I saw this equation on internet, but i am not sure if it is correct and how to apply it...

Vout = Voffset + [(AV/Ag)x1gxsinB]

where:

Vout is the voltage readed into the analogical pin (calculated from the lecture from the 1024 levels)

Voffset is the voltage at 0g acceleration

AV/AG is the sensibility

g is the gravity on earth

and B is the tilt angle.

I suppose that Voffset is the voltage when the sensor is not in movement and the lecture in arduino is 512 --> 2.5Volts. Is it correct?

Other problem is how to know the sensibility AV/Ag. is it located in the datasheet?

i suppose that g could by 9.8 m/s^2, although an aprox. of 10 m/s^2 could be also valid.

So, in theory, the final equation to derive B is:

B = arcsin [(Vout-Voffset)/(AV/Ag)]

In theory we obtain the tilt angle B in degrees for one of the axis. If we repeat the calculation taking into account the values of the different pins, we could obtain the tilt for x, y and z

So, is it right?

UPDATE: here it is where is saw the equation:

http://www.freescale.com/files/sensors/doc/app_note/AN3107.pdfUPDATE 2: here there is more information

http://www.freescale.com/files/sensors/doc/app_note/AN3461.pdf