Tag Archives: Joshua Smith

Singing posters and talking shirts can communicate with you via car radio or smartphones

Singing posters and talking shirts haven’t gone beyond the prototype stage yet but I imagine University of Washington engineers are hoping this will happen sooner rather than later. In the meantime, they are  presenting their work at a conference according to a March 1, 2017 news item on ScienceDaily,

Imagine you’re waiting in your car and a poster for a concert from a local band catches your eye. What if you could just tune your car to a radio station and actually listen to that band’s music? Or perhaps you see the poster on the side of a bus stop. What if it could send your smartphone a link for discounted tickets or give you directions to the venue?

Going further, imagine you go for a run, and your shirt can sense your perspiration and send data on your vital signs directly to your phone.

A new technique pioneered by University of Washington engineers makes these “smart” posters and clothing a reality by allowing them to communicate directly with your car’s radio or your smartphone. For instance, bus stop billboards could send digital content about local attractions. A street sign could broadcast the name of an intersection or notice that it is safe to cross a street, improving accessibility for the disabled. In addition, clothing with integrated sensors could monitor vital signs and send them to a phone. [emphasis mine]

“What we want to do is enable smart cities and fabrics where everyday objects in outdoor environments — whether it’s posters or street signs or even the shirt you’re wearing — can ‘talk’ to you by sending information to your phone or car,” said lead faculty and UW assistant professor of computer science and engineering Shyam Gollakota.

“The challenge is that radio technologies like WiFi, Bluetooth and conventional FM radios would last less than half a day with a coin cell battery when transmitting,” said co-author and UW electrical engineering doctoral student Vikram Iyer. “So we developed a new way of communication where we send information by reflecting ambient FM radio signals that are already in the air, which consumes close to zero power.”

The UW team has — for the first time — demonstrated how to apply a technique called “backscattering” to outdoor FM radio signals. The new system transmits messages by reflecting and encoding audio and data in these signals that are ubiquitous in urban environments, without affecting the original radio transmissions. Results are published in a paper to be presented in Boston at the 14th USENIX Symposium on Networked Systems Design and Implementation in March [2017].

The team demonstrated that a “singing poster” for the band Simply Three placed at a bus stop could transmit a snippet of the band’s music, as well as an advertisement for the band, to a smartphone at a distance of 12 feet or to a car over 60 feet away. They overlaid the audio and data on top of ambient news signals from a local NPR radio station.

The University of Washington has produced a video demonstration of the technology

A March 1, 2017 University of Washington news release (also on EurekAlert), which originated the news item, explains further (Note: Links have been removed),

“FM radio signals are everywhere. You can listen to music or news in your car and it’s a common way for us to get our information,” said co-author and UW computer science and engineering doctoral student Anran Wang. “So what we do is basically make each of these everyday objects into a mini FM radio station at almost zero power.”

Such ubiquitous low-power connectivity can also enable smart fabric applications such as clothing integrated with sensors to monitor a runner’s gait and vital signs that transmits the information directly to a user’s phone. In a second demonstration, the researchers from the UW Networks & Mobile Systems Lab used conductive thread to sew an antenna into a cotton T-shirt, which was able to use ambient radio signals to transmit data to a smartphone at rates up to 3.2 kilobits per second.

The system works by taking an everyday FM radio signal broadcast from an urban radio tower. The “smart” poster or T-shirt uses a low-power reflector to manipulate the signal in a way that encodes the desired audio or data on top of the FM broadcast to send a “message” to the smartphone receiver on an unoccupied frequency in the FM radio band.

“Our system doesn’t disturb existing FM radio frequencies,” said co-author Joshua Smith, UW associate professor of computer science and engineering and of electrical engineering. “We send our messages on an adjacent band that no one is using — so we can piggyback on your favorite news or music channel without disturbing the original transmission.”

The team demonstrated three different methods for sending audio signals and data using FM backscatter: one simply overlays the new information on top of the existing signals, another takes advantage of unused portions of a stereo FM broadcast, and the third uses cooperation between two smartphones to decode the message.

“Because of the unique structure of FM radio signals, multiplying the original signal with the backscattered signal actually produces an additive frequency change,” said co-author Vamsi Talla, a UW postdoctoral researcher in computer science and engineering. “These frequency changes can be decoded as audio on the normal FM receivers built into cars and smartphones.”

In the team’s demonstrations, the total power consumption of the backscatter system was 11 microwatts, which could be easily supplied by a tiny coin-cell battery for a couple of years, or powered using tiny solar cells.

I cannot help but notice the interest in using this technology is for monitoring purposes, which could be benign or otherwise.

For anyone curious about the 14th USENIX Symposium on Networked Systems Design and Implementation being held March 27 – 29, 2017 in Boston, Massachusetts, you can find out more here.

Battery-free wireless devices and a true internet of things in our future say University of Washington (state) scientists

An Aug. 13, 2013 University of Washington (state) news release by Michelle Ma (also on EurekAlert) features a technique that could render batteries for a new wireless communication network unnecessary,

University of Washington engineers have created a new wireless communication system that allows devices to interact with each other without relying on batteries or wires for power.

The new communication technique, which the researchers call “ambient backscatter,” takes advantage of the TV and cellular transmissions that already surround us around the clock. Two devices communicate with each other by reflecting the existing signals to exchange information. The researchers built small, battery-free devices with antennas that can detect, harness and reflect a TV signal, which then is picked up by other similar devices.

The technology could enable a network of devices and sensors to communicate with no power source or human attention needed.

“We can repurpose wireless signals that are already around us into both a source of power and a communication medium,” said lead researcher Shyam Gollakota, a UW assistant professor of computer science and engineering. “It’s hopefully going to have applications in a number of areas including wearable computing, smart homes and self-sustaining sensor networks.”

The researchers published their results at the Association for Computing Machinery’s Special Interest Group on Data Communication 2013 conference in Hong Kong, which began Aug. 13 [2013]. They have received the conference’s best-paper award for their research.

“Our devices form a network out of thin air,” said co-author Joshua Smith, a UW associate professor of computer science and engineering and of electrical engineering. “You can reflect these signals slightly to create a Morse code of communication between battery-free devices.”

Here’s a little information about the technique (from the new release),

The researchers tested the ambient backscatter technique with credit card-sized prototype devices placed within several feet of each other. For each device the researchers built antennas into ordinary circuit boards that flash an LED light when receiving a communication signal from another device.

Groups of the devices were tested in a variety of settings in the Seattle area, including inside an apartment building, on a street corner and on the top level of a parking garage. These locations ranged from less than half a mile away from a TV tower to about 6.5 miles away.

They found that the devices were able to communicate with each other, even the ones farthest from a TV tower. The receiving devices picked up a signal from their transmitting counterparts at a rate of 1 kilobit per second when up to 2.5 feet apart outdoors and 1.5 feet apart indoors. This is enough to send information such as a sensor reading, text messages and contact information.

It’s also feasible to build this technology into devices that do rely on batteries, such as smartphones. It could be configured so that when the battery dies, the phone could still send text messages by leveraging power from an ambient TV signal.

The applications are endless, the researchers say, and they plan to continue advancing the capacity and range of the ambient backscatter communication network.

The researchers have a produced a video demonstrating  ambient backscatter (for anyone not familiar with the term RF, it’s radio frequency),

If I understand this rightly, ambient backscatter takes advantage of the signals already present in the atmosphere, which means these new battery-free devices are dependent on other devices which do need batteries, cell towers, etc.(ETA Aug. 1, 2013:  as well as wireline] devices otherwise there won’t be any ambient backscatter.