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</o:shapelayout></xml><![endif]--></head><body lang=FR-CA link=blue vlink=purple style='word-wrap:break-word'><div class=WordSection1><p class=MsoPlainText>Here is a followup of my last request to find a small rotary encoder<br>to read paper scrolling speed on my MIDI Piano Roll Player project..<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>The solution I found is to use a very small wheel (used in model cars)<br>that has plastic rim and a real rubber tire.<br>The one I use has 28mm (outside diameter).<o:p></o:p></p><p class=MsoPlainText>I mounted it on a small 3/32in shaft with a small 14mm diameter<br>optical wheel (8 holes per turn) that turns over<br>an opto-interrupter sensor.<br>The complete setup is glued on a small PCB cut in 2 parts<br>with a home made hinge made of brass tubing.<br>A small spring keeps a small tension against both <br>the tire and the moving paper take up spool.<o:p></o:p></p><p class=MsoPlainText>The opto sensor send pulses to my PIC micro<br>to analyse the actual paper speed to correct it if nessary.<o:p></o:p></p><p class=MsoPlainText>Voilà !<br>I’m now making some modifications to my program<o:p></o:p></p><p class=MsoPlainText>And doing some tests.<br>By the way, I design the 14mm opto wheel using my PCB CAD software.<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>Some pictures of what I said are showing below.<br>Thanks for all your previous support about thjis project!<br>JP<o:p></o:p></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText>********************************************************************<o:p></o:p></p><p class=MsoPlainText>><i> I'm looking for a very small (20mm or less body diameter)<o:p></o:p></i></p><p class=MsoPlainText>><i> rotary encoder with very low torque (servo type).<o:p></o:p></i></p><p class=MsoPlainText>><i> The low torque shaft is needed because it will turn by means<o:p></o:p></i></p><p class=MsoPlainText>><i> of a small wheel with rubber sides that will be put against a moving surface, turn and 'follow'<o:p></o:p></i></p><p class=MsoPlainText>><i> the moving surface.. no slipping allowed !<o:p></o:p></i></p><p class=MsoPlainText>><i><o:p> </o:p></i></p><p class=MsoPlainText>><i> The precision of steps/turn is not important.<o:p></o:p></i></p><p class=MsoPlainText>><i> But the higher will be best..<o:p></o:p></i></p><p class=MsoPlainText>><i><o:p> </o:p></i></p><p class=MsoPlainText>><i> I was thinking of using a dismantled PC mouse (rubber ball type)<o:p></o:p></i></p><p class=MsoPlainText>><i> and use one of the two X/Y optical rotary encoders, but these PC mice<o:p></o:p></i></p><p class=MsoPlainText>><i> nowadays are hard to find.. So.<o:p></o:p></i></p><p class=MsoPlainText>><i><o:p> </o:p></i></p><p class=MsoPlainText>><i> I checked Digikey and Mouser but they have encoder too big<o:p></o:p></i></p><p class=MsoPlainText>><i> for my uses..<o:p></o:p></i></p><p class=MsoPlainText>><i> The smaller I found has 20mm in diameter..<o:p></o:p></i></p><p class=MsoPlainText>><i> <a href="https://www.digikey.ca/en/products/detail/nidec-components-corporation/RES20D-50-201-1/6469509">https://www.digikey.ca/en/products/detail/nidec-components-corporation/RES20D-50-201-1/6469509</a><o:p></o:p></i></p><p class=MsoPlainText>><i><o:p> </o:p></i></p><p class=MsoPlainText>><i> Any suggestions ?<o:p></o:p></i></p><p class=MsoPlainText>><i><o:p> </o:p></i></p><p class=MsoPlainText>><i><o:p> </o:p></i></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span style='font-size:20.0pt'>Pictures of the actual opto-sensor setup:<o:p></o:p></span></p><p class=MsoPlainText><o:p> </o:p></p><p class=MsoPlainText><span style='mso-ligatures:none'><img border=0 width=703 height=945 style='width:7.3229in;height:9.8437in' id="Image_x0020_4" src="cid:image001.png@01DB5F83.CBE3F3B0"></span><o:p></o:p></p><p class=MsoPlainText><span style='mso-ligatures:none'><img border=0 width=676 height=543 style='width:7.0416in;height:5.6562in' id="Image_x0020_3" src="cid:image008.jpg@01DB5F85.EFFB8950"></span><o:p></o:p></p><p class=MsoPlainText><span style='mso-ligatures:none'><img border=0 width=675 height=524 style='width:7.0312in;height:5.4583in' id="Image_x0020_2" src="cid:image009.jpg@01DB5F85.EFFB8950"></span><o:p></o:p></p><p class=MsoPlainText><span style='mso-ligatures:none'><img border=0 width=676 height=612 style='width:7.0416in;height:6.375in' id="Image_x0020_1" src="cid:image010.jpg@01DB5F85.EFFB8950"></span><o:p></o:p></p></div></body></html>