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The IoT’s E-Waste Problem Isn’t Inevitable

Decisions that manufacturers make now could mean much less e-waste in a decade

2 min read
Illustration of a smiling person with a watch on their wrist and frowning watches on a necklace around their neck.
Illustration: Jude Buffum

In my office closet, I have a box full of perfectly good smart-home gadgets that are broken only because the companies that built them stopped updating their software. I can't bear to toss them in a landfill, but I don't really know how to recycle them. I'm not alone: Electronic waste, or e-waste, has become much more common.

The adoption of Project Connected Home Over IP (CHIP) standards by Amazon, Apple, Google, and the Zigbee Alliance will make smart homes more accessible to more people. But the smart devices these people bring into their homes will also eventually end up on the junk heap.

Perhaps surprisingly, we still don't have a clear answer as to what we should do when a product's software doesn't outlive its hardware, or when its electronics don't outlast the housing. Companies are building devices that used to last decades—such as thermostats, fridges, or even lights—with five- to seven-year life-spans.

When e-waste became a hot topic in the computing world, computer makers such as Dell and HP worked with recycling centers to better recycle their electronics. You might argue that those programs didn't do enough, because e-waste is still a growing problem. In 2019 alone, the world generated 53.6 million metric tons of e-waste, according to a report from the Global E-waste Monitor. And the amount is rising: According to the same report, each year we produce 2.5 million metric tons more e-waste than the year before.

This is an obviously unsustainable amount of waste. While recycling programs might not be enough to solve the problem, I'd still like to see the makers of connected devices partner up with recycling centers to take back devices when they are at the end of their lives. The solution could be as simple as, say, Amazon adding a screen to the app for a smart device that offers the address of a local recycling partner whenever someone chooses to decommission that device.

The idea is not unprecedented for smart devices. The manufacturer of the Tile tracking device has an agreement with a startup called Emplacement that offers recycling information when the battery on one of Tile's trackers dies and the device is useless. Another example is GE Appliances, which hauls away old appliances when people buy new ones, even as added software potentially shortens their years of usefulness.

Companies can also make the recycling process easier by designing products differently. For example, they should rely less on glues that make it hard to salvage recyclable metals from within electronic components and use smaller circuit boards with minimal components. Companies should also design their connected products so that they physically work in some fashion even if the software and app are defunct. In other words, no one should design a connected product that works only with an app, because doing so is all but forcing its obsolescence in just a few years. If the device still works, however, people might be able to pass it along for reuse even if some of the fancier features aren't operational.

Connected devices won't be in every home in the future, but they will become more common, and more people will come to rely on the features they offer. Which means we're set for an explosion of new electronic waste in the next five to ten years as these devices reach the end of their life-spans. How we handle that waste—and how much of it we have to deal with—depends on the decisions companies make now.

This article appears in the January 2021 print issue as “E-Waste Isn't Inevitable."

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The Inner Beauty of Basic Electronics

Open Circuits showcases the surprising complexity of passive components

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

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.

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