The so-called “Internet of Things” is the idea of having everyday objects communicating useful information over the internet for a variety of purposes. For instance, an internet-connected refrigerator might be able to order a grocery delivery if you start running low on certain items.
The Internet of Things concept has largely focused on the idea of embedding electronics into everyday items, but researchers at the University of Washington recently developed a way to connect 3D-printed objects to the internet without the use of electronics, according to a new paper presented at last month’s SIGGRAPH Conference and Exhibition on Computer Graphics and Interactive Techniques in Asia.
To create objects that can connect with standard WiFi receivers, the team used backscatter methods that allow devices to send data by reflecting WiFi signals back to their source. To achieve this, the team used mechanical springs, gears and other parts that were 3-D printed to perform functions typically done by electrical parts.
Backscatter systems utilize an antenna to deliver information via reflected WiFi signals, and data baked into those reflected patterns can be deciphered by a WiFi receiver. In this instance, the antenna inside a 3-D printed object is made of conductive printing filament that blends plastic with copper.
In the study team’s novel system, physical action – such as the pressing of a button or liquid flowing out from a container – activates gears and springs somewhere in the 3-D printed item, causing a conductive switch to alternately connect or disconnect with the WiFi receiver via its reflective state.
Physical action drives a coiled spring that turns a gear to encode binary data. The size and pattern of gear teeth determine how long the backscatter switch connects with the antenna, making patterns of 1s and 0s that can be deciphered by a WiFi receiver.
The study team said they used their system to create a flow meter that could track and order liquid laundry soap. Study author Shyam Gollakota, an associate professor of computer science and engineering, said the speed at which gears are turning tells how much soap is flowing out of the detergent bottle.
The interaction between the 3-D printed switch and antenna wirelessly transmits that data. 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.
Shyam Gollakota, Associate Professor of Computer Science and Engineering
In addition to making a flow meter, the study team was also able to make a wind meter and a scale that could also impart electronics-free WiFi connectivity. Buttons, knobs and sliders also printed by the team could be customized to create a menagerie of connected objects that could seamlessly detect and interact.
Using another kind of 3-D printing filament that blended plastic with iron, the team also utilized magnetic qualities to invisibly write static data inside 3-D printed items, which could cover anything from barcode identification for a store to instructions for a warehouse robot.
The study team said they wanted to make designs that the general public could easily take advantage of, such as flow sensors that detect leaky pipes or a slider to control music volume.
Our goal was to create something that just comes out of your 3-D printer at home and can send useful information to other devices. But the big challenge is how do you communicate wirelessly with WiFi using only plastic? That’s something that no one has been able to do before.
Vikram Iyer, Electrical Engineering Doctoral Student, University of Washington