#compass module

So in continuing with our mini series, let's get the Compass Module working wirelessly with the XBee as well!  Here's the information to get it working period: 

http://tymkrs.tumblr.com/post/22237323716/parallax-compass-module-3-axis-hmc5883l-29133

http://tymkrs.tumblr.com/post/22258810035/parallax-compass-module-3-axis-hmc5883l-29133-part

Base Node:

Code: http://pastebin.com/T80ZFmsd

Hardware:

Remote Node:

Code: http://pastebin.com/aGSFG1Ft

Object Code Needed: SL32_IntEngine_2.spin if you can't find it: http://pastebin.com/atC59gzV

Hardware:

When you run it, you should see what you would if the Compass Module were not wireless, and indeed, it is so!

So I'm still working on the Compass Module and wanted to post some pictures of the data I received after plotting each point according to this picture:

I rotated the module board until the serial terminal read North or N10E or N20E all the way around and recorded the X, Y, Z, and azimuth readings.

Then put it into a graph form, because...you know...graphs are awesome:

And to get that information, normally you'd read the object that the program referenced to see how to get the information from the obj's mini files or whatever.  But that is all available in the Demo program from the Parallax site: http://www.parallax.com/StoreSearchResults/tabid/768/List/0/SortField/4/ProductID/779/Default.aspx?txtSearch=compass+module

So the demo code itself "only" gives the X, Y, Z, and Heading (as in North, N10W, etc).  I wanted to add azimuth and I noticed the code had segments for it:

I noticed that Pub Main had "Heading Term" in its code.  And later on there was a Pub Heading Term.  So I decided since I could see Pub AzimuthTerm, that I'd add AzimuthTerm into PubMain and see if I get Azimuth information...andd....

VOILA!

Cool.  AND the graphs are pretty :)

So in our ever continuing quest to play with different peripherals and sensors - we have the compass module!  Now according to the site:

"The Compass Module 3-Axis HMC5883L is designed for low-field magnetic sensing with a digital interface. This compact sensor fits into small projects such as UAVs and robot navigation systems.

The sensor converts any magnetic field to a differential voltage output on 3 axes. This voltage shift is the raw digital output value, which can then be used to calculate headings or sense magnetic fields coming from different directions."

We'll go again to the Kickstart Site so I'm not reinventing the wheel and it would seem that all I had to do for wiring was take the gyroscope module OFF, and plug this in almost EXACTLY the same place.  How convenient is that?!

Code and Demo:

I'm still finagling with it but here are a couple of options for experimentation:

https://sites.google.com/site/parallaxinretailstores/Compass-Propeller.zip?attredirects=0

With that kickstart code the -101, -158, -520 stands for the voltage outputs on the three axis.  ...I still don't really know what that means...

http://www.parallax.com/portals/0/downloads/docs/prod/sens/29133-CompassSpinDemo.zip

Cool!  So when you rotate this one around, you see the X/Y/Z changing a bit (though its meaning is still beyond me), but you get to see the Heading in Degrees change from North to different degrees of NW or NE, to South and so on!

Nub Mistake:

So I didn't look carefully (though I thought I had) at the wiring.  Remember to know which pins your SCL and SDA are connected to.  When you flipflop them, this is what you get.  It stays stuck at NORTH and no matter what you do to the module, the X/Y/Z are all at -1.  I'm still not sure what the square symbols are....but I'm sure I'll be able to find them.

Extra notes:

You will need to put "SL32_INTEngine_2.spin" into your PropTool Library.  Based on the innards, it looks like it takes care of any geometric math that may be required in the main program.  And with the Compass Spin Demo, you need to make sure that the Parallax Serial Terminal is running on the same baud rate, otherwise you won't see anything happening (as I found out!).

I will keep working on it!