Keeping in mind the variety on offer, we've listed lightweight portable projectors with built-in batteries that work well with your smartphone and are priced under $500 at the time of writing.

An curved arrow pointing right. It's really simple to build a projector for your smartphone to be able to project the same types of holograms seen in Star Wars and other movies. Here's how!

Those projects fizzled out, most likely due to the cost of the projectors, but we got a few laughs out of it: that wearable smartphone that projected a screen onto your wrist used the same technology.