Rapid Charging Supercapacitors

September 16, 2020 by Bryan Cockfield 40 Comments

Battery technology is the talk of the town right now, as it’s the main bottleneck holding up progress on many facets of renewable energy. There are other technologies available for energy storage, though, and while they might seem like drop-in replacements for batteries they can have some peculiar behaviors. Supercapacitors, for example, have a completely different set of requirements for charging compared to batteries, and behave in peculiar ways compared to batteries.

This project from [sciencedude1990] shows off some of the quirks of supercapacitors by showing one method of rapidly charging one. One of the most critical differences between batteries and supercapacitors is that supercapacitors’ charge state can be easily related to voltage, and they will discharge effectively all the way to zero volts without damage. This behavior has to be accounted for in the charging circuit. The charging circuit here uses an ATtiny13A and a MP18021 half-bridge gate driver to charge the capacitor, and also is programmed in a way that allows for three steps for charging the capacitor. This helps mitigate the its peculiar behavior compared to a battery, and also allows the 450 farad capacitor to charge from 0.7V to 2.8V in about three minutes.

If you haven’t used a supercapacitor like this in place of a lithium battery, it’s definitely worth trying out in some situations. Capacitors tolerate temperature extremes better than batteries, and provided you have good DC regulation can often provide power more reliably than batteries in some situations. You can also combine supercapacitors with batteries to get the benefits of both types of energy storage devices.

Game Boy Plays Forever

September 11, 2020 by Bryan Cockfield 14 Comments

For those of us old enough to experience it first hand, the original Game Boy was pretty incredible, but did have one major downside: battery consumption. In the 90s rechargeable batteries weren’t common, which led to most of us playing our handhelds beside power outlets. Some modern takes on the classic Game Boy address these concerns with modern hardware, but this group from the Delft University of Technology and Northwestern has created a Game Boy clone that doesn’t need any batteries at all, even though it can play games indefinitely.

This build was a proof-of-concept for something called “intermittent computing” which allows a computer to remain in a state of processing limbo until it gets enough energy to perform the next computation. The Game Boy clone, fully compatible with the original Game Boy hardware, is equipped with many tiny solar panels which can harvest energy and is able to halt itself and store its state in nonvolatile memory if it detects that there isn’t enough energy available to continue. This means that Super Mario Land isn’t exactly playable, but other games that aren’t as action-packed can be enjoyed with very little impact in gameplay.

The researchers note that it’ll be a long time before their energy-aware platform becomes commonplace in devices and replaces batteries, but they do think that internet-connected devices that don’t need to be constantly running or powered up would be a good start. There are already some low-powered options available that can keep their displays active when everything else is off, so hopefully we will see even more energy-efficient options in the near future.

Thanks to [Sascho] for the tip!

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Visualizing Energy Fields With A Neon Bulb Array

March 4, 2020 by Tom Nardi 20 Comments

Everyone knows that one of the coolest things to do with a Tesla coil is to light up neon or fluorescent tubes at a distance. It’s an easy and very visual way to conceptualize how much energy is being pumped out, making it a favorite trick at science museums all over the world. But what would it look like if you took that same concept and increased the resolution? Replace that single large tube with an array of smaller ones. That’s exactly what [Jay Bowles] did in his latest video, and the results are impressive to say the least.

From a hardware standpoint, it doesn’t get much simpler. [Jay] knew from experience that if you bring a small neon indicator close to a Tesla coil, it will start to glow when approximately 80 volts is going through it. The higher the voltage, the brighter the glow. So he took 100 of these little neon bulbs and arranged them in a 10×10 grid on a piece of perfboard. There’s nothing fancy around the backside either, just all the legs wired up in parallel.

When [Jay] brings the device close to his various high-voltage toys, the neon bulbs still glow like they did before. But the trick is, they don’t all glow at the same brightness or time. As the panel is moved around, the user can actually see the shape and relative strength of the field by looking at the “picture” created by the neon bulbs.

The device isn’t just a cool visual either, it has legitimate applications. In the video, [Jay] explains how it allowed him to observe an anomalous energy field that collapsed when he touched the base of his recently completed Tesla coil; an indication that there was a grounding issue. He’s also observed some dead spots while using what he’s come to call his “High-Voltage Lite-Bright” and is interested in hearing possible explanations for what he’s seeing.

We’ve been fans of [Jay] and the impressively produced videos he makes about his high-voltage projects for years now, and we’re always excited when he’s got something new. Most hardware hackers start getting sweaty palms once the meter starts indicating more than about 24 VDC, so we’ve got a lot of respect for anyone who can build this kind of hardware and effectively communicate how it works to others.

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This Biofuel Cell Harvests Energy From Your Sweat

October 4, 2019 by Sharon Lin 14 Comments

Researchers from l’Université Grenoble Alpes and the University of San Diego recently developed and patented a flexible device that’s able to produce electrical energy from human sweat. The lactate/O2 biofuel cell has been demonstrated to light an LED, leading to further development in the area of harvesting energy through wearables.

