[sdiy] dumb matrix idea

[Harry Bissell Jr]

The AMP part numbers for the sockets are
380635
380598

they would take a .040 pin or smaller
check them out. Price ??? who knows its
AMP ain't it...

H^) harry



--- Scott Gravenhorst <music.maker at gte.net> wrote:
> Yes and the inverse function can be implemented with
> an opamp with a diode in
> the negative feedback loop.  I've never tried it,
> but I'm told it's anything
> but accurate and has all of the temperature
> wonderfulness that an expo
> converter suffers.
> 
> AN-30 (application note 30) which is about log
> converters might interest you.
> 
> David Moylan <dave at westphila.net> wrote:
> >Inverse of expo is log.
> >
> >Dave
> >
> >Tom Arnold wrote:
> >
> >>First, the expo question.
> >>
> >>Is there such a beast as an inverse expo
> converter, or is there a different
> >>name for this that I'm not thinking of at 2:30am? 
> I'm doing a pot to
> >>current->voltage converter and the responce I'm
> getting acts very Expo (
> >>lots of movement for not much voltage change and
> them whammo ).  The pot
> >>*is* linear.
> >>Unfortunatly I'm trying not to modify the control
> the pot is in, so
> >>connecting it across the supply rails and taking a
> voltage from the wiper
> >>isnt an option.  I dont need to be exact, just
> need to compensate in a rough
> >>way for the crappy curve I'm seeing.
> >>
> >>Next, the dumb matrix idea.
> >>
> >>Since I obviously have too much spare time and too
> few projects, I played
> >>with something else tonight too.  I want to build
> a small pin matrix with
> >>small being the operative word ( I'd like 15x15 in
> about 2" square ).  The
> >>idea I tried that actually seems to work is taking
> strips of machinepin
> >>sockets for SIP IC's, trimming the pins off then
> grinding the bottom lightly
> >>with a dremel until I hit the cavity.  I was
> afraid the contacts might pop
> >>out the bottom once it was open but in this case (
> Augat sockets ) they did
> >>not.  Now an actual sewing pin goes right through
> the top socket and can be
> >>lined up on a second set of SIP sockets which are
> unmodifed to provide the
> >>second contact.  Its less work then it sounds
> although I only made a 5x5 as
> >>my test matrix.  May be cool for matrix patching a
> noise box or something.
> >>
> >>Next run to the surplus places I'm going to try
> and find some older
> >>microprocessor sockets that are solid pins across
> the bottom unstead of
> >>having an empty area around the die as this would
> give me a solid top and
> >>bottom structure to play with.
> >>
> >>I did mention it was a dumb matrix idea... but it
> may be a fun toy for
> >>someone.
> >>
> >>  
> >>
> >
> 
>
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> -- Scott Gravenhorst | LegoManiac / Lego Trains /
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