Dr. Rehmi Post’s presentation at the Natural Science and Mathematics Colloquium on Wednesday, titled Clothes that Generate Power: the Sp4rkl3 Shirt, focused on the creative uses of static electricity to generate power for simple, sewn circuitry, and its potentially shocking impact on the science-fashion industry.
Post, currently working in the media lab of the Massachusetts Institute of Technology, began following his interest in wearable technology in 1997, when he earned his Master’s Degree in Science for his work on the technology, called “e-broidery” at the time, at MIT.
What began as an investigation into washable electronics equipment quickly developed into the search for effective metallic textiles.
“I didn’t want to look like that much of a dork,” said Post, as he referred to a former colleague known for wearing sophisticated computer units involving backpacks and high-tech helmets.
After advancing the ideas of soldering simple circuits onto copper underwire and the metallic ribbons of the Indian sari, Post further explored the e-textiles field with the hopes of daring the impossible: removing the batteries.
With the need for better circuitry came the design of denim sewing, where a semiconducting fabric of 85% polyester and 15% steel fiber was strung into two-plied yarn for sewing onto the same material used to make jeans.
These fibers were run from the conductive steel wire to mini circuit boards that, in turn, were in contact with a midi synthesizer, allowing for sounds to be generated based on where pressure was applied to the circuit board.
After finishing a post-doctoral thesis on an inertial sensor at MIT, Post again returned to electronic textiles, bringing with him the idea of electrostatics as a means of powering simple circuits without an alternative power source.
“I had this crazy idea that you could get rid of static electricity,” said Post.
Post and his colleagues at MIT eventually released “Sp4rkl3,” a skirt whose fabric panels build enough charge to activate circlets of 32-bulb LED lights at the waist.
Its circuitry is based on the idea of “triboelectricity”, that two surfaces of opposite “charge” (tendency to build up positive or negative charge upon contact and separation) can act as a circuit-like capacitor to generate electrical power.
While static-based (creating only about 650 millijoules of power), it is enough to operate simple circuits, like small lights and capacitors.
On Sp4rkl3, Post said “we also want to start to see how we can manufacture this.” Unfortunately, this seems to be the difficult part of the industry.
The fabrics are designed with traditional methods, mostly sewing with sewing machines rather than through industrialized processes.
Also, given the electrical nature of the clothing, improper assembly could potentially shock the user, even if only with a small voltage.
Post concluded his presentation, given to the large audience of students, faculty, and community members in the Schaefer Lecture Hall, with a discussion of current projects, and his lab’s plans to optimize power and circuitry elements (including diode separations) to create more efficient electronic textiles.
“I thought the lecture was quite interesting,” said Elliot Russell, a senior who attended the lecture. “I thought the method through which Dr. Post was harvesting the static electric energy was very intriguing.”
“I think his work is pretty neat,” said Charles Adler, chair of the Physics Department and head of the NS&M colloquium Series. “It’s not just that he is looking into a really interesting idea, but that he is also trying to make solutions which work with off-the-shelf technology which everyone has access to.”
The next lecture of the NS&M Colloquium Series will be on Sept. 22, titled Mathematics Makes More Kidney Transplants Possible, and will be given by Sommer Gentry from the U.S. Naval Academy.