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<div class="moz-cite-prefix">Hi JP</div>
<div class="moz-cite-prefix">Another attempt at attaching the image.
This time as a gif.</div>
<div class="moz-cite-prefix">Hope you can open it.</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">I think if you use two sensors, you
have the increased accuracy that comes from two signals when
balanced.</div>
<div class="moz-cite-prefix">If you use one sensor, you would be
comparing the signal to a reference voltage but the sensor signal
could vary with temperature or supply variations. <br>
</div>
<div class="moz-cite-prefix">Using two sensors, each would be
equally affected by temperature & voltage variations and this
would reduce the system error.</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">That's just the way it seems to me.</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">Happy to hear others views.</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">Best regards</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">Gerry</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">On 10/04/2023 00:03, Jean-Pierre
Desrochers wrote:<br>
</div>
<blockquote type="cite"
cite="mid:003b01d96b37$8cd06060$a6712120$@oricom.ca">
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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Clever
idea too !<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA">But what about using only one sensor at the
right paper side??<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA">If the output is low (IR beam passes , Paper
too far left) move the paper right<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA">If the output is high (IR beam hidden, Paper
too far right) move the paper left<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA">This way the centering will continually look
for the output ‘transition’ position<br>
to ‘consider’ the paper is at the right position..<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA">But ONLY at the transition position.<br>
But doing so the centering will ALWAYS be working.. but that
could be OK<br>
for a very precise centering.. Hmmm..<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="FR">De :</span></b><span
lang="FR"> The SynthiMuse <a class="moz-txt-link-rfc2396E" href="mailto:synthimuse@gmail.com"><synthimuse@gmail.com></a>
<br>
<b>Envoyé :</b> 9 avril 2023 17:27<br>
<b>À :</b> Jean-Pierre Desrochers
<a class="moz-txt-link-rfc2396E" href="mailto:jpdesroc@oricom.ca"><jpdesroc@oricom.ca></a><br>
<b>Cc :</b> synth-diy mailing list
<a class="moz-txt-link-rfc2396E" href="mailto:synth-diy@synth-diy.org"><synth-diy@synth-diy.org></a><br>
<b>Objet :</b> Re: [sdiy] My Player piano roll
project... refining my design<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">Hi JP<o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">I should have been clearer earlier on
so I've attached a scribbled image of my idea.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">There's no need to invert one of the
signals. You just need to get nice linear values from 2
sensors and put them into a differential amplifier. This
will give you a DC value that will tell you the position
error and you can use it to drive the correction
mechanism.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Obviously, if the signal from the two
sensors are equal, then the paper is perfectly centred.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">I hope this helps.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Best wishes <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Gerry<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">On Sun, 9 Apr 2023, 17:24 Jean-Pierre
Desrochers, <<a href="mailto:jpdesroc@oricom.ca"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">jpdesroc@oricom.ca</a>>
wrote:<o:p></o:p></p>
</div>
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<div>
<p> <o:p></o:p></p>
<p><span lang="EN-CA">Very good idea.</span><o:p></o:p></p>
<p><span lang="EN-CA">If I understand correctly their
would be 2 sensors close to each other</span><o:p></o:p></p>
<p><span lang="EN-CA">but set a little apart from each
ones. (But on one of the two paper sides only)</span><o:p></o:p></p>
<p><span lang="EN-CA">If so there would be some kind
of detected ‘notch’ or ‘peak’</span><o:p></o:p></p>
<p><span lang="EN-CA">to tell the paper is correctly
placed right ?</span><o:p></o:p></p>
<p><span lang="EN-CA">But when this peak or notch
disappears how can I know which direction to move
the paper</span><o:p></o:p></p>
<p><span lang="EN-CA">and correct its position ?</span><o:p></o:p></p>
<p><span lang="EN-CA">I would need the same tandem on
the other paper edge.. ?</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">******************************************************************************</span><o:p></o:p></p>
<p>De : Synth-diy <mailto:<a
href="mailto:synth-diy-bounces@synth-diy.org"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">synth-diy-bounces@synth-diy.org</a>>
De la part de Gerry Murray via Synth-diy<o:p></o:p></p>
<p>Envoyé : 9 avril 2023 11:20<o:p></o:p></p>
<p>À : mailto:<a href="mailto:synth-diy@synth-diy.org"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">synth-diy@synth-diy.org</a><o:p></o:p></p>
<p><span lang="EN-CA">Objet : Re: [sdiy] My Player
piano roll project... refining my design</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">Hi JP</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">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.</span><o:p></o:p></p>
<p><span lang="EN-CA">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.</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">Best wishes</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">Gerry</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">On 09/04/2023 16:09, Jean-Pierre
Desrochers wrote:</span><o:p></o:p></p>
<p><span lang="EN-CA">Hi all again,</span><o:p></o:p></p>
<p><span lang="EN-CA">I’m still trying to refine my
design and working on</span><o:p></o:p></p>
<p><span lang="EN-CA">the paper centering process
circuit.</span><o:p></o:p></p>
<p><span lang="EN-CA">So far I’m using the tracker bar
edge’s holes to detect</span><o:p></o:p></p>
<p><span lang="EN-CA">left/right paper movements while
playing the rolls.</span><o:p></o:p></p>
<p><span lang="EN-CA">Those who are at the paper’s
edge sides. </span><o:p></o:p></p>
<p><span lang="EN-CA">The system works pretty well </span><o:p></o:p></p>
<p><span lang="EN-CA">but still some rolls lacks of
centering correction.</span><o:p></o:p></p>
<p><span lang="EN-CA">SO I want to do some tests using
Photointerrupters - Slot Type – with open
collector Outputs.</span><o:p></o:p></p>
<p><span lang="EN-CA">Like those types:</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">I’m trying to select the best
accurate one to detect paper edges</span><o:p></o:p></p>
<p><span lang="EN-CA">not the overall paper cutting
the IR beam..</span><o:p></o:p></p>
<p><span lang="EN-CA">Any idea of the best
specifications to pick one ?</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p>De : Synth-diy mailto:<a
href="mailto:synth-diy-bounces@synth-diy.org"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">synth-diy-bounces@synth-diy.org</a>
De la part de Jean-Pierre Desrochers<o:p></o:p></p>
<p>Envoyé : 23 février 2023 17:31<o:p></o:p></p>
<p>À : mailto:<a href="mailto:Synth-diy@synth-diy.org"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">Synth-diy@synth-diy.org</a><o:p></o:p></p>
<p><span lang="EN-CA">Objet : [sdiy] My Player piano
roll project... a small video demo for you..</span><o:p></o:p></p>
<p><span lang="EN-CA">Importance : Faible</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">I’m not done yet with this
project but this is promissing..</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA"><a
href="https://www.youtube.com/watch?v=K7xXYqCB0AY"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://www.youtube.com/watch?v=K7xXYqCB0AY</a></span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">I let the piano roll play its
song while filming.. around 4:00 duration.</span><o:p></o:p></p>
<p><span lang="EN-CA">Enjoy !</span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA"> </span><o:p></o:p></p>
<p><span lang="EN-CA">_______________________________________________</span><o:p></o:p></p>
<p><span lang="EN-CA">Synth-diy mailing list</span><o:p></o:p></p>
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