title: g sensor(accelerometer) curve on HTC One M8
body: <p>I used to extract accelerometer data by android SDK on Samsung Galaxy S4,
  and I encounter a strange problem when I change platform to HTC One M8.</p>
  
  <p>Here is the statement about the experiment:
  Once I move the device from place A to place B straight(negative direction of device), I will read the accelerometer data and compute the displacement between A and B.
  The curve of acceleromter data on S4 is correct.
  It contains two pick with different sign and the shape like 'S' lie on the floor.</p>
  
  <p>But when I use M8, it give me the curve which is wrong obviously. it looks like 'W'
  P.S. The motion and program of two are totally the same.</p>
  
  <p>Can anyone give me some reason to the difference? 
  Is the g-sensor on M8 is the problem?
  I'm really stuck on it.
  thanks. </p>