[sdiy] Expo question and unrelated dumb matrix idea

[Tom Arnold]

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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 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
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