Re: modifiable backplane with sockets?

Don Y <blockedofcourse@foo.invalid> writes:

>
If you are using perfboard, you will be constrained as to the locations
and placements of devices (based on the "holes").  If you can stick
with DIP packages, this could be OK.  SMT might be a stretch to fabricate
like this (esp if you didn't want to be forever "patching" it)
>

The first analog computer used just DIP and through-hole components. I'm
open-minded at this point on DIP vs SMT — but I don't really know how to
prototype with SMT components and the stuff I've read
scratching/drilling divides into copper boards doesn't sound very
practical. But maybe I should try something new. Copper-clad perfboard
sounds like it might be a practical, inexpensive approach.

>
How about splaying the backplane out "like a circuit board" instead of
like a set of card slots?  Imagine "postage stamp" modules arragned
side by side, row after row (i.e., in a small grid) such that you
could see and access all of the components WHILE it is assembled.
Flip it over to do point to point wiring, as required.
>
There, you might be able to come up with a different mechanincal
design for the modules -- one that mimics a DIP (with a row
of pins on each "end") and plugs into a set of contacts
similarly arranged.
>
This does the "major, intermodule" wiring on the backplane and still
leaves you the freedom to tweak any interconnections WITHIN a
module AND OBSERVE THE ENTIRE CIRCUIT WHILE POWERED.
>
Size is just a tradeoff between how delicate you want the modules
to be and the number thereof.

This basic idea sounds appealing.

>
The real downside risk would be if *a* post snapped while the others
were intact.  You'd have to remove the entire connector just to
restore that post's functionality.
>
[If the entire "site" was unused when the break happened, you just
replace the whole connector.]
>

So, on the "postage stamp" board, how do you think I should do the
interconnections? Wire wrap between posts? Or just do a solder bridge
over to the next perfboard hole and connect a wire to that?

--
Christopher Howard