Electronics

MIT engineers 3D print the electromagnets at the heart of many electronics

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The printed solenoids could enable electronics that cost less and are easier to manufacture — on Earth or in space.

On top of a quarter sits a disc-like device chopped in half to show the interior: purple plastic is on outside, eight stacks of coiled copper-colored rods; and in the middle is a black substance.

MIT researchers modified a multi-material 3D printer so it could produce three-dimensional solenoids in one step by layering ultrathin coils of three different materials. It prints a U.S. quarter-sized solenoid as a spiral by layering material around the soft magnetic core, with thicker conductive layers separated by thin insulating layers.

A rectangular part of a 3D printer is on the table. It is made of plastic 3D-printed parts, metal pieces, and has wires extruding. It is labeled “3D-printed pellet funnel; 3D-printed extruder case; E3D tool pick-up/drop-off plate; E3D tool docking port; and Mahor v4 pellet extruder.”

The researchers modified a multimaterial 3D printer so it could print compact, magnetic-cored solenoids in one step. This eliminates defects that might be introduced during post-assembly processes.

On left is a pile of black pebbles labeled, “FeSiAl Nylon pellets.” In middle is a metal rod labeled “extruded filament.” And on right is a tiny metal bit next to a coiled device, and is labeled “extruded core and air-cored solenoid.”

Solenoids are produced by precisely layering three different materials — a dielectric material that serves as an insulator, a conductive material that forms the electric coil, and a soft magnetic material that makes up the core. The soft magnetic material the researchers used, which is in the form of pellets, achieves higher performance than filament-based materials.

Imagine being able to build an entire dialysis machine using nothing more than a 3D printer.

This could not only reduce costs and eliminate manufacturing waste, but since this machine could be produced outside a factory, people with limited resources or those who live in remote areas may be able to access this medical device more easily.

While multiple hurdles must be overcome to develop electronic devices that are entirely 3D printed, a team at MIT has taken an important step in this direction by demonstrating fully 3D-printed, three-dimensional solenoids.

Solenoids, electromagnets formed by a coil of wire wrapped around a magnetic core, are a fundamental building block of many electronics, from dialysis machines and respirators to washing machines and dishwashers.

The researchers modified a multimaterial 3D printer so it could print compact, magnetic-cored solenoids in one step. This eliminates defects that might be introduced during post-assembly processes.

This customized printer, which could utilize higher-performing materials than typical commercial printers, enabled the researchers to produce solenoids that could withstand twice as much electric current and generate a magnetic field that was three times larger than other 3D-printed devices.

In addition to making electronics cheaper on Earth, this printing hardware could be particularly useful in space exploration. For example, instead of shipping replacement electronic parts to a base on Mars, which could take years and cost millions of dollars, one could send a signal containing files for the 3D printer, says Luis Fernando Velásquez-García, a principal research scientist in MIT’s Microsystems Technology Laboratories (MTL).

“There is no reason to make capable hardware in only a few centers of manufacturing when the need is global. Instead of trying to ship hardware all over the world, can we empower people in distant places to make it themselves? Additive manufacturing can play a tremendous role in terms of democratizing these technologies,” adds Velásquez-García, the senior author of a new paper on the 3D printed solenoids that appears in the journal Virtual and Physical Prototyping.

He is joined on the paper by lead author Jorge Cañada, an electrical engineering and computer science graduate student; and Hyeonseok Kim, a mechanical engineering graduate student.

Additive advantages

A solenoid generates a magnetic field when an electrical current is passed through it. When someone rings a doorbell, for instance, electric current flows through a solenoid, which generates a magnetic field that moves an iron rod so it strikes a chime.

Integrating solenoids onto electrical circuits manufactured in a clean room poses significant challenges, as they have very different form factors and are made using incompatible processes that require post assembly. Consequently, researchers have investigated making solenoids utilizing many of the same processes that make semiconductor chips. But these techniques limit the size and shape of solenoids, which hampers performance.

With additive manufacturing, one can produce devices that are practically any size and shape. However, this presents its own challenges, since making a solenoid involves coiling thin layers made from multiple materials that may not all be compatible with one machine.

To overcome these challenges, the researchers needed to modify a commercial extrusion 3D printer.

Extrusion printing fabricates objects one layer at a time by squirting material through a nozzle. Typically, a printer uses one type of material feedstock, often spools of filament.

“Some people in the field look down on them because they are simple and don’t have a lot of bells and whistles, but extrusion is one of very few methods that allows you to do multimaterial, monolithic printing,” says Velásquez-García.

