Paralleling a momentary Sw. through 20' of cable ?

Started by petemoore, August 03, 2010, 10:41:54 AM

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petemoore

  Digitech Jamman Stereo Record button is a momentary switch.
  Any additional circuit info welcome.
  Is there a quick 'n dirty way to test without drawing too much current ?...put a 2 conductor wire to the 2 contacts, run them 10' one way through the parallel/remote switch, then 10' back into unit.
  Is there a sure-fire way [such as buffer the switch supply circuit voltage] to make a remote switch for this momentary.
  If it can be made to work for this one, the next one [UNDO] would be the same...I presume.
  Record/Undo instead of reverse and tempo. First thing I ever want to do with a recording device is start recording, second thing would be stop recording, one of the last things I'd want as a remote control would be reverse control.
Convention creates following, following creates convention.

petemoore

  Sorry for the bump, just been wonderin' pretty hard about it.
Convention creates following, following creates convention.

cpm

if its switching a logic level, say: pull to gnd, whats the worst that can happen with a long cable?

wire resitance might be significant. Assumming its a momentary gnd connection for a signal, and the signal has a pull-up resistor, your cable resistance is acting as a voltage divider that would raise the logic-off voltage a bit over gnd. It depends on the pull-up resistor value (may be 10k, 100k, whatever). If it stays below a safe threshold (as of logic leves) shoudnt be much problem.

Hides-His-Eyes

just breadboard it up with some low value resistors (1R? 10R?) and small value cermaic capacitors to simulate the cable, and see what kind of resistance and capacitance you can get away with. Cheap cable is about 30pf a metre isn't it? and the resistance of 6m is only going to be a few ohms.

No reason why it shouldn't work that I can think of.

petemoore

  Simple enough !
  Cable I have, ST. jack and doesn't-yet-workalike footswitch already, [probably quicker than working up a simulator] trick is...I'll open it up and see if I can figure out what the trick is.
  It works alike, the switch tests, the diodes test [all switches work and the anodes connect, not much left to re-de-bug-a bugy bugulate on.
  Already I can't figure out why the workalike doesn't change the silly parameters Tempo and Reverse...need to make the footpedal work alike first I think.
Convention creates following, following creates convention.

Hides-His-Eyes

yeah, the lack of openness in commercially bought stuff is really frustrating when you have to go back after being used to knowing every detail about a circuit- Maybe when I'm an old timer the kids on here will be sharing ways to extract algorithms from digital ICs  :P