Not every hand gesture is universal. And sometimes, making what you think is an innocent gesture in one country can land you in hot water somewhere else. Just ask any traveler who's given a thumbs ...

An curved arrow pointing right. Many hand gestures in the US are pretty universal. The peace sign, thumbs up, and "devil horns" aren't likely to earn you any strange looks in the States ...

[B. Aswinth Raj] wanted to control a VLC player with hand gestures. He turned to two common ultrasonic sensors and Python to do the job. There is also, of course, an Arduino. You can see a video ...