[time-nuts] Form Factor and such, Big Picture
Hal Murray
hmurray at megapathdsl.net
Thu Dec 23 00:40:29 UTC 2010
I think I'm missing the big picture. What sort of things are people
interested in building? Will they all be a reasonable fit with a single Form
Factor, Bus, and whatever?
I've been thinking of something like a mother board with FPGA that would fit
in something like the Hammond boxes. The idea is that the FPGA is the part
that's hard for me because I can't handle soldering BGAs. All the front-end
analog stuff would go on a daughter card.
The hardware interface between the mother/daughter cards is just a row (or 3)
of pins/sockets for 0.1 inch connectors. (or anything similar) Software
interface is TBD. It might make sense to publish a "standard" interface for
some application so the same firmware on the motherboard would work for
various front ends.
It might make sense to put an ARM next to the FPGA. You can get a lot of CPU
for $10-20.
I'm not sure what the back end sould look like. I'd be happy with USB or
Serial. They are dumb/simple and don't require massive protocol stacks. I
could live with Ethernet, but it really raises the bar for getting off the
ground. (I'm not interested in running a web server on my toys. All I want
is simple command/response. I'll put the web server on a PC that has access
to all the archived data.)
It might make sense to have a back-end daughter card.
With that sort of setup, I think I could build a 5370 class box that I could
use for long term data collection. Does that seem reasonable?
I don't need the full flexibility of the 5370 front end. I'm willing to use
jumpers or a soldering iron for things like AC vs DC coupling and 50 ohm
termination.
On the other hand, how much board space would a spectrum analyzer take?
Should we be discussing 2 sizes of projects?
--
These are my opinions, not necessarily my employer's. I hate spam.
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