Building with E-Textiles, Part 2

Last week, I spent an afternoon diving into the wonderful world of e-textiles. That is to say that I spent several hours sewing electrical components into a garment in an attempt to learn something new about both textiles and interactive consumer electronics. What I discovered was a surprisingly vast industry poised to explode in popularity and market share in the next few years. The unique engineering challenges presented by wearable electronics represent a significant barrier to entry for any company seeking to break into this largely untapped market. That means those who do have the design expertise and engineering capability can fairly easily start to work with off-the-shelf components to build interesting new products. You know those shoes kids wear that have a little light that flashes every time they take a step? That’s just the beginning. Soon, you’ll start to see jeans with lights along the length of each leg. It starts with a little light. Then, it evolves into complex sequences of light pulses, and suddenly kids are using their clothes to communicate in an entirely new way.

So that’s all interesting and terrifying, but you’re really here for details on the light dancing gloves we’re making. Where do I begin? Ah, yes. Where part one ends, we had the light cluster sewn (installed?) in the right glove. Once I had a feel for the sewing, it was simply a matter of placing each component to minimize thread length. We were quite fortunate that the rest of the components fell naturally into place. With one exception, there are no crossing threads in the entire design. That is to say that there is only one point in the circuit layout where one trace must cross over another without intersecting it. Textiles make this a bit easier, since there are two sides of every fabric. Pass one thread over the other by punching through the fabric and running across the back side. This relies on the fabric to act as a suitable insulator between the two threads. We recommend avoiding designs that involve this sort of thing. It leads to complications and opportunity for substantial maintenance overhead in the event two threads make contact.

We were doubly fortunate, in that no one was wearing our finished glove when I melted a small section of polyester glove material while running a test. That would likely have resulted in a nasty burn. The material I melted was also coincidentally the only thing preventing the supply voltage from contacting the ground and shorting out the system. I was able to identify the problem and disconnect the power before that could happen, so no major harm done. Forensic analysis suggests the resistance of the circuit powering the lights is very low, resulting in excessive current through the common ground. We’ll be modifying the design to add a decorative (current-limiting) resistor between their common ground and the actual ground. This will prevent future melting, burning, cursing, and ancillary drama. The point is to have fun, not to learn triage techniques for 2nd degree burns. That will most likely happen tomorrow, as soon as I can find a suitable resistor to wire in.

Today, I bought a second pair of gloves to make a glove for myself. I’m calling this one the mark 2. After perusing the Home Depot utility glove section, I settled on Gorilla Grip. They are all black, except a little silver around the wrist. The XL fit me snugly, which was a surprise, as I expected a M or possibly L. These are interesting gloves. They feel like rubber, but they are 100% nylon. They’re very flexible, which makes the sewing much easier. I was able to sew all the components into the mark 2 gloves in about 3hrs, whereas the mark 1 gloves took almost 12hrs. To be fair, the mark 2 does have a simpler design with all the components on the back of the glove. Mostly, though, the reduced build time is largely due to complete lack of design and sewing proficiency for the mark 1. Now that I know more about the rules of this design medium, I’m already improving on the design.

Here’s a photo stream of the process: https://www.icloud.com/photostream/#A15oqs3qSqdIy

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Building with E-Textiles, Part 1

You know, I never thought I’d say this, but I am really excited to learn better sewing technique. And believe, me, coming from a mechanic/machinist/engineer that means a lot. Over the last few days, I’ve been working with the always-lovely Dr Sophia B Liu (http://sophiabliu.com) to design and fabricate a pair of gloves embedded with lights and accelerometers. We are building an interactive sculpture of sorts, where light is coupled with movement and gravity to create a visual experience. We are using a beautiful piece of hardware called a LilyPad Arduino, along with some sensors and lights, hoping to build something beautiful. Our first project is to couple the three axes of the accelerometer sensor to the three primary colors to produce motion-sensitive color.

After many hours of design discussion, finding a compromise between usability and ease-of-manufacturing, we began the tedious process of sewing our components into our gloves. As a sidenote, we got some great polyester 60s vintage gloves at a cute shop in St Pete (Speckled Red). If you’re looking for cool vintage stuff, check them out. So, I spent this afternoon sewing the lights onto the gloves. There was a lot of 3D design involved. We were really fortunate with the gloves because they have four seams on each finger. This makes it really easy to keep the various traces of conductive thread from touching each other. We needed four traces per finger, so this is a perfect match for our needs.

After a day’s work, we have our first cluster of lights sewn into our first glove. Since we’re both scientists, we’re testing small combinations of components to make sure our assumptions are on target before we proceed into the next phase. Now that most of the hard work is done and our first light cluster is in place, the next step is to attach the LilyPad, battery, and accelerometer sensor. That will give us our first opportunity to see how the glove behaves, using our best guess first draft firmware.

That’s coming up in Part 2. Stay tuned!

LED Cluster Sewn Into Black Glove

A Halloween Costume Worthy of Song

I don’t often celebrate Halloween to the extent I’d prefer. Inevitably, every year the event is suddenly a week away, and I have occasion to run around like a maniac, seeking a creative solution to my lameness. This year, I am planning ahead… by a week. But! This is what 2-day shipping is for. And without further delay, I present to you my plan for costume excellence:

This evening, I purchased some awesome hardware, called a LilyPad Arduino (http://lilypadarduino.org). It’s basically a flexible circuit that can be woven into any textile product using conductive thread. It has a USB adapter that allows me to program the system from my laptop. Simply plug in, download the firmware, unplug, and go. So, what exactly are we building?

Real-time interactive motion-sensitive performance art

Using embedded wearable electronics, we combine the computing power of a microcontroller with data from an accelerometer to control the intensity of an array of red, blue, green, and white LEDs woven into the fabric. In fact, all this is sewn right into the leather. We specifically chose to use gloves for this project because the hands are often the most expressive part of the body. The position of the arms dictates the direction of gravity measured by a sensor in the wrist. This signal is carried through stainless steel thread up the back of the hand into the LilyPad, where it is used to control the timing of signals out to the LED arrays for each color. When standing with arms down by your sides, the color is blue. With arms straight out, it’s green. With arms up, it’s red.

This motion-sensitive color presentation is wonderful on its own. When combined with dance, it takes on a new dimension, especially at night. The bright color against the dark makes for an ethereal experience. But that’s not far enough. We wanted to give some extra depth and richness to the experience, some way for the dancer to control the lights, either through movement or some manual interface. So, we added interactivity to the fingers. When pressing the thumb and index finger tips together, the LEDs flash slowly. The middle finger and thumb yield a medium frequency flash. The ring finger and thumb produce a high frequency flash.

With this combination of movement and touch, the dancer conjures a very specific visual experience, blending motion, light, and song. Observant readers will note I have not described a costume for myself. No, this costume is intended for my girlfriend. I will most likely go as Zombie Steve Jobs and watch her dance. She is, after all, a ninja dancer. *smoke bomb*