Subject:
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Re: Voltage generator/Anemometer
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 22 Jan 1999 03:39:42 GMT
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Original-From:
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Zachary A. Bourk <zbourk@san.rr./StopSpammers/com>
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Viewed:
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1223 times
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Jim:
Would not the readings gleaned from a motor only be valid when the motor
is already turning and has overcome "stick-tion" and the back-emf that
would be created when it tried to move the motor? Also, using something
as crude as coat hanger and "yoghurt pots" as proposed would also be
none too good considering the fact that the rotation of the arms would
be severely impeded when the pots were in certain configurations, such
as on a perfectly vertical axis with each other. If created it could use
blades made from Aluminum soda cans or the like(weight being a source of
error) and its input could be taken by using either a rotation sensor
(if one is available to you) or a light sensor, with which you could use
a Tango (R) can, (I was in England over the summer 1998 and I consumed a
few Tango (R) beverages--I think they are dispensed there), one of the
generally black ones, with a light source on the opposing side of the
prop blades to create something like the "photogates" modelled on those
found in a high school or university Physics class. (If you have to
write up expenses then you can also write off a few six packs of Tango
(R) beverage on the "scientific supplies" category, which you "had to
empty to prepare them for the project".) This would give very accurate
readings and with the flat black finish, (I think Tango (R) uses flat
black), and a large enough number of blades, you could have a very
precise way to measure the rotation.
-Zach
Of what I speak:
_______________ _____________________
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/ \ /
| / \
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Light source Space through RCX sensor
which the blades
may pass
+++++++++++++++++++++++++++++
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Axis on which the blades can rotate (created on user disgression and
need for strength). The axis could also be used, if so robust, to secure
the light source and RCX sensor so as to have them close together.
-Zach
jeff wrote:
>
> Jim,
>
> Thanks for the info. on your experience. I was thinking of using the
> car, and was a bit worried about the accuracy problem. Your suggestions
> are great though and have me believing I'll try something like what you
> did. I was thinking about making a windmill that would connect to a Lego
> motor, and reading the resulting current with the RCX. Have to see about
> that still - yet I'd love to have a Lego wind sensor.
>
> Thanks,
> Jeff D. Payne
> UtahLINK Network Operations
>
> On Wed, 20 Jan 1999, Jim Thomson wrote:
> >
> > I made one some time ago for a project using a bike speedo (one of the
> > digital ones which comes with a reed switch to go on the forks and a little
> > magnet which clips on a spoke). This measured the revolution speed of a
> > windmill type thing made from coat hangers and yoghurt pots.
> >
> > To calibrate it we drove a car along a straight and empty piece of road with
> > the anemometer on the roof. We did it in both directions and averaged the
> > result (to try to cancel out any effect the wind would have). We just used
> > the car speedo for the speed, though they are notoriously inaccurate. A
> > measured length of road can of course be used to calibrate the car
> > speedo.....if you have the time.
> >
> > For best results it would be wise to mount the anemometer well above the car
> > to reduce the effects of the air flow being disturbed by the car.
> >
> > I hope this still counts as being Lego related.
> >
> > Jim
> >
> > ---------------------------------------------------------------
> > Jim Thomson, Jesus College, Cambridge. CB5 8BL
> > Web Page www2.eng.cam.ac.uk/~95jmt2/index.html
>
>
> --
> Did you check the web site first?: http://www.crynwr.com/lego-robotics
--
--------------------
Zachary Bourk
UCSD, EE
http:\\www.geocities.com\ResearchTriangle\System\4968
--------------------
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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Message is in Reply To:
 | | Re: Voltage generator/Anemometer
|
| Jim, Thanks for the info. on your experience. I was thinking of using the car, and was a bit worried about the accuracy problem. Your suggestions are great though and have me believing I'll try something like what you did. I was thinking about (...) (26 years ago, 20-Jan-99, to lugnet.robotics)
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