This is key, since the solenoids are produced by precisely layering three different materials — a dielectric material that serves as an insulator, a conductive material that forms the electric coil, and a soft magnetic material that makes up the core.

The team selected a printer with four nozzles — one dedicated to each material to prevent cross-contamination. They needed four extruders because they tried two soft magnetic materials, one based on a biodegradable thermoplastic and the other based on nylon.

Printing with pellets

They retrofitted the printer so one nozzle could extrude pellets, rather than filament. The soft magnetic nylon, which is made from a pliable polymer studded with metallic microparticles, is virtually impossible to produce as a filament. Yet this nylon material offers far better performance than filament-based alternatives.

Using the conductive material also posed challenges, since it would start melting and jam the nozzle. The researchers found that adding ventilation to cool the material prevented this. They also built a new spool holder for the conductive filament that was closer to the nozzle, reducing friction that could damage the thin strands.

Even with the team’s modifications, the customized hardware cost about $4,000, so this technique could be employed by others at a lower cost than other approaches, adds Velásquez-García.

The modified hardware prints a U.S. quarter-sized solenoid as a spiral by layering material around the soft magnetic core, with thicker conductive layers separated by thin insulating layers.

Precisely controlling the process is of paramount importance because each material prints at a different temperature. Depositing one on top of another at the wrong time might cause the materials to smear.

Because their machine could print with a more effective soft magnetic material, the solenoids achieved higher performance than other 3D-printed devices.

The printing method enabled them to build a three-dimensional device comprising eight layers, with coils of conductive and insulating material stacked around the core like a spiral staircase. Multiple layers increase the number of coils in the solenoid, which improves the amplification of the magnetic field.

Due to the added precision of the modified printer, they could make solenoids that were about 33 percent smaller than other 3D-printed versions. More coils in a smaller area also boosts amplification.

In the end, their solenoids could produce a magnetic field that was about three times larger than what other 3D-printed devices can achieve.

“We were not the first people to be able to make inductors that are 3D-printed, but we were the first ones to make them three-dimensional, and that greatly amplifies the kinds of values you can generate. And that translates into being able to satisfy a wider range of applications,” he says.

For instance, while these solenoids can’t generate as much magnetic field as those made with traditional fabrication techniques, they could be used as power convertors in small sensors or actuators in soft robots.

Moving forward, the researchers are looking to continue enhancing their performance.

For one, they could try using alternate materials that might have better properties. They are also exploring additional modifications that could more precisely control the temperature at which each material is deposited, reducing defects.

New graphene semiconductor could revolutionize electronics

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The supermaterial outperformed silicon and could lead to incredibly fast computers.

A person is holding a box with a graphene semiconductor chip in it.

The world’s first functional graphene semiconductor outperformed one made of silicon — suggesting that the supermaterial could be the future of computing.

The background: A material can be classified by how well it conducts electricity. If electrons flow easily through it, it’s a “conductor”; if they don’t, it’s an “insulator.” Between the two are “semiconductors,” materials that can conduct electricity well, but only under specific conditions.

That property has made semiconductors the backbone of computing — by making microchips from the semiconducting material silicon, we can easily control when electricity does or does not flow through them, giving us a way to “speak” to computers in their language of 1s and 0s.

A graphene semiconductor: We’re starting to reach the limits of what silicon can do in computer chips, though, and in the hunt for alternatives, a team led by Georgia Tech physics professor is looking closely at graphene, a super-strong two-dimensional form of carbon.

“We were motivated by the hope of introducing three special properties of graphene into electronics,” said de Heer. “It’s an extremely robust material, one that can handle very large currents, and [it] can do so without heating up and falling apart.”

The problem is that graphene isn’t a semiconductor — not naturally, anyway. 

“It’s like driving on a gravel road versus driving on a freeway.”WALTER DE HEER

What’s new? Through past research, de Heer’s team discovered how to grow graphene on wafers of silicon carbide, and through years of refinement, they figured out how to get that graphene to demonstrate semiconducting properties.

For their latest study, published in Nature, they demonstrated how they could “dope” their graphene semiconductor with atoms to create a transistor, one of the switches or gates that controls the flow of electricity in a chip.

“Our motivation for doing graphene electronics has been there for a long time, and the rest was just making it happen,” said de Heer. “We had to learn how to treat the material, how to make it better and better, and finally how to measure the properties. That took a very, very long time.” 

According to their testing, electrons flowed through the graphene semiconductor more easily than one made of silicon, which suggests the approach could lead to faster computers.

