This is an interface which can control a smartphone by knocking or tapping on the phone, even while it's still in your pocket. Robust implementation that rarely produces false positives. Source code includes an example for controlling media playing apps in Android like Skype, Pandora and almost all other similar apps.
See project homepage for full description, explanation and presentation slides.
by Torgeir Lien (samma@github / sloooth@gmail.com)