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David Kissick
08-25-2004, 10:02 AM
I was wondering if anyone has ever tried to use a digital compass IC on a stamp project. I'm just trying to get an idea of how to interface with one. Thanks for any advice.

David

Mike Cook
08-25-2004, 10:21 AM
David,

·I've used the Dimsmore Digital Sensor # 1490, this is the same sensor that Parallax uses on their Compass Appmod Stock# 29113. Here's a link to the documentation on the sensor:

http://www-2.cs.cmu.edu/afs/cs.cmu.edu/academic/class/16861-f02/www/files/imap_10_23/COMPASS/DINSMORE%20COMPASS%20SENSOR%20INFO.pdf

It's a simple Hall-effect that magnetically indicates the four Cardinal (N. E, S. W) directions, and, by overlapping the four Cardinal directions, shows the four intermediate (NE, NW, SE, SW) directions.

Mike

Jon Williams
08-25-2004, 12:40 PM
I've used the Devantech compass -- an I2C device with all members of the BS2 family.· It is nice in that you can read the direction right out a register and it's supposed to be good for 2 degrees of resolution.




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Jon Williams
Applications Engineer, Parallax
Dallas Office

Mike Cook
08-27-2004, 06:52 AM
Jon,

Is there a place in the US where you can purchase the Devantech compass? I would like to experiment with it.

Thanks,

Mike

Chris Savage
08-27-2004, 06:57 AM
Here's a place:

http://www.superdroidrobots.com/sensors_compass.htm

Hope this helps...· http://forums.parallax.com/images/smilies/smilewinkgrin.gif

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Chris Savage

Knight Designs
324 West Main Street
P.O. Box 97
Montour Falls, NY 14865
(607) 535-6777

Business Page:·· http://www.knightdesigns.com
Personal Page:··· http://www.lightlink.com/dream/chris
·

Mike Cook
08-27-2004, 07:08 AM
Cool!

gota get one, I've got a C-Band Dish that I would like to convert to AZ/EL, and would like some positive feedback from the control electronics.

Thanks,

Mike



P.S dang it Chris you Just cost me $56.85! Thanks for the Link!

Post Edited (Mike Cook) : 8/26/2004 11:20:07 PM GMT

Jon Williams
08-27-2004, 07:29 AM
You can also get the Devantech compass from Acroname (www.acroname.com).

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Jon Williams
Applications Engineer, Parallax
Dallas Office

steve_b
08-27-2004, 08:58 PM
I'm not sure if this will be accurate enough for you.

I work on weather radars and we get angle data down to the hundreths of a degree.· But we use syncrho's to tell us where we're at.

·

A synchro is basically a backwards operating motor....I know I didn't describe it very well there.

But, it's not connecting to turn the dish....the dish is spun by a separate motor.· We connect the synchro to the same gears so that the dish spins the synchro.· The synchro has 3 coils that offer up a different voltage/phase relationship depending on the shafts location.· You can buy synchro resolvers that will figure out the sine/cosine angles and give you an output.· These are pretty decent.

here's one from Analog Devices ( http://www.analog.com/Analog_Root/productPage/productHome/0,2121,generic%253DSDC1741%2526level4%253D367%2526 Language%253DEnglish%2526level1%253D214%2526level2 %253D235%2526level3%253D361,00.html (http://www.analog.com/Analog_Root/productPage/productHome/0,2121,generic%253DSDC1741%2526level4%253D367%2526 Language%253DEnglish%2526level1%253D214%2526level2 %253D235%2526level3%253D361,00.html)·)

Ya, they're long!!

Anyhow, be sure to match your synchro-to-digital IC with the type of synchro you have. (some synchro's have different reference voltages and operate at different frequencies).

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·

Steve
http://members.rogers.com/steve.brady (http://members.rogers.com/steve.brady)
http://www.geocities.com/paulsopenstage (http://www.geocities.com/paulsopenstage)

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

Chris Savage
08-27-2004, 10:21 PM
Mike Cook said...
P.S dang it Chris you Just cost me $56.85! Thanks for the Link!
Hey!· Glad to be of help!· Just returning the favor from my favorite salesman at Parallax, whom, almost everytime I talk to him, I spend all my money!· Hehe· Gotta have the toys...

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Chris Savage

Knight Designs
324 West Main Street
P.O. Box 97
Montour Falls, NY 14865
(607) 535-6777

Business Page:·· http://www.knightdesigns.com
Personal Page:··· http://www.lightlink.com/dream/chris
·