Passive Sensors and Printed Sensors

E-mail Melanie Martella

All I need is another week or so in the year so that I actually have time to seriously research new-to-me sensing topics. Like, say, the glorious world of printed electronics which keeps coming up with crazy cool breakthroughs. I mean, come on, sensors printed onto a wet suit? That's clever, right? Likewise Georgia Tech's paper-based wireless sensor for explosives. And that is very much the tip of the iceberg.

At the 2011 Sensors Expo and Conference, Raghu Das of IDTechEx, presented the second day keynote on the topic of printed electronics and it pretty much blew my mind. The range of printed electronics that are already available is impressive; but I'm less interested in printed displays than I am in printed sensors and what you can achieve with them. (There's also the fact that I'm a fan of materials engineering in pretty much all its forms, so the development of substrates and inks is fascinating to me, as is the whole notion of printing a device.)

In July of this year, Oak Ridge National Labs and ISA sponsored a workshop on passive wireless sensor tags. The final program is available here (PDF) and is well worth a read, not only to learn about the technologies involved, but to also get a feel for the scope of the applications. While not all of the tags described are printed, the workshop's focus on the capabilities presented by passive sensors is extremely educational. If you need an explanation of exactly how some of these passive sensors work, GE's overview of its Radio Frequency Sensing (RFS) (PDF). from the workshop is available by clicking the link.

Passive sensing opens up new markets and applications for sensors, expanding the range of options for people who want to acquire data about their processes or products. More sensors means more information that we can use. Here's where things get even more interesting. Printed Electronics Now recently published an interview with UC Berkeley professor Dr. Vivek Subramanian, who's been working in the field of printed electronics since 2000 and so has had a ringside seat as the field has developed. When Dr. Subramanian was asked where he saw the field of printed electronics heading, both in the near term and in 10 years, here's what he had to say: "I think there is a tremendous opportunity for printed electronics right now, as the deployment of smart phones has provided a ubiquitous computational device as well as a gateway to the cloud. Right now, Google and others use cell phones to determine traffic patterns, thus using cell phones as a representative of the physical world. Also, by using "bump," cell phones have the unique ability to transform their information to another cell phone via cloud-based database. These capabilities have the potential to enable a unique deployment opportunity for printed electronics."

Looks like the Internet of Things could get a lot more interesting, doesn't it?