Now you can 3D-print things that connect to Wi-Fi without batteries or electronics

Researchers at the University of Washington have created a range of 3D-printed plastic objects that can communicate with a router even though they're not connected to the internet and don't contain any electronics.

The technique the researchers used to enable 3D-printed Wi-Fi is called 'Wi-Fi backscatter'. It typically relies on electronic components to reflect or absorb radio signals from a Wi-Fi router.

They substituted electrical components with printable springs, gears and switches using plastic, while an antenna was printed with a conductive 3D-printing filament made of plastic and copper.

The idea is to print things like a sensor for a washing detergent bottle that can detect when it's running low and communicate with a smartphone for reordering supplies.

The printed gear system encodes the 0s and 1s via the presence or absence of teeth in a plastic cog. The setup is also connected to a coil that toggles a switch made of conductive plastic that changes the state of the antenna.

Placed on a detergent bottle, the speed at which the gears turn estimates how much liquid is flowing out. A receiver can then monitor the bottle's level and send a message to a smartphone app when it falls below a certain level.

The researchers also printed a wind meter, a water flow meter, and a scale, as well as various widgets such as buttons, knobs, and sliders.

Another technique they used to make 3D components that can communicate with smart devices was to create 3D-printed MagLink objects, which are encoded with magnetic fields.

For this system, the researchers used a Nexus 5's magnetometers to receive data from the objects. The two different states are determined by the materials used to print the object. For 0 they used plastic and for a 1 they used a ferromagnetic plastic consisting of iron filings.

The researchers have released designs for the components as well as links to sources for materials.

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