Multi turn absolute optical encoders
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Categories All Categories What kind of accuracy can I reasonably expect with a 13 bit optical encoder robotics mounted on a rotating gear shaft? I've been playing with a simple voltage divider and notice fluctuations of digits with an 8bit dac. Also, is there a source of inexpensive high resolution optical encoders out there absolute or incremental?
Thanks for any help! Comments 20 Comments sorted by Date Added Votes. You don't want to hear "you get what you pay for", but that's exactly what's going on here. Temperature may even cause variations in some situations.
Adding a wheatstone bridge is unlikely to add any stability or accuracy. Optical encoders are much more demanding, both mechanically and electrically. If it isn't perfectly centered and perpendicular to the shaft which must be rock solid and trueyou will get erroneous readings. All that electromechanical accuracy come at a price. People can and so make their own encoders, it is rewarding work 13 bit optical encoder robotics teaches you the appreciation for the 13 bit optical encoder robotics required.
And they can make it pretty, and so everybody can like it when others make it after you. Chris Savage Parallax Engineering Posts: POTs are analog and subject to non-linearity and noise. If your hardware can handle the encoder I would recommend that.
Isn't there something like that but a lot cheaper? I'm kind of shocked the are 13 bit optical encoder robotics so high for something that seems so easy to manufacture on a mass scale. I would imagine you could easily make that sort of thing on a MEMs fabrication factory and pump them out at fractions of a cent each. Building my own seems like reinventing the wheel.
Certainly I cannot reproduce the accuracy of the encoder disc they can make in a clean room with a robot. The US Digital S5 seems ideal for my needs. I would just mount a little gear sprocket on it and attach it to my motor to get a very accurate reading. That said, both the S5 and motors with built in encoders are expensive. Is there no hobby supply of inexpensive encoders and motors with encoders? Phil Pilgrim PhiPi Posts: There are also magnetic encoders, such as this U.
Or, you could try rolling your own with this Melexis rotary position sensorwhich DigiKey carries. Depending on how fast your motor rotates you can use gears to make a 24 PPR go to ppr for example a rotating shaft at 10rpm would rotate another shaft at rpm and 13 bit optical encoder robotics would use the encoder on the rpm shaft.
Re-arrange what's inside the box then Think outside the BOX! I certainly wouldn't recommend an encoder with mechanical switch closures e. You really need a non-contact encoder for motor apps. Hmm that magnetic shaft encoder looks pretty sweet from US Digital since it'd be easier to interface than.
Any idea if magnetic interference is an issue? PWM absolute output is way better than the S4 quadrature output since you'd probably need a dedicate chip with interrupt and counter to not miss a pulse http: Doesn't anyone make products like US Digital but cheaper? Still not super cheap but I think I found a good solution out of the digikey catalog: These snap onto any shaft up to.
Also rolling your own is not that hard and then you can customize. Digital's would have fit my motors I would have used them on that project, I think.
When the going gets weird, the weird turn pro. I have made 3 sets and they all work great. I have virus checked and been using for a month or so. Might want to give it a look. I have to say that Pots aren't that bad. As erco says "you get what you pay for" and the cheapest solutions are pots. It all depends on your needs. Pots are really simple to use and automatically deliver an absolute position even for multiple revolutions. Precision pots are available and affordable even on 13 bit optical encoder robotics Of course, the amount of accuracy required in any application is a major consideration.
13 bit optical encoder robotics servos with cheap analog pots work well for a lot of applications. This original post mentioned optical encoders with bit accuracy, that's likely overkill for many apps. Sign In or Register to comment.
