Finger Bend Is A Textile Flex Sensor You Can Sew At Home

So often, we use control devices for electronics that involve our fingers directly grasping, touching, or moving another object or surface. It’s less common for us to use interfaces that detect the motion of our bodies directly. Flex sensors are one way to do that, and it’s exactly what [WillpowerStudios] aims to do with Finger Bend.

The construction of the sensor is simple, using piezoresistive fabric which changes its resistance when deformed. By sewing this into a sheath that can be placed on the finger, and wiring it up with conductive threads, it can be used to detect the flexion of the wearer’s digits by sampling the resistance with an analog to digital converter on any garden variety microcontroller. Expanding the technique to a full hand is as simple as creating a Finger Bend per digit and wiring up each one to its own ADC channel. If you want to get really fancy, you could even scan through them at speed with a multiplexer.

It’s similar to the technology used in Nintendo’s infamous Power Glove, and while it’s never caught on in the mainstream, it may have applications yet. Video after the break

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3D Printable Cloth Takes Advantage Of Defects

Normally, a 3D printer that under extrudes is a bad thing. However, MIT has figured out a way to deliberately mix full extrusions with under extruded layers to print structures that behave more like cloth than normal 3D printed items. The mesh-like structure apparently doesn’t require any modification to a normal 3D printer, just different software to create special code sequences to create the material.

Called DefeXtiles, [Jack Forman] is producing sheets and complex structures that appear woven. The process is known as “blob-stretch” because of the way the plastic makes blobs connected by fine filaments of plastic.

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Art Piece Builds Up Images With Dots On Thread

Hackers being as a rule practical people, we sometimes get a little guff when we run a story on an art installation, on the grounds of not being sufficiently hacky. We understand that, but sometimes the way an artist weaves technology into their pieces is just too cool to pass us, as with this thread-printing art piece entitled On Framing Textile Ambiguities.

We’ll leave criticism of the artistic statement that [Nathalie Gebert]’s installation makes to others more qualified, and instead concentrate on its technical aspects. The piece has four frames made mainly from brass rods. Three of the frames have vertical rods that are connected to stepper motors and around which is wrapped a single thread. The thread weaves back and forth over the rods on one frame, forming a flat surface that constantly changes as the rods rotate, before heading off to do the same on the others. The fourth frame has a platen that the thread passes over with a pen positioned right above it. As the thread pauses in its endless loop, the pen clicks down onto it, making a dot of color. The dots then wend their way through the frame, occasionally making patterns that are just shy of recognizable before morphing into something new. The video below shows it better than it can be easily described.

Love it or hate it, you’ve got to admit that it has some interesting potential as a display. And it sort of reminds us of this thread-art polar robot, although this one has the advantage of being far simpler.

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You Are Your Own Tactile Feedback

[Maurin Donneaud] has clearly put a lot of work into making a large flexible touch sensitive cloth, providing a clean and intuitive interface, and putting it out there for anyone to integrate into their own project.. This pressure sensing fabric is touted as an electronic musical interface, but if you only think about controlling music, you are limiting yourself. You could teach AI to land a ‘copter more evenly, detect sparring/larping strikes in armor, protect athletes by integrating it into padding, or measure tension points in your golf swing, just to name a few in sixty seconds’ writers brainstorming. This homemade e-textile measures three dimensions, and you can build it yourself with conductive thread, conductive fabric, and piezoresistive fabric. If you were intimidated by the idea before, there is no longer a reason to hold back.

The idea is not new and we have seen some neat iterations but this one conjures ideas a mile (kilometer) a minute. Watching the wireframe interface reminds us of black-hole simulations in space-time, but these ones are much more terrestrial and responding in real-time. Most importantly they show consistent results when stacks of coins are placed across the surface. Like most others out there, this is a sandwich where the slices of bread are ordinary fabric and piezoresistive material and the cold cuts are conductive strips arranged in a grid. [Maurin] designed a custom PCB which makes a handy adapter between a Teensy and houses a resistor network to know which grid line is getting pressed.

If you don’t need flexible touch surfaces, we can help you there too.

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Three-Conductor Pivot For E-Textiles Is Better Than Wires

Pivots for e-textiles can seem like a trivial problem. After all, wires and fabrics bend and flex just fine. However, things that are worn on a body can have trickier needs. Snap connectors are the usual way to get both an electrical connection and a pivot point, but they provide only a single conductor. When [KOBAKANT] had a need for a pivoting connection with three electrical conductors, they came up with a design that did exactly that by using a flexible circuit board integrated to a single button snap.

This interesting design is part of a solution to a specific requirement, which is to accurately measure hand movements. The photo shows two strips connected together, which pivot as one. The metal disk near the center is a magnet, and underneath it is a Hall effect sensor. When the wrist bends, the magnet is moved nearer or further from the sensor and the unit flexes and pivots smoothly in response. The brief videos embedded below make it clear how the whole thing works.

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Mechanisms: Hook And Loop Fasteners

As a species, we’ve done a pretty good job at inventing some useful devices. But as clever as we think we are, given sufficient time, natural selection will beat us at our game at almost every turn. So it makes sense that many of our best inventions are inspired by nature and the myriad ways life finds to get DNA from one generation to the next.

Hook and loop fasteners are one such design cribbed from nature, and the story behind this useful mechanism is a perfect example that a prepared mind, good observation skills, and a heck of a lot of perseverance are what it takes to bring one of Mother Nature’s designs to market.

Editor’s Note: As some predicted in the comments section, we were contacted by representatives of Velcro Companies and asked to change all mentions in this article to either VELCRO® Brand Fastener or to use the generic “Hook and Loop” term. If it seems weird that we’re calling this hook and loop, now you know why.

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Stephanie Kwolek: Saving Lives With Kevlar

Almost a really bad day in the woods.

Like most accidents, it happened in an instant that seemed to last an eternity. I had been felling trees for firewood all afternoon, and in the waning light of a cold November day, I was getting ready to call it quits. There was one tiny little white pine sapling left that I wanted to clear, no thicker than my arm. I walked over with my Stihl MS-290, with a brand new, razor sharp chain. I didn’t take this sapling seriously — my first mistake — and cut right through it rather than notching it. The tree fell safely, and I stood up with both hands on the saw. Somehow I lost my footing, swiveled, and struck my left knee hard with the still-running chainsaw. It kicked my knee back so hard that it knocked me to the ground.

In another world, that would likely have a been a fatal injury — I was alone, far from the house, and I would have had mere minutes to improvise a tourniquet before bleeding out. But as fate would have it, I was protected by my chainsaw chaps, full of long strands of the synthetic fiber Kevlar.

The chain ripped open the chaps, pulled the ultrastrong fibers out, and instantly jammed the saw. I walked away feeling very stupid, very lucky, and with not a scratch on me. Although I didn’t realize it at the time,  I owed my life to Stephanie Kwolek.

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