title: madgwick/ mahony Axes convention
body: <p>I have problem which mahony/ madgwick implementation</p>
  
  <p>Could someone say something about that</p>
  
  <p><a href="http://i.stack.imgur.com/V9B2v.png" rel="nofollow">MPU-9250</a></p>
  
  <p>MadgwickQuaternionUpdate(ax, ay, az, gx, gy, gz, my, mx, mz);</p>
  
  <p>and another example</p>
  
  <p><a href="http://api.ning.com/files/4Epf-T61UHP41R5kTSFUGZGG6Y5QUaIJsZX7p6NHlqqaLunj1GGg5sE1roq0ssP4yS7Sp*7jmI2vr8P5N561hYwSloZoWx76/BNO055.jpg" rel="nofollow">BNO-055</a></p>
  
  <p>MadgwickQuaternionUpdate(ax, ay, az, gx, gy, gz, mx, my, mz);</p>
  
  <p>code comes from github user kriswiner</p>
  
  <p>in first example Z axis is negated and it is +mz in function.</p>
  
  <p>in second example Z axis is normal and it is +mz in function.</p>
  
  <p>I think one is bad?
  Which ones is bad?</p>