[sdiy] replacing step incrementor/decrementor with continuous pot

[Paul Maddox]

Rob/Emmanuel,

> Shouldn't be to hard using a rotary encoder with a bit of logic to
recreate the up and down from the increment/decrement
> or whatever of the rotary encoder.
> Basically the rotary encoder has 3 digital output which varies in gray
code I think, so you can determine if you
> increment or decrement or don't change using probably only logic gates.

I hate Gray code...
pah, and I HATE rotary encoders... Im useing 5 on my polywave (now you see
why I hate them)
ok it works like this (warning BAD ASCII diagram looming)

For clockwise you get;-

outputA  __~~__~~__
outputB  ~__~~__~~_

For anti clockwise you get

outputA  ~__~~__~~_
outputB  __~~__~~__

So what you can see is that ONE channel leads the other depending on which
way its turned...
Now you need debounceing (this rotary pot is nothing more than two SPST
switchs on a dial)..
If you want to convert this into two button pushes without software you can
do it useing a Dtype flipflop
and a little logic (or gate IIRC)...


feed one channel (say output A) in the clock of the FF
and the other into the D...

take outputA and this becomes your clock pulse.
the output of the FF now becomes your direction...
Note though, this ISNT debounced!!!
you could always add a cap across the switch and cheap :-)

This with a little logic and a 4066 should be able to replace the switchs on
the front panel.

Paul Maddox

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