Researchers from Disney Research, Carnegie Mellon, and MIT have figured out a way to increase the speed and accuracy of tracking wireless, battery-less RFID tags. They've used the discovery to create a bunch of cool, interactive objects that don't need a power source, including wireless pong controllers, an interactive wood-block tic-tac-toe game, and an unpowered music synthesizer — all using a version of the tech inside Disney's RFID-powered MagicBands.

The work uses a type of RFID tag that's powered solely by radio frequencies that are emitted by an external reader. Prior research has shown that RFID tags could be used to reliably track inputs like when a person touched a tagged object, whether the object was touching conductive or dialectic materials, and whether or not the tagged object was in motion. The problem with these approaches has been a significant time delay required to track objects accurately. Low power signals produced by RFID tags have required multiple reads, resulting in delays of up to two minutes — making real-world applications impractical. But the researchers from Disney combined probabilistic modeling and a Monte Carlo-based sampling method to deliver readings with typical delays of 200 milliseconds. The method is also able to determine if a tag is covered, and the speed at which it's traveling, which allowed the researchers to demonstrate some pretty interesting applications.