Just in case, We did calibrate our phones. E.g. My phone's Gravity value is more like 8.7 vs 9.81. While static, the phone's accel values were acceptable. As soon as the phone was in motion, the acceleration (position) data went out to lunch.
FYI, marketing = lying 99% of the time. IMO On Jul 9, 1:05 pm, dilit <[email protected]> wrote: > We are writing an application that uses acceleration sensor data to > plot phone's movement in 3D. > We are finding gross inconsistencies in the actual data output by the > sensor. Also, sampling rates > vary greatly from 8 to 200 millis. (using System.currentTimeMillis()) > > Specifically, when we try to draw a circle with G1 flat on the table > all the time (filtering out gravity accel 9.8), > most of the time we would get a plot of phone's position that is not a > circle at all. Lots of times, it would be close to a straight line. > Sometimes, it would start drawing an arc, but would not close the > circle shooting off in a random direction. > > We tried to eliminate the time variable, by substituting a constant > time sampling rate (10 millis) to calculate phones position, but the > result was > very close to what we had before (shapewise). Also, the acceleration > in Z direction when the phone is displaced lying flat on a table (XY > plane) varies too > by +/- 2 units which is a lot. > > I do not think it is an error in our code, as we have checked it many > times. If there were an error indeed and the > accelerometer worked properly, we would see a consistently wrong > depiction of the phone's movement. Unfortunately, repeating the same > movement > (circle) would produce sometimes wildly differently shaped plots. > > It all comes down to us wanting to know if that is indeed the case > that the G1 accelerometer is very unreliable and inconsistent device > when used for more or less precise > measurements? Is there some documentation/facts paper that would tell > us just how reliable accelerometer is? > > Thanks for you help! > Dmitriy --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-developers?hl=en -~----------~----~----~----~------~----~------~--~---
