This is a great idea. Unfortunately, there are a lot of small issues that add up to a rather frustrating product.
It needs a better bearing, it should be a bit heavier, it doesn't really work without the plastic insert that goes into the bearing, and the bearing is too small to use just with your fingers. The creator said they didn't include the plastic insert because you can "print one yourself!" I thought this was because it would work without that piece, but this is not the case. The ir needs a really tight clearance to trigger and your finger alone isn't enough to do this reliably. That and the bearing is much smaller than a normal fidget spinner, which makes it hard to use just with your fingers. Finally, due to the bearing and the mass, it doesn't spin very long. For one the bearing feels very cheap and seems to have a lot of friction which slows the spinner down. Additionally, the spinner itself is light. The creator added a washer (not present in the tindie pics) to it in an attempt to help this, but it's still no where near heavy enough. I can reliably get it to spin fast enough for POV to work for about maybe 5 seconds after which the spinner slows down too much.
A few small improvements would make an excellent product: - Switch to a standard fidget spinner bearing so that normal fingers can use it - Add weights to the ends of the spinner to give it more inertia - Include bearing inserts so that the ir sensor triggers reliably - Switch to a higher quality bearing with less friction so that it spins a long time