[sdiy] rotary switches in general

[Theo]

Think instead of a pot it would be easier to hook up a rotary encoder (or
push buttons) to a up/down counter.
(channel A to clock and channel B to up/down will do)
I also like to use 4017 with one push button, switching 4066 and 4051 as
needed.
You need a 4017 variant with ST clock input to debounce though.

Theo


----- Original Message -----
From: Tim Parkhurst <tparkhurst at siliconbandwidth.com>
To: 'mark s' <djarum11 at mindspring.com>; <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, August 11, 2004 12:16 AM
Subject: RE: [sdiy] rotary switches in general


> Build quality is going to be the biggest difference. The price may also be
> set by how popular a switch is (more popular = higher production numbers =
> lower unit cost).
>
> One alternative that I've seen used by others is to take a pot, hook it up
> as a voltage divider and run the voltage into a simple (2, 3 or 4 bit) A/D
> converter. The output of the A/D can then control an analog
> switch/multiplexer, transistors, or even relays. You'll need to add some
> indicator LEDs to provide user feedback, but this is relatively easy. A
very
> simple "A/D" solution would be to use the LM3914 bar graph chip (10
outputs
> = approx 3.5 bit resolution). This gives you the option of "bar" or "dot"
> modes, and the outputs can be easily grouped together if you need fewer
than
> 10 positions. Given the cost of quality rotary switches, the A/D setup
> should be cost competitive, plus you now have a voltage controlled switch!
>
> Here are some relevant URLs:
>
> LM3914 data sheet
> http://www.national.com/pf/LM/LM3914.html
>
> I first saw the concept used here:
> http://www.musicsynthesizer.com/Circuitry/sequencers_page.htm
>
> There are some other examples of how to run +/-10V signal through a 4051,
> but I can't find them right now. It can be done however, and I'll dig them
> up if you really need it.
>
>
> Cheers!
>
> Tim (less popular/higher cost) Servo
>
> "Imagination is more important than knowledge." - Albert Einstein
>
>
>
>
> > -----Original Message-----
> > From: mark s [mailto:djarum11 at mindspring.com]
> > Sent: Monday, August 09, 2004 11:53 PM
> > To: synth-diy at dropmix.xs4all.nl
> > Subject: [sdiy] rotary switches in general
> >
> >
> > would someone care to elaborate on the differences between a $1.50
rotary
> > switch and a $10-$20 one? (USD)  is this a 'hearable' difference or a
> > mechanical one or both ??
> >
> > mark scetta
> >
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