Team creates 3D-printed objects that pick up Wi-Fi with no electronics

6 Dec 2017

The 3D-printed wheel powers the Wi-Fi signal to other devices. Image: Mark Stone/University of Washington

A breakthrough that enables 3D-printed objects to pick up Wi-Fi without electronics could usher in a new age of IoT in the home.

Internet of things (IoT) devices have been rapidly multiplying, and now a new development in 3D printing could turn everything in the home into a connected device.

The breakthrough was made by a team of researchers from the University of Washington, who revealed 3D-printed objects and sensors that can collect and send data with other Wi-Fi-connected devices without any need for electronics.

To do this, the team availed of ‘backscatter’ techniques, which allow devices to exchange information.

This means taking the function of electrical components in sensors and replacing them with mechanical motion-activated ones, such as springs, gears, switches and other parts that can be 3D printed, borrowing from principles that enable battery-free watches to keep time.

Backscatter systems use an antenna to transmit data by reflecting radio signals emitted by a Wi-Fi router or other device. Information embedded in those reflected patterns can be decoded by a Wi-Fi receiver.

In this case, the team’s antenna was contained in a 3D-printed object made of conductive printing filament, which mixes plastic with copper.

IoT detergent bottle

So, in some real-world examples, the turning of a knob or even detergent coming out of a bottle triggers gears and springs elsewhere in the 3D-printed object, causing a conductive switch to intermittently connect or disconnect with the antenna and change its reflective state.

The absence or presence of a tooth on the gear will trigger either a one or zero in binary while energy from a coiled spring drives the gear system and determines how long the backscatter will last.

“As you pour detergent out of a detergent 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 antenna wirelessly transmits that data,” said senior researcher Prof Shyam Gollakota.

“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.”

The team also 3D-printed Wi-Fi input widgets such as buttons, knobs and sliders, which can be customised to communicate with other smart devices in the home and enable an ecosystem of ‘talking objects’ that can seamlessly sense and interact with their surroundings.

Colm Gorey was a senior journalist with Silicon Republic