I'm wondering if anyone can either find more details of the design, or offer a decent explanation of how it works. Is the sand driving a small generator inside, similar to how the GravityLight
works? If so, is this a fairly novel mechanism (in that it's driven by sand), or does this kind of thing exist elsewhere?
The science and design press lets us down a bit since they seem to be satisfied with "kinetic energy" and ask no further questions. It is implied that there is a working prototype, but I couldn't find confirmation of this, or a video.
Another description from Danielle Trofe Design's website.