Subject:
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Re: Compass update
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 10 Nov 2000 16:05:29 GMT
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Original-From:
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Trent McConaghy <trentm@analogsynthesis.#stopspammers#com>
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Viewed:
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373 times
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Hello,
Here's a challenge for those of you with Lego cameras and want compass navigation:
Point the camera at a compass and process the visual information into directional
input. It's a bit more crude, but you can get away with almost any old compass;
it doesn't need to be electronic!
(I won't be building this because I don't have the camera system. I'm not even
sure if I have a compass!)
Cheers,
Trent McConaghy
John Barnes wrote:
> I have been working away at the compass problem for a while.
> (I suppose it's only a problem if the kinds of things you're using
> an RCX for involve knowing which way you're pointing ...)
>
> I have built a number of compasses based on both Dinsmore and
> Vector modules.
>
> I was recently in touch with the folks at Precision Navigation who
> have been extremely helpful (and who make the Vector solid state
> compass module) and they had two interesting pieces of information.
>
> 1. The current product will run in uncalibrated mode, despite the fact
> that the documentation states that calibration is required. The problem
> with calibration is that you have to "swing" the compass in "Cal" mode
> whereupon it will retain calibration values internally in RAM. Sadly, the
> cal data is lost when power is removed. In automobile type applications
> where the few hundered micro-amps required to leave it powered don't
> matter, this is not a problem. But as Lego sensor, it does, not to mention
> having to have "cal" and "operate" buttons etc to perform the function.
>
> I have reworked my Vector based compasses to run in uncalibrated mode
> and they seem perfectly fine, good to within about 5% as far as I can tell.
>
> The only downside is the size. You have to build a little board with a PIC
> or something to take the serial data from the Vector and convert it to a
> current to feed to the RCX and of course the power/signal demux function.
> When all is said and done, you end up with a 6 stud on a side cube. I
> personally find this large in comparison with other Mindstorms scale
> components. Which bring me to ..
>
> 2. Precision Navigation are coming out with a smaller device at the beginning
> of next year. I hope I am near the top of their list for a couple of devices to
> try. Their promise of a 1" x 1" module is perfect for fitting into a 4 x 4 stud
> enclosure which is much more in keeping with the scale of things.
>
> I will post more as and when I have more news.
>
> JB
>
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Message has 2 Replies:
 | | Re: Compass update
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| (...) Hi, I'm planning of doing this with a light sensor. I'm going to attach a disk with information (stripes of different colors) to the compass, and the light sensor will read the information. I´ll post a message here when I have it ready. Best (...) (24 years ago, 11-Nov-00, to lugnet.robotics)
| | | Re: Compass update
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| (...) navigation: (...) directional (...) compass; (...) even (...) Nice Idea but what is with the f****** cable ?? Rainer (24 years ago, 11-Nov-00, to lugnet.robotics)
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Message is in Reply To:
| | Compass update
|
| I have been working away at the compass problem for a while. (I suppose it's only a problem if the kinds of things you're using an RCX for involve knowing which way you're pointing ...) I have built a number of compasses based on both Dinsmore and (...) (24 years ago, 10-Nov-00, to lugnet.robotics)
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