“Naked Truths” About Wearable Electronics

Panel at SXSW Interactive bares all (sort of) in search of the next big thing in wearables

3 min read
“Naked Truths” About Wearable Electronics
Photo: Glenn Zorpette

So, maybe you’ve bought a Nike+ Fuelband or a Jawbone UP band. Maybe it’s still on your wrist, and you check its data compulsively. But maybe it’s in a drawer, with your clunky smartwatch, your portable HD radio, and your Microsoft Zune.

Or maybe you are an early adherent of Google Glass, stoically enduring the discomfort and occasional aggression of friends, relatives, passersby, and drunk, enraged bar patrons. On the other hand, perhaps, like app developer Q Manning, you’ve concluded sadly that Google Glass is “great for texting and that’s about it.”

“I don’t think wearable technology has found its niche,” Manning added during a panel session Monday at the SXSW Interactive conference. “We all know we want it, but we don’t know what we want it to do yet. We’re all waiting for someone to solve that problem, but, unfortunately, Steve [Jobs] is gone.”

Manning’s co-panelists certainly had a few ideas, though, and one of them was vividly demonstrated by a pair of statuesque models who took the stage in technologically advanced and yet attractive underwear, prompting a blizzard of camera flashes. The demonstration came as close as could be reasonably expected to fulfilling the promise of the session’s title: “Tech Off Your Clothes: Naked Truths Of Wearables.”

The underwear were prototypes developed in a project called “Fundawear,” explained panelist Jay Morgan of the marketing firm Havas Worldwide. Havas had been hired by the UK-based manufacturer Durex, which was eager to associate its brand more with innovation. Though it offers an extensive line of personal massagers, for example, Durex is generally recognized only as a maker of condoms.

Havas was charged with coming up with a splashy innovation for Durex, and their brainstorming soon centered on the question, “can we do something for [lovers] when they are not together? Can you actually touch someone over the Internet?”

This proposal led to what can only be called a milestone in human civilization: the first ever electrically-engineered underwear. Fundawear was designed by another of the SXSW panelists, Billie Whitehouse, whose firm is called Wearable Experiments. The prototype Fundawear samples are close-fitting black undergarments equipped with tiny haptic electromagnetic vibrators, which produce a momentary sensation much like piezoelectric-based units used to create the quick vibration in a smartphone when a key is touched. The units are strategically installed in the garments—in the female version, in both brassiere and panties—to make contact with sensitive regions of the body. When the wearer’s partner touches his or her smartphone—the sensitive regions are helpfully indicated on a template on the phone’s screen—the wearer feels a gentle frisson, or even a light stroke, depending on whether the partner has touched or swiped the screen.

The engineering challenges were nontrivial, Morgan explained. First, they wanted to create the sensation of a lover’s gentle touch, and finding a technology that could reliably and safely produce that feeling—and be laundered—wasn’t easy. “There was some great work in electroactive polymers at the University of Auckland,” Morgan explained. “We contacted them and they said, ‘where are you going to stick this stuff?’ And we said, ‘down in your pants.’ They said, ‘Oh, that’s probably not a good idea,’” noting that the polymers operate at 4500 volts.

Another challenge was making instantaneous contact, no matter how far apart the partners were. An app pairs the wearer’s smartphone to his or her garment, using WiFi (Bluetooth would be used if Fundawear is put into production, Morgan said). But the users’ phones have to communicate with each other securely and instantaneously. The design team solved that one by using Amazon Web Services, a cloud scheme, to convey the data between phones. Each partner has a secret key to assure security, Morgan added.

Eugenia and Stephen, the models who wore Fundawear at the SXSW session, were delighted with it. “It’s a very light vibration, like a touch,” said Eugenia. “It depends on how you touch,” she said. “If you slide, it’s like a stroke.” The two did not know each other prior to the SXSW assignment, and they each controlled their own undergarment, Eugenia said. “We didn’t want to be too intimate in this situation,” she explained. (Stephen didn’t have a comment.)

Morgan said executives with Durex’s Global Product Development Team are studying the feasibility of putting the wearables into production. He said a decision could be announced in the next several months.

Wearable Experiments’ Whitehouse demonstrated another possible direction for wearables at the session. She was wearing her Navigate Jacket, which pairs to a smartphone app and gives gentle and appropriately timed taps on the left or right shoulder to guide the wearer to a destination.

Asked about the future of the jacket, Whitehouse replied, possibly with tongue slightly in cheek, “The future of this jacket, for me, is inductive-charging coathangers.”

Later in the session, when asked about what people, particularly older people, really want in wearable electronics, she said: “My mother, in particular, just wants a device that repels all other technology. That doesn’t let people track her, or contact her.”

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The Inner Beauty of Basic Electronics

Open Circuits showcases the surprising complexity of passive components

5 min read
A photo of a high-stability film resistor with the letters "MIS" in yellow.
All photos by Eric Schlaepfer & Windell H. Oskay

Eric Schlaepfer was trying to fix a broken piece of test equipment when he came across the cause of the problem—a troubled tantalum capacitor. The component had somehow shorted out, and he wanted to know why. So he polished it down for a look inside. He never found the source of the short, but he and his collaborator, Windell H. Oskay, discovered something even better: a breathtaking hidden world inside electronics. What followed were hours and hours of polishing, cleaning, and photography that resulted in Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022), an excerpt of which follows. As the authors write, everything about these components is deliberately designed to meet specific technical needs, but that design leads to “accidental beauty: the emergent aesthetics of things you were never expected to see.”

