Guest 01bc Posted July 21, 2004 Report Share Posted July 21, 2004 anyone have a source for a high resolution (100+ pulses per rev) non-detented encoder with a metal shaft? all i can find are ones in the hundreds of pounds which is not great..i've tried all the links from the ucapps where to order page and not found anything yet..j Quote Link to comment Share on other sites More sharing options...
smashtv Posted July 21, 2004 Report Share Posted July 21, 2004 Hi J!Motion control? Tracking a turntable? Just curious...... ;)You might consider building your own optical encoder out of old mouse parts. There are many articles about this here and out on the web. A modified potentiometer, a custom interruptor disc and some optos are all you need. This technique is very popular with robot builders.Have Fun!SmashTV Quote Link to comment Share on other sites More sharing options...
moebius Posted July 21, 2004 Report Share Posted July 21, 2004 Or HD stepper motor?!http://www.hut.fi/~jwagner/electr/rotary-enc/http://members.iinet.net.au/~richardh/Rotenc.htmBye, Moebius Quote Link to comment Share on other sites More sharing options...
Screaming_Rabbit Posted August 16, 2004 Report Share Posted August 16, 2004 I'm getting more and more interrested in this stepper motor thing. "Fx3_hdrive" opened a thread on that a while ago.Does anybody experienced the feel of a Fairlight MFX Jog-wheel yet? It's smooth, is easy to turn but still got some resistance or mass. I could imagine that a stepper motor gives a nice feel with it's perfect fit with bearings. If the output voltage at low speed is a problem, you could change transmission when you drive it over a tooth belt (is that the right expression? In gerrman: Zahnriemen) http://image01.conrad.com/m/2000_2999/2200/2260/2260/226050_BB_00_FB.EPS.jpgGreets, Roger Quote Link to comment Share on other sites More sharing options...
argtrak Posted August 24, 2004 Report Share Posted August 24, 2004 Hmm, low voltage at low speed, doesn't that raises a potential issue of high voltage at high speed? Â I'm not sure what kind of maximum voltage could come out of a stepper motor at high speed, but it might be more than the 5 volt the DIN are supposed to receive... or maybe even outside the maximum the DIN can handle? Going to fast with a belt trainy might generate pulses too quickly for mios to handle correctly if the stepper has enough steps per turn. And (excluding HD steppers from what I read)at high enough rotation speed the stepping noise created may become an issue if you need a noiseless setup. Â All the stepper motors (not-HD)I have move with a feel similar to detented encoders(just a little softer), and if I turn them fast do they get somewhat noisy. It's true that HD feel different but then I'm not sure about how many steps per turn, they've got.. Â For my part, I'll be going with optical. Mouse optical encoders on the other hand should provide a very stable voltage, low or high speed. Â About the tight feel, that all depends on your construction. Â As mentionned earlier, modifying a pot for continuous rotation should give you a nice enough feel. Â All that's left is the actual construction of the device which shouldn't be too complicated if you use your imagination... Â ;)My 2 cents...Pascal Quote Link to comment Share on other sites More sharing options...
Screaming_Rabbit Posted August 24, 2004 Report Share Posted August 24, 2004 Hi PascalI'm not an electronic crack but what you write, sounds logical to be and could me a problem.Optical (I already took two mices out of the technical garbage at our studios  ;)) I like because there is no friction (aging). You're right, that the feel could be achieved with bearings on the wheel shaft and a heavy enough material for the wheel. Fairlight uses a piece of piano damping fabric (propably the wrong expression) which is pressed on to the shaft by a spring loaded screw.Greets, Roger Quote Link to comment Share on other sites More sharing options...
gillesdeshays Posted August 26, 2004 Report Share Posted August 26, 2004 there is the BOURNS ACE128 ....here is the datasheetcheck this : http://ourworld.compuserve.com/homepages/steve_lawther/bourns.htmhope this help ...gilles Quote Link to comment Share on other sites More sharing options...
moebius Posted August 26, 2004 Report Share Posted August 26, 2004 Blaa blablaa blaa..Well,What the f**k are those comparators doing in the schematic?(Second link, with pic missing can be reach from: http://web.archive.org/web/20030423083039/http://members.iinet.net.au/~richardh/Rotenc.htm)Bye, Moebius Quote Link to comment Share on other sites More sharing options...
smashtv Posted August 26, 2004 Report Share Posted August 26, 2004 Well,What the f**k are those comparators doing in the schematic?(Second link, with pic missing can be reach from: http://web.archive.org/web/20030423083039/http://members.iinet.net.au/~richardh/Rotenc.htm)Bye, MoebiusJust a guess, but it looks like the comparators are there to allow it to read at very low rpm/single step, as the motor probably would kick out a weak and strange looking wave (not square) without a buffer at very low speeds.It's also worth noting that this design at anything but very low speeds would probably cause huge amounts of noise on the power supply rails.Best!Smash Quote Link to comment Share on other sites More sharing options...
moebius Posted August 27, 2004 Report Share Posted August 27, 2004 SmashTV..Sorry, I was trying to be sarcastic, as argtrak, speculated 'bout things, which should be clear (and thought as solved) after reading links I gave.Noise.. Ground, decouple, decouple, decouple...And yes, comparators clear signal from steppers (even as low as 5mV) to digital pulses.Bye, Moebius(And yeaaahh..HD stepper is so smoooth.. ah...) Quote Link to comment Share on other sites More sharing options...
argtrak Posted August 27, 2004 Report Share Posted August 27, 2004 Thanks for the info SmashTV...Sorry, I was trying to be sarcastic, as argtrak, speculated 'bout things, which should be clear (and thought as solved) after reading links I gave.I guess I didn't read the links well enough, plus I never worked with comparators. My mistake. :-/So... Moebius, (or anyone...) how many steps does a HD stepper usually have per turn? I'm curious. :)Pascal Quote Link to comment Share on other sites More sharing options...
smashtv Posted August 27, 2004 Report Share Posted August 27, 2004 SmashTV..Sorry, I was trying to be sarcastic, as argtrak, speculated 'bout things, which should be clear (and thought as solved) after reading links I gave.Noise.. Ground, decouple, decouple, decouple...And yes, comparators clear signal from steppers (even as low as 5mV) to digital pulses.Bye, Moebius(And yeaaahh..HD stepper is so smoooth.. ah...)Whoop my sarcasm radar must be way off these days.... :) Quote Link to comment Share on other sites More sharing options...
Fx3_hdrive Posted December 16, 2005 Report Share Posted December 16, 2005 http://www.midibox.org/forum/index.php?topic=2926.0i was wondering when the issue will pop up :Pyes, at low speeds the motor produces little voltage, but its big enough for a comparator, if u want even lower speeds u can include another opamp or something to increase the gain at low voltage, and atenute it if its too big."the circuit responded as low as 1/3 r.p.m."again i must underline that this is a very low speed.ps. if u dont use the HD steppers and use the normal ones where u can feel dents, (its not mechanical dents, its magnetic) then u can use that as 1 value increment.i have dont a little testing (as u can read on my earlier thread) with an oscilloscope and an led.(one day all i did was sit around turning the HD stepper ;D) Quote Link to comment Share on other sites More sharing options...
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