Subject:
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Re: Struggling with encoder wheel
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 12 Apr 2001 05:03:29 GMT
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Viewed:
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996 times
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In article <GBnvns.3vw@lugnet.com>, Xanthra47 <jmantor@nycap.rr.com> wrote:
> As for speeding up the system you've got, I'm not sure I can help
> there... It seems that you've done a very good job optimizing it for
> compact storage. I was trying to fathom a hash function to help
> here, but I haven't come up with one that wouldn't take much more
> space to store the table. I'm intrigued though : )
If I had room for a 64 element array, I'd just use that and make a
lookup table. Unfortunately I don't, and I can't figure out a way to
pack things in and still look them up with any speed. I also can't
find any way to mathematically convert the group of wedges to a
position either, and since they're laid out kinda wildly, there
probably isn't a way.
I also still have problems getting semi-accurate reads. As the wheel
turns and the sensor sits between two different colors, it tends to
see it as a different gray and misreads.
--
Chris Osborn Full System, Inc.
fozztexx@fullsystem.com 2160 Jefferson St., #240
http://www.fullsystem.com/ Napa, CA 94559
Webhosting that *works* - 99.99% uptime - First 3 months free
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Message has 3 Replies:
 | | Re: Struggling with encoder wheel
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| (...) Can't you just use a large switch() statement inside a function to simulate a 64 element array? If none of the values in the array ever change: int array ( int x ) { switch ( x ) { case 0 : return element_0 ; case 1 : return element_1 ; case 2 (...) (24 years ago, 12-Apr-01, to lugnet.robotics)
| | | Re: Struggling with encoder wheel
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| (...) I was wondering how you were handling the edge conditions. Have you tried making a wheel which is a continuous gradiant from black to white over the 360 degrees of rotation? Lookup wouldn't be required as there would be a direct relationship (...) (24 years ago, 12-Apr-01, to lugnet.robotics)
| | | Re: Struggling with encoder wheel
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| (...) You could make a big wheel made of lego plates, and put smooth ones on top for 'colors'. Then you could use a touch sensor, and use the difference between the low spots and the high spots as 1 location. Do you really need to know the direction (...) (24 years ago, 12-Apr-01, to lugnet.robotics)
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Message is in Reply To:
| | Re: Struggling with encoder wheel
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| Pretty neat Chris. You've very nearly recreated a special kind of optical encoder that was developed by my former employers called a virtual absolute encoder. It didn't use diferent colors but it used a "time-window" to read the last few states off (...) (24 years ago, 12-Apr-01, to lugnet.robotics)
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