[sdiy] rotary switches in general

[Scott Gravenhorst]

"Roy J. Tellason" <rtellason at blazenet.net> wrote:
>On Tuesday 10 August 2004 06:16 pm, Tim Parkhurst wrote:
>
>> 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).
>
>Now *that* is kinda nifty!  :-)
>
>> This gives you the option of "bar" or "dot" modes,
>
>I guess the "dot" mode would be more useful in this context,  mostly?
>
>> 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!
>
><...>
>
>> 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.
>
>I'd be a little curious about this since the usual max power supply on those 
>is 15V,  and +/-10V would appear to need a wider range,  unless I'm 
>misunderstanding something here?


You made me look.  Here it is from our friend René Schmitz:

http://web.lan/wget_sites/www.uni-bonn.de/~uzs159/switch.html








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