[sdiy] My Player piano roll project... refining my design

Jean-Pierre Desrochers jpdesroc at oricom.ca
Sun Apr 9 18:21:08 CEST 2023


Very good idea.

If I understand correctly their would be 2 sensors close to each other

but set a little apart from each ones. (But on one of the two paper sides only)

If so there would be some kind of detected ‘notch’ or ‘peak’

to tell the paper is correctly placed right ?

But when this peak or notch disappears how can I know which direction to move the paper

and correct its position ?

I would need the same tandem on the other paper edge.. ?




De : Synth-diy <mailto:synth-diy-bounces at synth-diy.org> De la part de Gerry Murray via Synth-diy

Envoyé : 9 avril 2023 11:20

À : mailto:synth-diy at synth-diy.org

Objet : Re: [sdiy] My Player piano roll project... refining my design




I would recommend two of these sensors operated in linear mode, with a small difference in their physical position and invert the signal from one of them.

>From these two signals you would get a 'detent' differential signal that would tell you the lateral error and allow you to adjust the horizontal position of the paper more accurately.


Best wishes




On 09/04/2023 16:09, Jean-Pierre Desrochers wrote:

Hi all again,

I’m still trying to refine my design and working on

the paper centering process circuit.

So far I’m using the tracker bar edge’s holes to detect

left/right paper movements while playing the rolls.

Those who are at the paper’s edge sides. 

The system works pretty well 

but still some rolls lacks of centering correction.

SO I want to do some tests using Photointerrupters - Slot Type – with open collector Outputs.

Like those types:



I’m trying to select the best accurate one to detect paper edges

not the overall paper cutting the IR beam..

Any idea of the best specifications to pick one ?



De : Synth-diy mailto:synth-diy-bounces at synth-diy.org De la part de Jean-Pierre Desrochers

Envoyé : 23 février 2023 17:31

À : mailto:Synth-diy at synth-diy.org

Objet : [sdiy] My Player piano roll project... a small video demo for you..

Importance : Faible


I’m not done yet with this project but this is promissing..




I let the piano roll play its song while filming.. around 4:00 duration.

Enjoy !




Synth-diy mailing list

mailto:Synth-diy at synth-diy.org


Selling or trading? Use mailto:marketplace at synth-diy.org


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20230409/1bf2791a/attachment.htm>

More information about the Synth-diy mailing list