From their forum here: http://www.duo3d.com/forums/viewthread/9/

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Well first and foremost the biggest difference is we believe that everyone should be able to make and understand our sensors. That is why we focus on a DIY solution keeping the cost as low as possible. We also believe that people should have these devices as soon as possible and not have to wait. That is why we are going for a Kickstarter project so we can get the community involved in making awesome open hardware.

As for the technical details we use a independently discovered and developed methods to perform our tracking. Further more we are not only limited to hand/finger tracking but our algorithms allow for other potential tracking scenarios that are still unexplored.

There really is very little in terms of hardware in a Leap Motion. It's basically two webcam grade cameras, 3 infra-red LEDs and a plastic IR filter. This is just the same thing.