[sdiy] Substitute for pin matrixes?

[karl dalen]

ASSI <Stromeko at nexgo.de>

> I said on the outset that the leaf type contacts would work
> better for this and my comments were directed to those.  The
> turned pins are designed for only a few matings cycles with
> very good retention, your  result confirms that.

Ah, i see, i misunderstood you, i thought you meant turned ones.
I have been testing various leaf ones now and results are very
diverse, anything from 10 times and breaking to over 150 but bent
and rather bad contact dependeing on manufacturer, chinese low cost
are worst! So im not to convinced about them either.

> I don't know how the solderless breadboards are speced, but
> I have yet to wear one out (except if I try and force square pegs from
> PCB pin  strips into them, that will kill that contact right away or
> at least  make it unuseable with anything other than square
> pegs). 

I have the same experience so i went out to my storage to fetch one spare
i had to see if it was possible to solder a cable to one of the metal lanes
and it did.

There are two kind of lab plates as i call them one with round hole and
one with square hole, both takes round resistor legs, why its square i
dont know but disassembled they both have two rounded leaf/tongue
contactors.

The are cheap, (5-7euro) compared to pin lists or IDC's one can buy a single strip that gives 640 contact points in rows of two 64's with
5 ins and 5 outs on each row, thats a lot! The tedious thing are
soldering 128 cables to these metallic strips, it would have a breeze
if the manufacturer had bent one end down so one could solder it to a
PCB! I made graph over such a panel, it do look professional to.

Theres a link i to such one in one of my earlier posts.

>I've seen 
> the contact strips from those boards on a surplus sale
> somewhere a few 
> years ago, don't know if you can still get them.

They are in stock ,new at most the regular suspects!
 
> For much better contacts, check this out: http://www.hypertac.com
> Their test system connectors are something to marvel
> over.  Certainly not cheap, but they give you 30,000 mating cycles. 
> More interesting should be the stamped contacts that might provide a >venue  to get  matrix receptables with a decent number of mating cycles at
> bearable cost.

I had a look but could not find test system connectors?
Everything looks very expensive there.

> Oh, and reeds might not be such a bad idea after all if you
> operate  them with moving permanent magnets via a push-push
> mechanism (like a biro).  Or just use 100 actual biros from
> some office supply sale and 
> have them push on a matrix of micro switches.

Whats a biro? All i got was a ballpoint pen?!
> 
> Going back a century or so (nothing wrong with that!) you
> could pull a  Hollerith and use an array of pogo-pins and a cardboard
> with holes  where you want a connection and no holes where you
> don't.  If you're  old enough, you might still know this as a punch
> card.  Combined with  todays SMT you might even be able to provide >multiple resistances per  matrix point if you can get the holes punched >precisely  enough.

Solderless veroboard would replace that!

KD



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