3D-printed objects connect to internet without any electronics

Typically, devices require electronic components to send, interpret and receive signals via Wi-Fi. Given this, wirelessly connecting 3D-printed devices without the addition of electronic components had never been achieved.

“Our goal was to create something that just comes out of your 3D printer at home and can send useful information to other devices,” said Vikram Iyer, a graduate student at the University of Washington.

“But the big challenge is how do you communicate wirelessly with Wi-Fi using only plastic? That’s something that no one has been able to do before.”

In order to allow their printed devices to exchange information, the University of Washington engineers harnessed backscatter techniques, which use antennas to reflect radio waves or other signals emitted from a device such as a Wi-Fi router. These techniques are often employed in extremely low-power devices, such as battery-free watches.

The researchers were able to contain a makeshift antenna in a conductive object printed in plastic and copper. They replaced other electrical components – such as sensors – with moving, 3D-printed springs, gears, switches and other mechanical parts.

An action such as pushing a button triggers movements of these components; in turn causing a switch of conductive material to connect with the antenna for varying lengths of time. This results in a change in the antenna’s reflective state, creating a pattern of signals which are detected by a Wi-Fi receiver.

“As you pour detergent out of a Tide bottle, for instance, the speed at which the gears are turning tells you how much soap is flowing out. The interaction between the 3D-printed switch and the antenna wirelessly transmits that data,” said Professor Shyam Gollakota, senior author of the study.

“Then the receiver can track how much detergent you have left and when it dips below a certain amount, it can automatically send a message to your Amazon app to order more.”

Using a 3D-printing ink that combines plastic with iron, the team were also able to create objects with magnetic properties. This allowed them to encode information in the objects, such as barcode identification.

The researchers plan to make their CAD models publicly available, such that anyone with access to a 3D printer can create their own devices from commercially available plastics. As well as a set of components – such as buttons and sliders – the University of Washington team designed a water flow meter, scale, and wind meter.

The team hopes that eventually this technique could make it possible to create a smart system of “talking objects” capable of interacting with their surroundings.