In first, 3-D printed objects connect to WiFi without electronics

In first, 3-D printed objects connect to WiFi without electronics
UW engineers have developed the first 3-D printed plastic objects that can connect to other devices via WiFi without using any electronics. The 3-D printed attachment above can sense how much laundry soap is being used -- and automatically order more when the bottle is running low. Credit: Mark Stone/University of Washington

Imagine a bottle of laundry detergent that can sense when you're running low on soap—and automatically connect to the internet to place an order for more.

University of Washington researchers are the first to make this a reality by 3-D printing plastic objects and sensors that can collect useful data and communicate with other WiFi-connected devices entirely on their own.

With CAD models that the team is making available to the public, 3-D printing enthusiasts will be able to create objects out of commercially available plastics that can wirelessly communicate with other smart devices. That could include a battery-free slider that controls music volume, a button that automatically orders more cornflakes from Amazon or a water sensor that sends an alarm to your phone when it detects a leak.

"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," said co-lead author and UW electrical engineering doctoral student Vikram Iyer. "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."

The system is described in a paper presented Nov. 30 at the Association for Computing Machinery's SIGGRAPH Conference and Exhibition on Computer Graphics and Interactive Techniques in Asia.

UW electrical engineers and computer scientists have developed the first 3-D printed plastic objects that can connect to other devices via WiFi without using any electronics. Credit: University of Washington

To 3-D print objects that can communicate with commercial WiFi receivers, the team employed backscatter techniques that allow devices to exchange information. In this case, the team replaced some functions normally performed by electrical components with mechanical motion activated by springs, gears, switches and other parts that can be 3-D printed—borrowing from principles that allow battery-free watches to keep time.

Backscatter systems use an antenna to transmit data by reflecting radio signals emitted by a WiFi router or other device. Information embedded in those reflected patterns can be decoded by a WiFi receiver. In this case, the antenna is contained in a 3-D printed object made of conductive printing filament that mixes plastic with copper.

Physical motion—pushing a button, laundry soap flowing out of a bottle, turning a knob, removing a hammer from a weighted tool bench—triggers gears and springs elsewhere in the 3-D printed object that cause a conductive switch to intermittently connect or disconnect with the antenna and change its reflective state. Information—in the form of 1s and 0s—is encoded by the presence or absence of the tooth on a gear. Energy from a coiled spring drives the gear system, and the width and pattern of gear teeth control how long the backscatter switch makes contact with the antenna, creating patterns of reflected signals that can be decoded by a WiFi receiver.

In first, 3-D printed objects connect to WiFi without electronics
The UW team of computer scientists and electrical engineers also 3-D printed plastic scroll wheels, sliders and buttons that can wirelessly interact with computers, phones and other WiFi-connected devices. Credit: Mark Stone/University of Washington

"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 3-D printed switch and antenna wirelessly transmits that data," said senior author and Allen School associate professor 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 from the UW Networks & Mobile Systems Lab 3-D printed several different tools that were able to sense and send information successfully to other connected devices: a wind meter, a water flow meter and a scale. They also printed a flow meter that was used to track and order laundry soap, and a test tube holder that could be used for either managing inventory or measuring the amount of liquid in each test tube.

They also 3-D printed WiFi input widgets such as buttons, knobs and sliders that can be customized to communicate with other smart devices in the home and enable a rich ecosystem of "talking objects" that can seamlessly sense and interact with their surroundings.

In first, 3-D printed objects connect to WiFi without electronics
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). Credit: University of Washington

Using a different type of 3-D printing filament that combines plastic with iron, the team also leveraged magnetic properties to invisibly encode static information in 3-D printed objects—which could range from barcode identification for inventory purposes or information about the object that tells a robot how to interact with it.

"It looks like a regular 3-D printed but there's invisible information inside that can be read with your smartphone," said Allen School doctoral student and co-lead author Justin Chan.

  • In first, 3-D printed objects connect to WiFi without electronics
    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. Credit: Mark Stone/University of Washington
  • In first, 3-D printed objects connect to WiFi without electronics
    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. Credit: Mark Stone/University of Washington

Explore further

Team shatters long-range communication barrier for devices that consume almost no power

More information: Paper:
Citation: In first, 3-D printed objects connect to WiFi without electronics (2017, December 5) retrieved 25 August 2019 from
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User comments

Dec 05, 2017
Amazing tech!
(Lowering the cost of ways "your" stuff can spy on you for its real masters...)

Dec 05, 2017
"...without electronics"?? Antennas and switches are electronic devices. Still very clever. But not really a new idea - look up US Embassy bugging by the Soviets with "Infinity Transmitter".

Dec 05, 2017
I wonder how small these things can be made. I am thinking about making a biosuit that tracks joint motions in my garage. If I can create a unique sensor pattern for every joint, and make the thing small enough, I can make all the sensors right in my home shop with only the expense of the plastic itself.

Dec 05, 2017
Great so since it's not programmable I spam my neighbors' WiFi routers with unrouted IoT messages, not to mention my own!!!??!?

Never mind security.

Dec 05, 2017
Pretty darn cool. I agree with Da Schneib though. You could spoof a signal from the IOT to your receiver. A powerful RF spoofed signal acting as a switch (as the video shows) could open all kinds of doors. However, in the right application it might be a perfect solution.

Dec 05, 2017
What you want to be sure of is that it's not a quick-n-dirty solution. If you can make each transponder have a unique address then you can have a router for them that you program to only listen for yours. But again, security. Now your neighbor can make money from a manufacturer who gets them to aggregate data from all the houses around them. Further applications left to the observer.

Remember that likely producers of such objects will most likely be the manufacturer of the supply that is being consumed, who will have an interest in your data. If this doesn't make you uncomfortable you haven't thought your way through it yet.

Dec 06, 2017
Great so since it's not programmable I spam my neighbors' WiFi routers with unrouted IoT messages, not to mention my own

I don't think it would be that useful. First you'd have to listen in on what your neighbor is 'sending'. Then you have to play that back...but since the signal has no identifier you don't really know what you'd be sending.

You could potentially prank someone - but you wouldn't know what you're pranking them with.

Dec 06, 2017
and automatically order more when the bottle is running low
Try to imagine, that this bottle will leak in your bathroom and it will wipe-out your bank account in similar way, like the mobile phone with unlimited credit on roaming. You will return from holiday and find pile of Amazon packages before your home (all delivered automatically with drones indeed).

That would be impossible. Read the article, it explains how the sensor works.

It cannot sense how much the bottle contains, it estimates how much you pour out, if the bottle leaks it will just run dry before the sensor realizes it and you will be stuck without softener.

Dec 06, 2017
I have to give them Kudos for ingenuity but I cannot fathom how it would work in real life. Most people are lucky to have Wi-Fi coverage in their entire home with one router. That is with active devices pumping out milliwatts of power. Also, how does a piece of plastic acquire the IP address needed to be accepted by a network when most home routers assign IP addresses on a temporary basis. Just Saying.

Dec 06, 2017
In order to transmit a Wi-Fi packet with a unique address there need to be some active logic circuitry involved. This device is just modulating the RF of the existing packets and a receiver is reading the modulated RF. It would be pretty hard to give each unit a unique identity.

Dec 06, 2017
The fact is that they could do the same thing with any RF transmitter and receiver. They are just amplitude modulating a RF carrier by changing how much signal is reflected to the receiver. Anywho, I hope the get an A on their term paper.

Dec 09, 2017
It is only a matter of years before everyone will be required to have a chip embedded in their body. The government will create mass riots and confusion. People will willingly stand in line for the procedure for "public safety" reasons. After all "Its for the safety of the children!".

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