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<div class="moz-cite-prefix">Hi JP</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">There's definitely no reason you can't
try it with one sensor.</div>
<div class="moz-cite-prefix">It depends on how your positioning
mechanism works and how proportionally it needs to deal with paper
position errors.</div>
<div class="moz-cite-prefix">Certainly, if you do it with minimal
hardware and you are confident that the software can deal with it
all, please do what you feel will work best for you.</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">Best wishes</div>
<div class="moz-cite-prefix"><br>
</div>
<div class="moz-cite-prefix">Gerry</div>
<div class="moz-cite-prefix"><br>
</div>
<p><br>
</p>
<p>On 10/04/2023 01:20, Jean-Pierre Desrochers wrote:</p>
<blockquote type="cite"
cite="mid:004c01d96b42$49fd2240$ddf766c0$@oricom.ca">
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<p class="MsoPlainText"><span lang="EN-CA">Hi again Gerry,</span><b><i><span
lang="EN-CA"><o:p></o:p></span></i></b></p>
<p class="MsoPlainText"><b><i><span lang="EN-CA"><o:p> </o:p></span></i></b></p>
<p class="MsoPlainText"><b><i><span lang="EN-CA">> Hi JP<o:p></o:p></span></i></b></p>
<p class="MsoPlainText"><b><i><span lang="EN-CA">> Another
attempt at attaching the image. This time as a gif.<o:p></o:p></span></i></b></p>
<p class="MsoPlainText"><b><i><span lang="EN-CA">> Hope you
can open it.<o:p></o:p></span></i></b></p>
<p class="MsoPlainText"><span lang="EN-CA">It worked !<o:p></o:p></span></p>
<p class="MsoPlainText"><span lang="EN-CA"><o:p> </o:p></span></p>
<p class="MsoPlainText"><b><i><span lang="EN-CA">> I think if
you use two sensors, you have the increased accuracy
that comes from two signals when balanced.<o:p></o:p></span></i></b></p>
<p class="MsoPlainText"><b><i><span lang="EN-CA">> 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. <o:p></o:p></span></i></b></p>
<p class="MsoPlainText"><b><i><span lang="EN-CA">> Using two
sensors, each would be equally affected by temperature
& voltage variations and this would reduce the
system error.<o:p></o:p></span></i></b></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA">The idea of using only one sensor was without
any opamp at all.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA">Only the sensor’s open collector output to a
micro-controller..<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA">Here again are my thoughts on that:<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">But what about using only one sensor at the
right paper side??</span><span lang="EN-CA"><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</span><span lang="EN-CA"><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</span><span lang="EN-CA"><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..</span><span
lang="EN-CA"><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.. </span><o:p></o:p></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>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"
lang="EN-CA"><o:p> </o:p></span></p>
<div style="border:none;border-left:solid blue 1.5pt;padding:0cm
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<div>
<div style="border:none;border-top:solid #E1E1E1
1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="FR">De :</span></b><span
lang="FR"> Gerry Murray <a class="moz-txt-link-rfc2396E" href="mailto:synthimuse@gmail.com"><synthimuse@gmail.com></a> <br>
<b>Envoyé :</b> 9 avril 2023 19:16<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>
<div>
<p class="MsoNormal">Another attempt at attaching the image.
This time as a gif.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Hope you can open it.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">I think if you use two sensors, you
have the increased accuracy that comes from two signals
when balanced.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">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. <o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Using two sensors, each would be
equally affected by temperature & voltage variations
and this would reduce the system error.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">That's just the way it seems to me.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Happy to hear others views.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Best regards<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 10/04/2023 00:03, Jean-Pierre
Desrochers wrote:<o:p></o:p></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span
style="mso-fareast-language:EN-US">Clever idea too !</span><o:p></o:p></p>
<p class="MsoNormal"><span
style="mso-fareast-language:EN-US"> </span><o:p></o:p></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??</span><o:p></o:p></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</span><o:p></o:p></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</span><o:p></o:p></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..</span><o:p></o:p></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..</span><o:p></o:p></p>
<p class="MsoNormal"><span
style="mso-fareast-language:EN-US" lang="EN-CA"> </span><o:p></o:p></p>
<p class="MsoNormal"><span
style="mso-fareast-language:EN-US" lang="EN-CA"> </span><o:p></o:p></p>
<div style="border:none;border-left:solid blue
1.5pt;padding:0cm 0cm 0cm 4.0pt">
<div>
<div style="border:none;border-top:solid #E1E1E1
1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="FR">De :</span></b><span
lang="FR"> The SynthiMuse <a
href="mailto:synthimuse@gmail.com"
moz-do-not-send="true"><synthimuse@gmail.com></a>
<br>
<b>Envoyé :</b> 9 avril 2023 17:27<br>
<b>À :</b> Jean-Pierre Desrochers <a
href="mailto:jpdesroc@oricom.ca"
moz-do-not-send="true"><jpdesroc@oricom.ca></a><br>
<b>Cc :</b> synth-diy mailing list <a
href="mailto:synth-diy@synth-diy.org"
moz-do-not-send="true"><synth-diy@synth-diy.org></a><br>
<b>Objet :</b> Re: [sdiy] My Player piano roll
project... refining my design</span><o:p></o:p></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>
<blockquote style="border:none;border-left:solid #CCCCCC
1.0pt;padding:0cm 0cm 0cm
6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0cm;margin-bottom:5.0pt">
<div>
<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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</blockquote>
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<p><o:p> </o:p></p>
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