Subject:
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Re: Rotation Sensors - slightly dissapointed...
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 25 Feb 2000 18:28:43 GMT
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Viewed:
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945 times
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In lugnet.robotics, Michael Gasperi writes:
> In lugnet.robotics, Iain Hendry writes:
> > The program ran successfully for about 20 seconds before I noticed motor 1
> > had shifted out of phase by 22.5 degrees - it had slipped/skipped a count.
>
> Because the LEGO Rotation sensor is a powered type, it might be slightly
> sensitive to battery voltage.
If you check the legOS group you can see my posts with some extensive analysis
of the sensor values for the rotation sensor. There is a patch to make legOS
less sensitive to voltage fluctuations and one to debounce the input (which is
what probably causes missed counts on the standard firmware as well). I was
working on very similar designs to those being discussed in this thread, and
with my changes (using legOS, of course) you get the expected behavior, with no
missed (or extra) counts.
I doubt you can get very high precision from the stock firmware.
--Ben
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Message has 2 Replies:
 | | RE: Rotation Sensors - slightly dissapointed...
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| (...) Ben, I have to go back over the changes, but does legOS sample at the same rate as the standard firmware? The standard rate is about 333hz, so debouncing would likely reduce the effective rate to 166hz, which limits the max rate at which the (...) (25 years ago, 25-Feb-00, to lugnet.robotics)
| | | Re: Rotation Sensors - slightly dissapointed...
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| I've used old mouse rotation sensors in non-lego projects with some success. They employ a laser counter. The device can be easily connected to a basic stamp. If the counter disk is sealed against contaminantion it works well. Robb, ----- Original (...) (25 years ago, 28-Feb-00, to lugnet.robotics)
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Message is in Reply To:
| | Re: Rotation Sensors - slightly dissapointed...
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| (...) Because the LEGO Rotation sensor is a powered type, it might be slightly sensitive to battery voltage. I wonder if you notice the skipping is worse with older batteries. Also, the problem might be aggravated by long wires. Does the skipping (...) (25 years ago, 25-Feb-00, to lugnet.robotics)
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