electrostatic

28 Articles

An exploded view of an electrostatic motor from manufacturer C-Motive. There is a silvery cylinder on the left, two half silver and half golden disks on either side and two thinner gold disks in the center. A square mountin plate is on the right hand side next to one of the silver/gold disks.

Electrostatic Motors Are Making A Comeback

October 29, 2024 by 21 Comments

Electrostatic motors are now common in MEMS applications, but researchers at the University of Wisconsin and spinoff C-Motive Technologies have brought macroscale electrostatic motors back. [via MSN/WSJ]

While the first real application of an electric motor was Ben Franklin’s electrostatically-driven turkey rotisserie, electromagnetic type motors largely supplanted the technology due to the types of materials available to engineers of the time. Newer dielectric fluids and power electronics now allow electrostatic motors to be better at some applications than their electromagnetic peers.

The main advantage of electrostatic motors is their reduced critical materials use. In particular, electrostatic motors don’t require copper windings or any rare earth magnets which are getting more expensive as demand grows for electrically-powered machines. C-Motive is initially targeting direct drive industrial applications, and the “voltage driven nature of an electrostatic machine” means they require less cooling than an electromagnetic motor. They also don’t use much if any power when stalled.

Would you like a refresher on how to make static electricity or a deeper dive on how these motors work?

Static Electricity And The Machines That Make It

September 30, 2024 by 20 Comments

Static electricity often just seems like an everyday annoyance when a wool sweater crackles as you pull it off, or when a doorknob delivers an unexpected zap. Regardless, the phenomenon is much more fascinating and complex than these simple examples suggest. In fact, static electricity is direct observable evidence of the actions of subatomic particles and the charges they carry.

While zaps from a fuzzy carpet or playground slide are funny, humanity has learned how to harness this naturally occurring force in far more deliberate and intriguing ways. In this article, we’ll dive into some of the most iconic machines that generate static electricity and explore how they work.

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Reprogrammable Transistors

March 26, 2024 by 21 Comments

Not every computer can make use of a disk drive when it needs to store persistent data. Embedded systems especially have pushed the development of a series of erasable programmable read-only memories (EPROMs) because of their need for speed and reliability. But erasing memory and writing it over again, whether it’s an EPROM, an EEPROM, an FPGA, or some other type of configurable solid-state memory is just scratching the surface of what it might be possible to get integrated circuits and their transistors to do. This team has created a transistor that itself is programmable.

Rather than doping the semiconductor material with impurities to create the electrical characteristics needed for the transistor, the team from TU Wien in Vienna has developed a way to “electrostatically dope” the semiconductor, using electric fields instead of physical impurities to achieve the performance needed in the material. A second gate, called the program gate, can be used to reconfigure the electric fields within the transistor, changing its properties on the fly. This still requires some electrical control, though, so the team doesn’t expect their new invention to outright replace all transistors in the future, and they also note that it’s unlikely that these could be made as small as existing transistors due to the extra complexity.

While the article from IEEE lists some potential applications for this technology in the broad sense, we’d like to see what these transistors are actually capable of doing on a more specific level. It seems like these types of circuits could improve efficiency, as fewer transistors might be needed for a wider variety of tasks, and that there are certainly some enhanced security features these could provide as well. For a refresher on the operation of an everyday transistor, though, take a look at this guide to the field-effect transistor.

Giving Solar Power’s Mortal Enemies A Dusting Without Wasting Water

August 16, 2023 by 28 Comments

A prerequisite for photovoltaic (PV) and concentrated solar power (CSP) technologies to work efficiently is as direct an exposure to the electromagnetic radiation from the sun as possible. Since dust and similar particulates are excellent at blocking the parts of the EM spectrum that determine their efficiency, keeping the panels and mirrors free from the build-up of dust, lichen, bird droppings and other perks of planetary life is a daily task for solar farm operators. Generally cleaning the panels and mirrors involves having trucks drive around with a large water tank to pressure wash the dirt off, but the use of so much water is problematic in many regions.

Keeping PV panels clean is also a consideration on other planets than Earth. So far multiple Mars rovers and landers have found their demise at the hands of Martian dust after a layer covered their PV panels, and Moon dust (lunar regolith) is little better. Despite repeated suggestions by the peanut gallery to install wipers, blowers or similar dust removal techniques, keeping particulates from sticking to a surface is not as easy an engineering challenge as it may seem, even before considering details such as the scaling issues between a singular robot on Mars versus millions of panels and mirrors on Earth.

There has been research into the use of the electrostatic effect to repel dust, but is there a method that can keep both solar-powered robots on Mars and solar farms on Earth clean and sparkling, rather than soiled and dark?

