[sdiy] Substitute for pin matrixes? Probability list update 2.

[cheater cheater]

Kyle,
a 4051 is an 8 channel multiplexer which means it can can only make 4
connections (with 8 ends) - correct me if I'm wrong?

Thanks
D.

On Sun, Jan 24, 2010 at 21:54, Kyle Stephens <lightburnx at yahoo.com> wrote:
> Here's a solution with only two pots for an 8x8 matrix:
>
> An X pot, and a Y pot, both wired as voltage dividers, each running into an 8-bit ADC. Each bit address intersects with an AND gate (quad AND, need 4 - and one input is for the X-axis, the other the Y-axis), the output of which turns on 1/8 of a 4051 (2x of those for 16 connections), with one switch 'pole' connected to a point on one axis, and the other pole to its respective spot on the other axis. If you need some visual indicator, a decoder and numerical LED array will get you there (more simply, if taking more space, two rows of LEDs tapped off of each address lines works too).
>
> If you need more than 8x8 connections, you can just cascade an ADC with a binary weighted out and op amps, needing much, much less than 8 bits per 'bank' (vis-a-vis a VCDO), depending on how many connections we're talking here. (might want a coarse/fine pot setup at that point).
>
> (8x8)^2 = 4096 possibilities (that's a Hans Zimmer-class synth!).
> More reasonably, say (2x8)^2 = 256.
>
> At its simplest as said, it's just two pots - if available real estate is an issue, this takes care of that.
>
> You could even make the patching voltage controlled, putting CVs into the ADCs, ooh...just a thought.
>
> The off-the-top-of-my-head-estimated bill for this would be, with surplus parts and let's say $0.50/most ICs...
>
> 2x pot = $3
> 2x ADC = $7
> 4x AND = $2
> 2x 4051 = $1
> 2x decoder = $2 (optional)
> 2x LED array = $6 (optional)
>
> $15-23. Cheap?
>
>
> _Kyle
>
> --- On Sun, 1/24/10, karl dalen <dalenkarl at yahoo.se> wrote:
>
>> From: karl dalen <dalenkarl at yahoo.se>
>> Subject: Re: [sdiy] Substitute for pin matrixes? Probability list update 2.
>> To: synth-diy at dropmix.xs4all.nl
>> Date: Sunday, January 24, 2010, 9:20 AM
>> Turning stones for something
>> cheaper(dead cheap)then a Gillimetti matrix:
>>
>> 1: Aligator clips on wire mesh as array.
>> 2: Sub miniature SPDT arrays.
>> 3: Toy railway/mechano sub sub bananas arrays.
>> 4: 2.5mm tele arrays.
>> 5: 3.5mm tele arrays.
>> 6: 4mm bananas arrays.
>> 7: Upside down IDC array resistor or wire as cross
>> connects.
>> 8. Turned IC holders arrays.
>> 9:  Pin lists arrays.
>> 10: Miniature push button arrays.
>> 11: Veroboard layers as arrays, with bridge shorting
>> between.
>> 12: MT8816 and others, 4066, serial latches, MCU etc.
>> 13: Latching Hall sensor arrays, controlling muxes.
>> 14: Relay arrays, klicketi klack sound on its own.
>> 15: Buchla paper solder punch card holders pluggable
>> something.
>> 16: A gigantic array of pots.
>> 17: Fuse holder array.
>> 18: Automatic fuse array.
>> 19: Rims of plastic Lab plates arranged in arrays.
>> 20: Standing sub miniature USB connectors, can carry 4
>> signals each.
>> 19: Replace the analog shit with digital DSP shit for plain
>> convenience?
>> 20: LDR Matrix with card with holes blocking a light
>> source.
>> 21: Spark gap and other high voltage switches, watch out
>> for your safety.
>>
>> At the moment im out of ideas so i just post a updated
>> probability
>> list as a reference for folks to know what has been
>> discussed so far!
>> Not saying you shouldn't evolve over it again, perhaps you
>> find
>> something this time you didn't find the first?
>>
>> KD
>>
>>
>>
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>
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