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-   -   Question: Accelerometer accuracy (https://talk.maemo.org/showthread.php?t=34301)

CoreFusion 2009-11-11 23:55

Question: Accelerometer accuracy
 
I had a crude idea for an application and now have a question about the accelerometer accuracy. How precisely can the N900 tell it's orientation in all directions? For example can it tell when it's in straight level horizontally and straight up vertically... I'll try to draw a picture what I'm after.. that'll be easier (hopefully, as I'm not an artist :p)

https://gen2.dnsdojo.net/~corefusion/orientation.png

baksiidaa 2009-11-12 01:57

Re: Question: Accelerometer accuracy
 
Do you want accuracy or precision?
Precision: 8 bits over -2 to +2 g, which is about 16 mg for the LSB, which works out to give you about 1 degree resolution.
Accuracy: The zero-offset is +/-40 mg, or just under 3 degrees.

Take-home answer: You can tell how well you are oriented to vertical to within about 3 degrees. You can measure rotation differences of about 1 degree.

Specs taken from datasheet at http://www.st.com/stonline/products/...6/lis302dl.htm

baksiidaa 2009-11-12 02:04

Re: Question: Accelerometer accuracy
 
The zero-offset might be better if Nokia does any additional calibration. The datasheet doesn't seem to have anything about long-term stability though.


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