This online drum machine app is beta, feel free to send suggestions or bug reports to me
Apple has turned off motion sensor in Safari by default.
Use Chrome or go to Settings > Safari > Motion & Orientation
and turn it on and reload page to be able to use the virtual drums.
Open this page on an iPhone to play virtual drums with your phone
PS. If you upload a video playing with your phone on Youtube
tagged with onemotion I will put it here.