# Some real basic accelerometer/IR questions

Posted by Kovacs
 Kovacs Some real basic accelerometer/IR questions November 23, 2009 04:31PM Registered: 14 years agoPosts: 11
Hi,

I'm quite inexperienced when it comes to programming, but I got it into my head to use the wiimote for my (psychology) thesis so I'm struggling through the subject matter.

I'm using LabVIEW to collect data from the wiimote using the interface provided by this site:

[decibel.ni.com]

So now I have accelerometer and IR data, but I'm not quite sure what I got precisely. Am I correct in assuming that:

-The accelerometers measure the proper acceleration they experience relative to freefall.
Acceleration is quantified in the SI unit m/s2 or popularly in terms of g-force (g).
The accelerometers measure linear accelerations along three fixed axes; they are unable to distinguish between linear motions and rotations, and so they are capable of measuring only pitch and roll angles.

-Is the picture below correct, because I've seen the same picture with all the "+ "and "-" mirrored?

-And then there is the IR data, I get raw and .. non-raw data as you can see here,

I'm not exactly sure what the raw and non-raw data is telling me here. Is it giving me the X, Y position of the IR LED.. or something else perhaps?

Thanks for your time, any help would be highly appreciated.
 Kovacs Re: Some real basic accelerometer/IR questions December 03, 2009 07:48PM Registered: 14 years agoPosts: 11
I did some more digging and I'm pretty confident about the following information, but I'd appreciate it if someone truly knowledgeable could confirm it.

-IR
The raw X and Y values are the IR Led (center) position on the camera's image plane?
The non-raw or normalized data I get with LabVIEW is just easier to work with I gather.

-Accelerometer
The accelerometers measure linear accelerations along three fixed axes; they are unable to distinguish between linear motions and rotations, and so they are capable of measuring only pitch and roll angles.

By the by, I still don't know which picture is right btw, the one above or this one:

 henke37 Re: Some real basic accelerometer/IR questions December 04, 2009 12:28PM Registered: 15 years agoPosts: 265
If you ask me, Y is up, X is to the right and Z is forward. Anything else is stupid.
 iSubaru Re: Some real basic accelerometer/IR questions December 05, 2009 10:23PM Registered: 14 years agoPosts: 55
That reminds me program wiigui if I recall correctly, it worked similar way, to debug what Wiimote "is doing" :P
 Kovacs Re: Some real basic accelerometer/IR questions December 06, 2009 03:27PM Registered: 14 years agoPosts: 11
Quote
iSubaru
That reminds me program wiigui if I recall correctly, it worked similar way, to debug what Wiimote "is doing" :P

You know, that actually sounds quite useful to me.
But is it a Linux program by any chance, 'cause that's the only hit I got really when searching for it?

Linux CWiid
CWiid is a collection of Linux tools written in C for interfacing to the Nintendo Wiimote. It contains a library (libcwiid), an event mouse joystick driver with plugin architecture (wminput), a GUI control panel and test application (wiigui) and a test/demo application (wiidemo).

 iSubaru Re: Some real basic accelerometer/IR questions December 06, 2009 09:33PM Registered: 14 years agoPosts: 55
Yup it's Linux program, You need Windows one?
I can try compiling it for Windows if I will find source but it may be difficult...

EDIT #1
In other hand I think there was Windows program which worked that way but maybe was called diffrently

Edited 1 time(s). Last edit at 12/06/2009 09:33PM by iSubaru.
 Kovacs Re: Some real basic accelerometer/IR questions December 07, 2009 05:05PM Registered: 14 years agoPosts: 11
I'm pretty sure it's called something else 'cause I don't get any hits when looking for it.
If the name pops in your head sometime I'd be much obliged if you mentioned it here again.

Cheers
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