I appolagize if my description wasn't clear, but it sounds like you
got the basic right idea.

> > So is this idea insane?
>
> For some thresholds of sanity.  How accurate does it need to be?  For how
> long after starting from a known position?

Accurate to within ~5 deg or better, for at least ~10 mins.

> > I'm aware of digital compass modules, and that is a possibility,
> > however those need to be level to operate,
>
> Why?  You should be able to measure the direction of external magnetic field
> lines.  At least this will have a fixed angular error which will not
> accumulate over time.  Whether the external magnetic field lines are all
> parallel over the operating range of your device is another question.

I meant to specify 2-axis compass modules (which we can afford), from
what I've read in the datasheets I understand that they must be level
and calibrated to be accurate, perhaps this is only true if you
actually care where North is?

> What year are you in?  What course is this for?  What is your major?

I'm in my 4th year, but have one year remaining after this one. I'm
working on a BS in Computer Engineering Tech, BS in Software
Engineering Tech, AE in Electronics Engineering Tech, and minor in
math. I think I've found that I enjoy the hardward side of things much
more than the high level software. This is for a 'Junior' Project
class, a year long 5 person team project class.

The entire project is actually a nerf targeting system. We're mounting
a distance sensor, wind sensor, and rotation/incline sensor system
(what I'm working on right now) so that the user can aim at the
target, push a button and the required trajectory will be calculated
and the user will then be guided to the correct rotation and
inclination to fire. The gun should be operated as normal (on the
shoulder) so we decided not to just use a tripod (which would have
made it a bit easier). So yes it's a pretty fun project :). This
project was inspired by the airsoft (think paintball) team on campus
hoping to make some sort of mortor system.

We've ordered a 2 axis compass module that has a nice I2C interface, I
think we're going to give up on using the accel for rotation unless
somebody here give me some good ideas. It would be a fun project for
later though. Maybe a stick w/ an accel at both ends that can be moved
around in more than just a sphere.

Thanks for your responce,

~Jake B

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