By RealityCap http://www.realitycap.com
A simple level app for iOS that illustrates how to perform calibration on the accelerometer.
This app was created in response to the iPhone 5S accelerometer problem, detailed in these posts: http://www.realitycap.com/iphone-5s-accelerometer/ http://www.realitycap.com/iphone-5s-accelerometer-part2/