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ElectriPop Turns Cut Mylar Into Custom 3D Structures

May 6, 2022 by 14 Comments

Mylar has a lot of useful properties, and as such as see it pop up pretty often, not just in DIY projects but in our day-to-day lives. But until today, we’ve never seen a piece of Mylar jump up and try to get our attention. But that’s precisely the promise offered by ElectriPop, a fascinating project from Carnegie Mellon University’s Future Interfaces Group.

The core principle at work here is fairly simple. When electrostatically charged, a strip of Mylar can be made to lift up vertically into the air. Cut that strip down the center, and the two sides will repel each other and produce a “Y” shape. By expanding on that concept with enough carefully placed cuts, it’s possible to create surprisingly complex three dimensional shapes that pop up once a charge is applied. A certain degree of motion can even be introduced by adjusting the input power. The video after the break offers several examples of this principle in action: such as a 3D flower that either stands up tall or wilts in relation to an external source of data, or an avatar that flails its arms wildly to get the user’s attention.

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Simple Tip Helps With Powder Coating Perfection On Difficult Parts

July 24, 2021 by 8 Comments

To say that that the commercially available garden path lights commonly available at dollar stores are cheap is a vast overstatement of their true worthlessness. These solar-powered lights are so cheaply built that there’s almost no point in buying them, a fact that led [Mark Presling] down a fabrication rabbit hole that ends with some great tips on powder coating parts with difficult geometries.

Powder coating might seem a bit overkill for something as mundane as garden lights, but [Mark] has a point — if you buy something and it fails after a few weeks in the sun, you might as well build it right yourself. And a proper finish is a big part of not only getting the right look, but to making these totally un-Tardis-like light fixtures last in the weather. The video series below covers the entire design and build process, which ended up having an aluminum grille with some deep grooves. Such features prove hard to reach with powder coating, where the tiny particles of the coating are attracted to the workpiece thanks to a high potential difference between them. After coating, the part is heated to melt the particles and form a tough, beautiful finish.

But for grooves and other high-aspect-ratio features, the particles tend to avoid collecting in the nooks and crannies, leading to an uneven finish. [Mark]’s solution was to turn to “hot flocking”, where the part is heated before applying uncharged coating to the deep features. This gets the corners and grooves well coated before the rest of the coating is applied in the standard way, leading to a much better finish.

We love [Presser]’s attention to detail on this build, as well as the excellent fabrication tips and tricks sprinkled throughout the series. You might want to check out some of his other builds, like this professional-looking spot welder.

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Hackaday Links: November 22, 2020

November 22, 2020 by 6 Comments

Remember DSRC? If the initialism doesn’t ring a bell, don’t worry — Dedicated Short-Range Communications, a radio service intended to let cars in traffic talk to each other, never really caught on. Back in 1999, when the Federal Communications Commission set aside 75 MHz of spectrum in the 5.9-GHz band, it probably seemed like a good idea — after all, the flying cars of the future would surely need a way to communicate with each other. Only about 15,000 vehicles in the US have DSRC, and so the FCC decided to snatch back the whole 75-MHz slice and reallocate it. The lower 45 MHz will be tacked onto the existing unlicensed 5.8-GHz band where WiFi now lives, providing interesting opportunities in wireless networking. Fans of chatty cars need not fret, though — the upper 30 MHz block is being reallocated to a different Intelligent Transportation System Service called C-V2X, for Cellular Vehicle to Everything, which by its name alone is far cooler and therefore more likely to succeed.

NASA keeps dropping cool teasers of the Mars 2020 mission as the package containing the Perseverance rover hurtles across space on its way to a February rendezvous with the Red Planet. The latest: you can listen to the faint sounds the rover is making as it gets ready for its date with destiny. While we’ve heard sounds from Mars before — the InSight lander used its seismometer to record the Martian wind — Perseverance is the first Mars rover equipped with actual microphones. It’s pretty neat to hear the faint whirring of the rover’s thermal management system pump doing its thing in interplanetary space, and even cooler to think that we’ll soon hear what it sounds like to land on Mars.

Speaking of space, back at the beginning of 2020 — you know, a couple of million years ago — we kicked off the Hack Chat series by talking with Alberto Caballero about his “Habitable Exoplanets” project, a crowd-sourced search for “Earth 2.0”. We found it fascinating that amateur astronomers using off-the-shelf gear could detect the subtle signs of planets orbiting stars half a galaxy away. We’ve kept in touch with Alberto since then, and he recently tipped us off to his new SETI Project. Following the citizen-science model of the Habitable Exoplanets project, Alberto is looking to recruit amateur radio astronomers willing to turn their antennas in the direction of stars similar to the Sun, where it just might be possible for intelligent life to have formed. Check out the PDF summary of the project which includes the modest technical requirements for getting in on the SETI action.

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