From a book that spans the wide world of electronics, what we at IEEE Spectrum found surprisingly compelling were the insides of things we don’t spend much time thinking about, passive components. Transistors, LEDs, and other semiconductors may be where the action is, but the simple physics of resistors, capacitors, and inductors have their own sort of splendor.

High-Stability Film Resistor

A photo of a high-stability film resistor with the letters "MIS" in yellow.

All photos by Eric Schlaepfer & Windell H. Oskay

This high-stability film resistor, about 4 millimeters in diameter, is made in much the same way as its inexpensive carbon-film cousin, but with exacting precision. A ceramic rod is coated with a fine layer of resistive film (thin metal, metal oxide, or carbon) and then a perfectly uniform helical groove is machined into the film.

Instead of coating the resistor with an epoxy, it’s hermetically sealed in a lustrous little glass envelope. This makes the resistor more robust, ideal for specialized cases such as precision reference instrumentation, where long-term stability of the resistor is critical. The glass envelope provides better isolation against moisture and other environmental changes than standard coatings like epoxy.

15-Turn Trimmer Potentiometer

A photo of a blue chip
A photo of a blue chip on a circuit board.

It takes 15 rotations of an adjustment screw to move a 15-turn trimmer potentiometer from one end of its resistive range to the other. Circuits that need to be adjusted with fine resolution control use this type of trimmer pot instead of the single-turn variety.

The resistive element in this trimmer is a strip of cermet—a composite of ceramic and metal—silk-screened on a white ceramic substrate. Screen-printed metal links each end of the strip to the connecting wires. It’s a flattened, linear version of the horseshoe-shaped resistive element in single-turn trimmers.

Turning the adjustment screw moves a plastic slider along a track. The wiper is a spring finger, a spring-loaded metal contact, attached to the slider. It makes contact between a metal strip and the selected point on the strip of resistive film.

Ceramic Disc Capacitor

A cutaway of a Ceramic Disc Capacitor
A photo of a Ceramic Disc Capacitor

Capacitors are fundamental electronic components that store energy in the form of static electricity. They’re used in countless ways, including for bulk energy storage, to smooth out electronic signals, and as computer memory cells. The simplest capacitor consists of two parallel metal plates with a gap between them, but capacitors can take many forms so long as there are two conductive surfaces, called electrodes, separated by an insulator.

A ceramic disc capacitor is a low-cost capacitor that is frequently found in appliances and toys. Its insulator is a ceramic disc, and its two parallel plates are extremely thin metal coatings that are evaporated or sputtered onto the disc’s outer surfaces. Connecting wires are attached using solder, and the whole assembly is dipped into a porous coating material that dries hard and protects the capacitor from damage.

Film Capacitor

An image of a cut away of a capacitor
A photo of a green capacitor.

Film capacitors are frequently found in high-quality audio equipment, such as headphone amplifiers, record players, graphic equalizers, and radio tuners. Their key feature is that the dielectric material is a plastic film, such as polyester or polypropylene.

The metal electrodes of this film capacitor are vacuum-deposited on the surfaces of long strips of plastic film. After the leads are attached, the films are rolled up and dipped into an epoxy that binds the assembly together. Then the completed assembly is dipped in a tough outer coating and marked with its value.

Other types of film capacitors are made by stacking flat layers of metallized plastic film, rather than rolling up layers of film.

Dipped Tantalum Capacitor

A photo of a cutaway of a Dipped Tantalum Capacitor

At the core of this capacitor is a porous pellet of tantalum metal. The pellet is made from tantalum powder and sintered, or compressed at a high temperature, into a dense, spongelike solid.

Just like a kitchen sponge, the resulting pellet has a high surface area per unit volume. The pellet is then anodized, creating an insulating oxide layer with an equally high surface area. This process packs a lot of capacitance into a compact device, using spongelike geometry rather than the stacked or rolled layers that most other capacitors use.

The device’s positive terminal, or anode, is connected directly to the tantalum metal. The negative terminal, or cathode, is formed by a thin layer of conductive manganese dioxide coating the pellet.

Axial Inductor

An image of a cutaway of a Axial Inductor
A photo of a collection of cut wires

Inductors are fundamental electronic components that store energy in the form of a magnetic field. They’re used, for example, in some types of power supplies to convert between voltages by alternately storing and releasing energy. This energy-efficient design helps maximize the battery life of cellphones and other portable electronics.

Inductors typically consist of a coil of insulated wire wrapped around a core of magnetic material like iron or ferrite, a ceramic filled with iron oxide. Current flowing around the core produces a magnetic field that acts as a sort of flywheel for current, smoothing out changes in the current as it flows through the inductor.

This axial inductor has a number of turns of varnished copper wire wrapped around a ferrite form and soldered to copper leads on its two ends. It has several layers of protection: a clear varnish over the windings, a light-green coating around the solder joints, and a striking green outer coating to protect the whole component and provide a surface for the colorful stripes that indicate its inductance value.

Power Supply Transformer

A photo of a collection of cut wires
A photo of a yellow element on a circuit board.

This transformer has multiple sets of windings and is used in a power supply to create multiple output AC voltages from a single AC input such as a wall outlet.

The small wires nearer the center are “high impedance” turns of magnet wire. These windings carry a higher voltage but a lower current. They’re protected by several layers of tape, a copper-foil electrostatic shield, and more tape.

The outer “low impedance” windings are made with thicker insulated wire and fewer turns. They handle a lower voltage but a higher current.

All of the windings are wrapped around a black plastic bobbin. Two pieces of ferrite ceramic are bonded together to form the magnetic core at the heart of the transformer.

This article appears in the February 2023 print issue.