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ALIBE
10-26-2006, 04:38 AM
I could'nt stop myself but to jump up and abt that my new parts have arrived today. 1) GPS and 2) Compass. Once I get my comm module moved over to a dedicated Cog tonight, I should start looking into these two. One at a time :)

I still need to see how I'm going to assemble my parts on ALIBE.



I must say, on a side note that Chris Savage in Tech support was awesome in help answering various range of questions and recommendations. I must say yet again, Parallax Support Rocks!!
http://forums.parallax.com/forums/posticons/icon13.gif

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"any small object, accidentally dropped, goes and hides behind a larger object."


ALIBE - Artificial LIfe BEing. In search of building autonoumous land robot
http://ALIBE.crosscity.com/ (http://ALIBE.crosscity.com/)

Bergamot
10-26-2006, 07:35 PM
Don't most GPS modules have compasses onboard?

ALIBE
10-26-2006, 08:48 PM
most of the consumer ones do. However majority of those that are microcontroller or other "master" programmable that I have seen do not. Parallax's GPS Module does not.

It is also worth mentioning that not all applications need the combination. For example, let's suppose you're only interested in capturing the NMEA data (l/l/a) for stamping Pictures' EXIF data, one would normally not care for compass info and therefore will not need compass features there.

I believe to keep the cost-to-make and price-to-buy under control, they are usually kept separate.

hope that helps answer your question

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"any small object, accidentally dropped, goes and hides behind a larger object."


ALIBE - Artificial LIfe BEing. In search of building autonoumous land robot
http://ALIBE.crosscity.com/ (http://ALIBE.crosscity.com/)

Charlie Johnson
10-26-2006, 09:14 PM
Bergamot said...
Don't most GPS modules have compasses onboard?
Most GPS units compute the heading based on movement, if the GPS is not moving, the heading info will not be reliable. There are some GPS units that do have a seperate built in compass and can provide heading info even when stationary.

Charlie

Chris Savage
10-31-2006, 10:35 AM
Charlie,

In fact, due to drift/error it’s possible for a compass module to report inaccurate heading…Picture the GPS triangulating your coordinates at point X,Y then on the next scan X,Y-3…Now it appears that you’re moving backward and you haven’t moved at all.

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Chris Savage
Parallax Tech Support

James Long
10-31-2006, 12:19 PM
Also (for what it's worth) you may be pointing in a direction...that you are not necessarily heading in.

Drift in an aircraft, for instance.



James L

Phil Pilgrim (PhiPi)
10-31-2006, 02:58 PM
There are three related navigational terms that come into play here:

Bearing: the direction from you to another point, such as a waypoint or incoming torpedo (measured with a transit or sighting compass).
Heading: the direction you're moving (measured with a GPS unit).
Azimuth: the direction you're pointed (measured with a compass or gyroscope).

I had to look them up. I can never seem to remember which is which. http://forums.parallax.com/images/smilies/smile.gif

-Phil

ciw1973
10-31-2006, 05:01 PM
I ordered one of FTDI's DLP-PROP modules (and a PIC module) for a friend, who now doesn't want them. Despite sending an email within 20 minutes of placing the order, two days later they still shipped the products.

It kind of annoyed me a bit, but I was considering getting one of these anyway, although I did want to have a look at one in the flesh first. Fate steps in and I end up with new toys. Bugger. The wife'll not believe it was a mix-up though, she'll just see more "nerd toys" around the place and another transaction on the bank statement.

parsko
10-31-2006, 06:02 PM
ciw1973 said...
...The wife'll not believe it was a mix-up though, she'll just see more "nerd toys" around the place...


But it's perfectly acceptable to "mix-up" buying $100 worth of make-up (which is a consumable, not an investment)!!!!!

Regardless of how you explain it, your Azimuth will not coincide with her view of your Bearing, and thus you will be Heading toward a fight (unless she's a nerd too, in which case I envy you!).

Sorry, I couldn't resist the cheesy joke...

-Parsko

ciw1973
10-31-2006, 07:01 PM
Nah, to be honest she's actually fine about such things, and I have to admint that there's kit at home which I ordered six months ago that still hasn't been taken out of the packaging.

She's not particularly nerdy, but does take an interest in what I'm tinkering with from time to time, but that's mainly the more visual stuff. She's a primary school teacher, and I'm probably the biggest kid she has to deal with each day.

MacGeek117
11-01-2006, 12:22 AM
If only we all had someone like that in our lives!
RoboGeek

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