[sdiy] rotary encoder?

[Paul Maddox]

Mark,

   you know it wouldn't be that hard to decode a rotary encoder in  
logic and hook it's output upto an up/down counter.

  Though it would take considerably more than the one chip you'd need  
if you used a micro :-)

   Let's see, you'd need an edge triggered latch.
one pin of the rotary encoder connected to the input of the latch  
(with pull up)
the other output of the encoder connected to the trigger in of the  
latch (with pull up)
the "common" pin would need to connect to ground.

   You then need a simple bit of logic (some nand gates?) to turn this  
into two pulse trains to drive a 74hc193 binary up/down counter.

Paul

On 8 Jan 2009, at 01:44, mark verbos wrote:

> While I'm sure that would work fine, I have NO IDEA how to program a  
> microcontroller, so that's out!
>
>
> Mark
>
>
>
> On Jan 7, 2009, at 8:34 PM, Matthew Smith wrote:
>
>> Quoth mark verbos at 2009-01-08 11:32...
>>> I have a situation where I'd like a 12 position rotary switch to   
>>> output a parallel 4 bit digital word. I searched absolute rotary   
>>> encoder at mouser and they're $88. Isn't there a cheap part out  
>>> there  that does that? Obviously, I could use 50 diodes to make a  
>>> regular  rotary switch do that...
>>
>> How about a cheap encoder that does 2-bit Gray code?  You could use  
>> it with a cheap microcontroller to put out your 4-bit code.   
>> (Probably cheaper to use an MCU than discrete logic.)
>>
>> I've seen several listed in China on eBay like this:
>>
>> <http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=400020432401>
>>
>> I've got some similar for a MIDI control surface I'm designing.   
>> I'm using pots and ADCs for single-byte controllers and encoders  
>> for dual-byte controllers.
>>
>> Cheers
>>
>> M
>>
>> -- 
>> Matthew Smith
>> Smiffytech - Technology Consulting & Web Application Development
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