title: Android tap on device body sensor
body: <p>following the <a href="http://www.knocktounlock.com/" rel="nofollow">KnockToUnlock</a> Iphone app video,
  I was wondering what would be the best sensor to utilize for detecting tapping on a device body?</p>
  
  <p>Also what would be it's sensitivity? i.e , can i detect a tap on the side of the device and a tap on the back of a device?</p>