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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Fri, 13 Apr 2001 07:20:20 GMT
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Viewed:
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1224 times
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> The light sensor just doesn't have that kind of resolution. I'd never
> get a very accurate position by doing that, I wanted a finer
> positioning system than I can get from using a rotation sensor.
I did an experiment printing out many different gradients and I now
understand part of your problem. It was hard to get any change in the
reading (~40 - 50). So next I then cut a wedge shaped slit in a piece of
white paper. Aiming the sensor at this target gave me a little better
range, but still not great. Next I aimed the sensor directly at a 60 watt
bulb. By covering the lens with a black cloth I was able to get readings
from 45 to 100. In raw mode that was 700 to 500. I'm sure I could do even
better if I was willing to pull out the soldering iron and remove the red LED.
As far as the rotation sensor, you could always use gearing to increase the
resolution. Place it on the shaft of a worm gear driving a 42 tooth gear
and you get 1 count = 1/2deg (approx). It's not as cool as an optical
encoder, but it is robust.
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Message has 1 Reply:
 | | Re: Struggling with encoder wheel
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| (...) That was the first version of the webcam mount. After rotating back and forth a few times you can't tell where the camera is anymore. There also aren't any 42 tooth gears BTW, just a 40. Last night I used the datalog to record what the light (...) (24 years ago, 13-Apr-01, to lugnet.robotics)
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Message is in Reply To:
| | Re: Struggling with encoder wheel
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| (...) The light sensor just doesn't have that kind of resolution. I'd never get a very accurate position by doing that, I wanted a finer positioning system than I can get from using a rotation sensor. I'm trying to build something that's got (...) (24 years ago, 12-Apr-01, to lugnet.robotics)
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