[sdiy] sin/cos pot

[Liam D]

Thanks! I remember coming across this style of pot a while back when tinkering with an alesis ion. That synth used about 30 of these plus a few regular pots all muxed down to 8 ADC channels. The service manual is on the web if anyones interested in the schematic. I always thought these would be cool parts to design with but I could never find a supplier for them.

cheers,

Liam
> On Jul 10, 2017, at 9:50 AM, Rick Jansen <rick.jansen at xs4all.nl> wrote:
> 
> Very useful! Thanks for this, I had never seen it before.
> 
> rick
> 
> On 10 Jul 2017, at 13:12, Ullrich Peter <Peter.Ullrich at kapsch.net <mailto:Peter.Ullrich at kapsch.net>> wrote:
> 
>> Hi!
>>  
>> Maybe the Bourns ACE Encoder could fit here: absolute encoder, 128 states per revolution, no hard steps
>> https://www.bourns.com/pdfs/ace.pdf <https://www.bourns.com/pdfs/ace.pdf>
>>  
>> about 5pounds
>> http://uk.farnell.com/bourns/eaw0j-b24-ae0128l/encoder-rotary-128pos-8-bit/dp/9358234 <http://uk.farnell.com/bourns/eaw0j-b24-ae0128l/encoder-rotary-128pos-8-bit/dp/9358234>
>>  
>> Youtube:
>> https://www.youtube.com/watch?v=MrPW8QGmlrM <https://www.youtube.com/watch?v=MrPW8QGmlrM>
>>  
>> https://www.youtube.com/watch?v=44-XMo730wI <https://www.youtube.com/watch?v=44-XMo730wI>
>>  
>>  
>> Ciao
>> Peter
>>  
>> http://www.ullrich.at.tt <http://www.ullrich.at.tt/>       (My homepage)
>> http://synpro.heimat.eu/datadial.htm <http://synpro.heimat.eu/datadial.htm>   (Synth addon)
>> http://rc100-usb.at.tt/ <http://rc100-usb.at.tt/>    (Roland sampler tool)
>>  
>>  
>>  
>> Von: Synth-diy [mailto:synth-diy-bounces at synth-diy.org <mailto:synth-diy-bounces at synth-diy.org>] Im Auftrag von paula at synth.net <mailto:paula at synth.net>
>> Gesendet: Montag, 10. Juli 2017 12:51
>> An: Julian Schmidt <elfenjunge at gmx.net <mailto:elfenjunge at gmx.net>>
>> Cc: synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>
>> Betreff: Re: [sdiy] sin/cos pot
>>  
>> Issues I see with a sin/cos pot;
>> 
>> Use of 2 x ADC channels (more expensive than logic inputs)
>> 
>> Slightly more complex software for reading/processing the sin/cos outputs.
>> 
>> Advantge; you get an absolute position.
>> 
>>  
>> 
>> if you want more resolution from a regular grey code rotary encoder. you can use double edge triggering.
>> 
>> So instead of just picking the rising edge on one channel, use both edges, this will give you 48PPQN with a 24PPQN encoder.
>> 
>> I guess, though not tested, you could go a step further and use edge detection on both channels and both edges on both channels giving you 96PPQN from a 24PPQN encoder, though I would expect switch bounce to cause more of a problem at this resolution.
>> 
>> Downside; no absolute position.
>> 
>>  
>> 
>> Paula
>> 
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>> 
>> On 2017-07-10 11:31, Julian Schmidt wrote:
>> 
>> I also found them at www.adimpex.it <http://www.adimpex.it/> for 1.15€/pcs. but they have a minimum order amount of 200€ :-/
>> still looking for a better sample source.
>> 
>> Am 10.07.2017 um 12:09 schrieb Michael Zacherl:
>> On 9.Jul 2017, at 12:42 , Julian Schmidt <elfenjunge at gmx.net> <mailto:elfenjunge at gmx.net> wrote:
>>  
>> Anybody has an idea what the part number for the continuous alpha pots is?
>> I just asked the other day for an encoder alternative with higher resolution, they would be great!
>> Maybe I'd have to ask my distributor in taiwan about them.
>> Thanks for sharing, didn't know such a pot exists.
>> How would you tell the direction of the movement?
>>  
>> BTW, $15 ... hm ... needs quantities I'd guess ... 
>> https://www.aliexpress.com/item/1pcs-ALPHA-RV112FF-40B3N-22F-0B10K-Encoder-360-degree-turn-gain-potentiometer/32751858615.html <https://www.aliexpress.com/item/1pcs-ALPHA-RV112FF-40B3N-22F-0B10K-Encoder-360-degree-turn-gain-potentiometer/32751858615.html>
>>  
>> Thanks, Michael.
>>  
>>  
>>  
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