“It’s like driving on a gravel road versus driving on a freeway,” said de Heer. “It’s more efficient, it doesn’t heat up as much, and it allows for higher speeds so that the electrons can move faster.”

Looking ahead: The electronics industry isn’t going to drop silicon for graphene (or any other material) overnight, and performance isn’t the only consideration when they do make a change — cost, durability, ease of manufacturing, and more will all play a role.

Still, de Heer is confident that, when the next major shift in electronics does happen, graphene will be at the center of it.

“Graphene is the next step,” he said. “Who knows what the step’s going to be after that, but there’s a good chance that graphene can take over and be the paradigm for the next 50 years.”

Samsung unveils “Ballie” SPY MACHINE that rolls around your home spying on everything while controlling your electronic devices

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In a race with Amazon to the bottom, Samsung has unveiled a new spy machine robot called “Ballie” that rolls around people’s homes watching and listening to everything they do while controlling all their electronic devices.

First unveiled back in 2020, Ballie’s latest hypothetical design is roughly the size of a bowling ball on wheels – previously it was only about the size of a tennis ball. The spying device also now contains a built-in projector that can display a virtual work call, a yoga program, or whatever else the user wants projected on a wall or ceiling – the video below shows what Ballie looks like and what it does:

4. AI Robot companion called ‘Ballie’ by Samsung pic.twitter.com/dPV9dn9hsl

— Rowan Cheung (@rowancheung) January 9, 2024

(Related: Previously, Amazon’s Echo device was considered to be the ultimate spy machine to listen to and record everything users do and say.)

Does the world really need another in-home spying device?

At the recent CES 2024 event, Samsung showed off the Ballie in a demo, though attendees were not allowed any one-on-one time with the spherical robot device. In the demo, Ballie’s movements were “obviously tightly scripted and controlled,” to quote Engadget‘s Nathan Ingraham.

Ingraham says the demo “at the very least … gave us an idea of how the company envisions Ballie being used.” In other words, Ballie’s real-life use cases are still all hypothetical as the device is still under development.

An actor at CES 2024 asked Ballie to start a workout routine for him, which prompted the machine to project a workout video on the wall for immediate use, along with music to go along with it.

“Sure, you could just use your TV for that, but when one of the exercises called for laying down, Ballie shot the video to the ceiling so the actor could continue following along,” Ingraham explains.

In another demo example, Ballie displayed a visual representation of the air quality of a home to which it was connected via an air purifier. Ballie displayed not only particulate statistics but also a warning that the filter in the air purifier needed changing.

“The idea here is to show that Ballie can talk to all your smart home devices and display info from them, even if they don’t have a dedicated display,” Ingraham says.

Much like a smartphone, Ballie is also able to display a user’s calendar, place phone calls and even show video footage of, say, the inside of one’s “smart” Samsung refrigerator or the front stoop in the pathway of a “smart” doorbell.

“It’s cute, and it was fun to see Ballie confidently rolling around the floor of the demo area, but I can’t help but think that it’s solving exactly zero real world problems either,” Ingraham further notes.

According to Samsung, the first working Ballie devices will be on sale towards the end of the year, but not everyone, including Ingraham, is convinced it will actually materialize.

“I’m not fully convinced, as we’ve seen a lot of similar projects die in the wind, but I am definitely rooting for the little robot,” he writes.

Reports indicate that the latest iteration of Ballie presented at CES 2024 contains a spatial LiDAR sensor and a 1080p projector, the latter of which has two lenses and allows the robot to project movies, video calls and “greetings” on its surrounding surfaces.

A video shown during the device’s keynote depicted Ballie greeting a user who just returned home from work or an errand by projecting the word “Welcome” on the wall.

E-Cigarette Smoking Could be Banned at L.A. Restaurants, Beaches

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Thumbnail image for e_cigarette_Michael_Dorausch_Flickr_ok.JPG
Michael Dorausch/Flickr

Hold onto to your e-cigarettes while you can, people, because using them might soon be banned in the same places that prohibit lighting up regular smokes.

The L.A. City Council today will consider a new motion to be introduced by Councilman Mitch O’Farrell that would treat electronic devices the same way that cigarette smoking is regulated in town.

And means no puffing, electronic or otherwise, in or on:

-elevators
-supermarkets
–offices
-restaurants
-city beaches, or
-within 25 feet of playground equipment, bleachers, backstops, sports courts and fields, and picnic areas.

Yep. O’Farrell’s spokesman, Tony Arranaga, confirmed to the Weekly the gist of today’s proposal.

