LeapMotion is a USB device now available for pre-order that “creates a 3D interaction space of 8 cubic feet to precisely interact with and control software on your laptop or desktop computer.” According to the website

The Leap senses your individual hand and finger movements independently, as well as items like a pen. In fact, it’s 200x more sensitive than existing touch-free products and technologies. It’s the difference between sensing an arm swiping through the air and being able to create a precise digital signature with a fingertip or pen.

The video embedded above shows it off pretty nicely. The device itself is about the size of the power brick that comes with the Mac Minis or the AppleTV (or used to). It’s, not coincidentally, similarly designed, so it’s not going to look like some ugly chunk of plastic and LEDs on your desk. This is, I think, not to be underestimated if you are asking people to invest in a new kind of interface that will, indeed, sit on their desk to be stared at all day. People are pretty pernickety about what goes on their desk.

When I say invest in, I’m really talking about time. The device itself is pretty cheap at $69.99. I can see this being a bonanza for people making interactive installations and performative interfaces (which is why I came across it, thanks to Joel Gethin Lewis).

It looks like LeapMotion is responsive and accurate, but there is still the question of holding your hands in front of you all day. With a desktop version, I foresee an elbows-resting-on-the-table-while-wiggling-the-hands mode of usage. Perhaps it’s time to invest in an elbow rest Kickstarter project.