[sdiy] Looking for a mini rotary encoder with very low torque (servo type).. Found another better solution..

[Jean-Pierre Desrochers]

Here is a followup of my last request to find a small rotary encoder
to read paper scrolling speed on my MIDI Piano Roll Player project..

 

The solution I found is to use a very small wheel (used in model cars)
that has plastic rim and a real rubber tire.
The one I use has 28mm (outside diameter).

I mounted it on a small 3/32in shaft with a small 14mm diameter
optical wheel (8 holes per turn) that turns over
an opto-interrupter sensor.
The complete setup is glued on a small PCB cut in 2 parts
with a home made hinge made of brass tubing.
A small spring keeps a small tension against both 
the tire and the moving paper take up spool.

The opto sensor send pulses to my PIC micro
to analyse the actual paper speed to correct it if nessary.

Voilà !
I’m now making some modifications to my program

And doing some tests.
By the way, I design the 14mm opto wheel using my PCB CAD software.

 

Some pictures of what I said are showing below.
Thanks for all your previous support about thjis project!
JP

 

********************************************************************

> I'm looking for a very small (20mm or less body diameter)

> rotary encoder with very low torque (servo type).

> The low torque shaft is needed because it will turn by means

> of a small wheel with rubber sides that will be put against a moving surface, turn and 'follow'

> the moving surface.. no slipping allowed !

> 

> The precision of steps/turn is not important.

> But the higher will be best..

> 

> I was thinking of using a dismantled PC mouse (rubber ball type)

> and use one of the two  X/Y optical rotary encoders, but these PC mice

> nowadays are hard to find.. So.

> 

> I checked Digikey and Mouser but they have encoder too big

> for my uses..

> The smaller I found has 20mm in diameter..

> https://www.digikey.ca/en/products/detail/nidec-components-corporation/RES20D-50-201-1/6469509

> 

> Any suggestions ?

> 

> 

 

Pictures of the actual opto-sensor setup:

 









-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20250105/888e7539/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.png
Type: image/png
Size: 65770 bytes
Desc: not available
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20250105/888e7539/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image008.jpg
Type: image/jpeg
Size: 36925 bytes
Desc: not available
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20250105/888e7539/attachment.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image009.jpg
Type: image/jpeg
Size: 42694 bytes
Desc: not available
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20250105/888e7539/attachment-0001.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image010.jpg
Type: image/jpeg
Size: 39764 bytes
Desc: not available
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20250105/888e7539/attachment-0002.jpg>