According to a statement put out by the offices of O’Farrell and the City Attorney:

The motion directs the City Attorney’s office to draft an ordinance to regulate the usage of electronic smoking devices where smoking is prohibited by law.

But wait, there’s more:

The council today will also weigh Councilman Paul Koretz‘s motion to raise the age limit on e-cigarette purchases to those 18 or older. As it stands, electronic tobacco retailing has no age limit for customers.

There have also been efforts on the state level to treat the battery-operated “vapes” (for nicotine vaporizers or atomizers) the same as regular cigs.

Proponents of e-cigarettes have been enjoying loopholes in the law, often smoking at bars and restaurants without reprisal. They argue that the water vapor emitted by the devices is not smoke and that it is not harmful.

However, some critics say that scientific testing has yet to catch up with the devices. The jury is still out about whether they are the source of second-hand smoke danger.

Wireless bio-absorbable circuits could kill bacteria.

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Remote-controlled, dissolvable electronic implants have been created that could help attack microbes, provide pain relief and stimulate bone growth.

The spread of bacteria resistant to antibiotics – popularly called superbugs – is threatening to put the clock back 100 years to the time when routine, minor surgery was life-threatening. Some medical experts are warning that otherwise straightforward operations could soon become deadly unless new ways to fend off these infections are found.

Bacteria often evolve clever ways of evading chemical assaults, but they will always struggle to resist the old-fashioned way of killing them: heating them up. It takes only a relatively mild warming to kill bugs without discomfort or harm to tissues. So imagine if little electric heaters could be implanted into wounds and powered wirelessly to fry bacteria during healing before dissolving harmlessly into body fluids once their job is done.

This is just one potential application of the bio-absorbable electronic circuits made by John Rogers of the University of Illinois at Urbana-Champaign and his co-workers. The idea itself is not new: Rogers and others have previously reported biodegradable flexible circuits and electronic devices that can be safely laid directly onto skin. But their success in making their circuits wireless could prove crucial to many potential applications, especially in medicine.

The hope is that radio waves can be used both for remote control of the circuits – to turn them on and off, say, and to provide the power to run them, so that there’s no need for implanted batteries. This kind of radio-frequency (RF) wireless technology is becoming ever more widespread, in food packaging, livestock labelling, tagging of goods in shops for security and in dustbins to monitor recycling, for example.

To make RF circuits, you need semiconductors and metals. Those don’t sound like the kinds of materials our bodies will dissolve, but Rogers and colleagues used layers of non-toxic substances so thin that they disintegrate in water or body fluids. For the metal parts, they used films of magnesium at least half as thin as the average human hair. Magnesium is not only harmless but in fact an essential nutrient: our bodies typically contain about 25g (0.9oz) of it already. For semiconductors, they used silicon membranes 300 nanometres (millionths of a millimetre) thick, which also dissolve in water. They used magnesium oxide as an insulating material when required.

Power scavenger

One of the simplest but most important components of an RF circuit is an antenna, which picks up the radio waves. Rogers and colleagues made these from long strips of magnesium foil deposited onto thin films of silk. Being non-toxic, biodegradable, strong and relatively cheap, silk makes the ideal base for such devices. These antennae, typically about four inches long, dissolve completely in water in about two hours. Although being buried beneath radio wave-absorbing body tissue would hamper performance, they should still receive enough signal for low power applications the researchers are considering.

The researchers have also made a variety of standard circuit components: capacitors, resistors, and crucially, diodes and transistors. Transistors are particularly complex structures, requiring delicately patterned films of a semiconductor like silicon doped with other elements and sandwiched with metal electrodes and insulating layers. Using silicon membranes, along with magnesium and its oxide, Rogers’ team made versions that dissolve within hours.

One of the first full circuits that they have made is an RF “power scavenger”, which can convert up to 15% of the radio waves it absorbs at a particular frequency into electrical power. Their prototype, measuring about 10cm (4in) by 4cm (1.6 in), can pick up enough power to run a small commercial light-emitting diode. The team can control the rate at which these devices dissolve by fine-tuning the molecular structure of the silk sheets on which they are laid down or between which they are sandwiched. This way, they can make devices that last for a week or two – about the length of time needed to ward off bacteria from a healing wound.

As well as deterring bacteria, Rogers says that implantable, bio-absorbable RF electronics could be used to stimulate nerves for pain relief, and to stimulate bone re-growth, a process long proven to work when electrodes are placed on the skin or directly on the bone. Conceivably they could also be used to precisely control drug release from implanted reservoirs.

Source: BBC