onto, not just start from zero and enter all
the footprints and schematic symbols for a long while before even starting to
add new design details.
having geda gschem and pcb docs for the boards makes them a speedup tool for
developers, hobbyists.
Thanks,
John Griessen
PS the same thing could be done for OGD1, except the layout is so much,
probably needs 6 weeks
and a prototype test and bugfix run of 3 boards, I can't see
starting without running a spreadsheet on how many prepaid buyers there are and
if parts cold be bought
in >100 lots for most parts. I don't know if the TT folks are OK with
me being the hardware supplier since they propose to be the supplier at present. The OGD1 probably needs to be 4 layer. It has
lots of chips, lots of connectors...it's harder, more of a hurdle to be a product.
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