The research was published in Advanced Functional Materials on September 25, 2019. The potential use cases for this type of biofuel cell within the wearables space include medical and athletic monitoring. By using biofuels present in human fluids, the devices can rely on an efficient energy source that easily integrated with the human body.

Scientists have developed a flexible conductive material made up of carbon nanotubes, cross-linked polymers, and enzymes connected to each and printed through screen-printing. This type of composite is known as a buckypaper, and uses the carbon nanotubes as the electrode material.

The lactate oxidase works as the anode and the bilirubin oxidase (from the yellowish compound found in blood) as the cathode. Given the theoretical high power density of lactate, this technology has the potential to produce even more power than its current power generation of 450 µW.

The cell follows deformations in the skin and produces electrical energy through oxygen reduction and oxidation of the lactate in perspiration. A boost converter is used to increase the voltage to continuously power an LED. The biofuel cells currently delivered 0.74V of open circuit voltage. As measurements for power generation had to be taken with the biofuel cell against human skin, the device has shown to be productive even when stretched and compressed.

At the moment, the biggest cost for production is the price of the enzymes that transform the compounds in sweat. Beyond cost considerations, the researchers also need to look at ways to increase the voltage in order to power larger portable devices.

With all the exciting research surrounding wearable technology right now, hopefully we’ll be hearing about further developments and applications from this research group soon!

[Thanks to Qes for the tip!]

Electric Dump Truck Produces More Energy Than It Uses

August 22, 2019 by Bryan Cockfield 77 Comments

Electric vehicles are everywhere now. It’s more than just Leafs, Teslas, and a wide variety of electric bikes. It’s also trains, busses, and in this case, gigantic dump trucks. This truck in particular is being put to work at a mine in Switzerland, and as a consequence of having an electric drivetrain is actually able to produce more power than it consumes. (Google Translate from Portugese)

This isn’t some impossible perpetual motion machine, either. The dump truck drives up a mountain with no load, and carries double the weight back down the mountain after getting loaded up with lime and marl to deliver to a cement plant. Since electric vehicles can recover energy through regenerative braking, rather than wasting that energy as heat in a traditional braking system, the extra weight on the way down actually delivers more energy to the batteries than the truck used on the way up the mountain.

The article claims that this is the largest electric vehicle in the world at 110 tons, and although we were not able to find anything larger except the occasional electric train, this is still an impressive feat of engineering that shows that electric vehicles have a lot more utility than novelties or simple passenger vehicles.

Thanks to [Frisco] for the tip!

You Wouldn’t Download A Nuclear Reactor, But Could You?

June 17, 2019 by Tom Nardi 43 Comments

By pretty much any metric you care to use, the last couple of decades has been very good for the open source movement. There was plenty of pushback in the early days, back when the only people passionate about the idea were the Graybeards in the IT department. But as time went on, more and more developers and eventually companies saw the benefit of sharing what they were working on. Today, open source is effectively the law of the land in many fields, and you don’t have to look far to find the community openly denouncing groups who are keeping their source under lock and key.

The open source submarine that won 2017 Hackaday Prize.

In the last few years, we’ve even seen the idea gain traction in the hardware field. While it’s not nearly as prevalent as opening up the software side of things, today it’s not uncommon to see hardware schematics and PCB design files included in project documentation. So not only can you download an open source operating system, web browser, and office suite, but you can also pull down all the information you need to build everything from a handheld game system to an autonomous submarine.

With so many projects pulling back the curtain, it’s not unreasonable to wonder where the limits are. There’s understandably some concerns about the emerging field of biohacking, and anyone with a decent 3D printer can download the files necessary to produce a rudimentary firearm. Now that the open source genie is out of the bottle, it seems there’s precious little that you can’t download from your favorite repository.

Scratching an exceptionally surprising entry off that list is Transatomic, who late last year uploaded the design for their TAP-520 nuclear reactor to GitHub. That’s right, now anyone with git, some uranium, and a few billion dollars of seed money can have their very own Molten Salt Reactor (MSR). Well, that was the idea at least.

So six months after Transatomic dumped a little under 100 MB worth of reactor documentation on GitHub, is the world any closer to forkable nuclear power? Let’s find out.

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Cyborg Mushrooms

November 15, 2018 by Brian McEvoy 3 Comments

Of all the fictional cyborgs who turn against humanity to conquer the planet, this is as far from that possibility as you can get. These harmless mushrooms seem more interested in showing off their excellent fashion sense with a daring juxtaposition of hard grid lines with playful spirals. But the purpose of this bacteria-fungus-technology hybrid is to generate electricity. The mushrooms are there to play nurse to a layer of cyanobacteria, the green gel in the photo, while the straight black lines harvest electricity.

Cyanobacteria do not live very long under these kinds of conditions, so long-term use is out of the question, but by giving the cyanobacteria somewhere it can thrive, the usefulness grows. The interplay between bacterial and supportive organics could lead to advances in sensors and hydrogels as well. At some point, we may grow some of our hardware and a green thumb will be as useful as a degree in computer science.

Hydrogels could be the next medical revolution, and we’ve already made hydrogels into tattoos, used them as forms for artificial muscles, and hydrogels can be a part of soft tissue printing.