A free program for Android, by Motorola Mobility LLC..

With its ability to respond to hand gestures to accomplish tasks, Moto Actions is truly a huge time-saver for busy users. If you don’t want to be bothered by annoying phone calls and notifications, you can leave your device face down. 

Alternatively, you can enable vibrate by placing your phone face up. Two chopping motions will turn on your phone’s flashlight, whereas twisting your wrist twice will enable your camera. When you download this app, you’ll be greeted with a brief tutorial on each gesture. It even has a “try it out” button to ensure mastery. Most importantly, Moto Actions doesn’t log or collect your personal data.