The UW team also 3-D printed plastic scroll wheels, sliders and buttons that can wirelessly interact with computers, phones and other WiFi-connected devices.

In this backscatter system, an antenna embedded in a 3-D printed object (middle) reflects radio signals emitted by a WiFi router (left) to encode information that is “read” by the WiFi receiver in a phone, computer or other device (right).

The 3-D printed gears (in white) and spring (blue spiral) toggle a switch (white box with grey surface) made of conductive plastic. The switch changes the reflective state of a 3-D printed antenna (gray strip) to convey useful data to a WiFi receiver. The shape of the gears and the speed at which they move encode the digital data.

The UW team also demonstrated how to use the magnetic properties of some 3-D printed material to invisibly encode static data in the objects above, which could be useful for inventory tracking or to help robots interact with them.

The research team. Left to right: UW electrical engineering doctoral student Vikram Iyer, Paul G. Allen School of Computer Science & Engineering associate professor Shyam Gollakota, and Allen School doctoral student Justin Chan.