This is probably a dumb question, but I am curious as to how this module works. More specifically, does the output identify its orientation or change in orientation?
I am looking to potentially use this in a project where it would be very helpful if this could give an accurate measurement of the units current orientation even based upon an initial set zero orientation.
A gyro shows the rate of rotation. For detecting the orientation of a generally stationary object you want to use an accelerometer -- when at rest (not being shaken, moved, etc.) it will detect the direction that gravity is pulling it.
Take a look at page 12 of this datasheet for a more pictoral explanation of how an accelerometer reads gravity.
To head off a potential question, you might ask why a gyro would not work given the ability to read its initial status and watch all the changes in rotation that it makes. The main problem is that this is not accurate over long periods of time but also that gyroscopes are subject to "drift" and will report that they are always slowly changing their rotation.
Thanks for the information. I can see that this wouldn't work for what I am thinking. I was looking for something more like a compass in functionality as the unit is stationary.
Know of any kind of digital compass sensor?
That would be a "magnetometer". Here's one: Triple Axis Magnetometer Breakout - MAG3110 - SEN-10619 - SparkFun Electronics
I have no experience with magnetometers so perhaps someone else will chime in with the potential issues in using one.
Didn't think to actually look for a compass module but I found this which seems like it would work perfectly although it is out of stock.
I haven't ever worked with I2C but it describes it as being simple in the details.
According to the magnetometer you linked, it needs a accelerometer as well to act as a tilt compensated compass. Not too sure on whether it functions as a compass on its own with no tilt compensation.
Edit:
I also found this: http://www.sparkfun.com/products/9302 which is so cheap I'm just going to get one anyways and play with it. If it can get an xy plane orientation of some sort, I'd be all set.
HMC6352 is only a 2-axis compass.
With respect to tilt compensation, I understand that this is used to negate any effect on the compass' readout when it is flipped, etc.
Hopefully someone else will chime in on this. I'm pretty confused myself.