Building A Portable Solar Powered Spot Welder: Charging Supercapacitors

February 28, 2018 by Sean Boyce 48 Comments

Before Lunar New Year, I had ordered two 3000 F, 2.7 V supercapacitors from China for about $4 each. I don’t actually remember why, but they arrived (unexpectedly) just before the holiday.

Supercapacitors (often called ultracapacitors) fill a niche somewhere between rechargeable lithium cells and ordinary capacitors. Ordinary capacitors have a low energy density, but a high power density: they can store and release energy very quickly. Lithium cells store a lot of energy, but charge and discharge at a comparatively low rate. By weight, supercapacitors store on the order of ten times less energy than lithium cells, and can deliver something like ten times lower power than capacitors.

Overall they’re an odd technology. Despite enthusiastic news coverage, they are a poor replacement for batteries or capacitors, but their long lifespan and moderate energy and power density make them suitable for some neat applications in their own right. Notably, they’re used in energy harvesting, regenerative braking, to extend the life of or replace automotive lead-acid batteries, and to retain data in some types of memory. You’re not likely to power your laptop with supercapacitors.

Anyway, I had a week-long holiday, and two large capacitors of dubious origin. Sometimes we live in the best of all possible worlds. Continue reading “Building A Portable Solar Powered Spot Welder: Charging Supercapacitors” →

Can Open-source Hardware Be Like Open-source Software?

February 27, 2018 by Elliot Williams 116 Comments

Hardware and software are certainly different beasts. Software is really just information, and the storing, modification, duplication, and transmission of information is essentially free. Hardware is expensive, or so we think, because it’s made out of physical stuff which is costly to ship or copy. So when we talk about open-source software (OSS) or open-source hardware (OSHW), we’re talking about different things — OSS is itself the end product, while OSHW is just the information to fabricate the end product, or have it fabricated.

The fabrication step makes OSHW essentially different from OSS, at least for now, but I think there’s something even more fundamentally different between the current state of OSHW and OSS: the pull request and the community. The success or failure of an OSS project depends on the community of people developing it, and for smaller projects that can hinge on the ease of a motivated individual digging in and contributing. This is the main virtue of OSS in my opinion: open-source software is most interesting when people are reading and writing that source.

With pure information, it’s essentially free to copy, modify, and push your changes upstream so that others can benefit. The open hardware world is just finding its feet in this respect, but that’s changing as we speak, and I have great hopes. Costs of fabrication are falling all around, open and useful tools are being actively developed to facilitate interchange of the design information. I think there are lessons that OSHW can learn from the OSS community’s pull-request culture, and that will help push the hardware hacker’s art forward.

What would it take to get you to build someone else’s OSHW project, improve on it, and contribute back? That’s a question worth a thoughtful deep dive.

Continue reading “Can Open-source Hardware Be Like Open-source Software?” →

World Create Day Is The Hackaday Event In Your Neighborhood

February 26, 2018 by Mike Szczys 10 Comments

Hackaday World Create Day is on March 17th and it’s happening near you. Get together with hackers in your area and create something. Sign up now to host a World Create Day gathering! These are really easy to organize, but we can only do it with your help.

The Hackaday community from around the world will meetup and spend time building together on Saturday, March 17th. Pick one of those projects you’ve been meaning to dive into and get together with some old and new friends to hack on your projects together.

You should make this day your own. As with any hands-on hacking events it’s a good idea to block out a bit of time at the end for lightning talks to show off the builds everyone has been working on. Make the memories live on past a single day by taking pictures and posting the story of your World Create Day meetup. We enjoyed getting a great look at many of last year’s meetups this way and want to expand the builds we feature on the front page this year.

Meetup Organizers Wanted

Fill out this form to let us know you want to host a meetup.

Every year we have World Create Day meetups all over the world which are set up by local organizers. Many of those will happen again this year, but we also need you to organize an event in your area. We’ll help you get things set up and put your event up on the big map so others in your area will plan to join in. Do it now, if we get your shipping info early we’ll send you stickers and other swag to hand out at your gathering.

Build Something that Matters

The core of World Create Day is to stop making excuses and just build something. Great builds start with a plan. The Hackaday Prize will begin soon, and since you’re already getting together with other people, form a team and dream up your entry.

This is your take on building something that matters to the world. Come up with a plan that solves a problem facing humanity and publish your work on Hackaday.io. You may be surprised by the support you get for your idea, but you’ll never know until you put an idea out there. Join in Hackaday’s World Create Day on March 17th and let’s show the world the kind of hope that blossoms when we decide to build something that matters.

Mechanisms: Mechanical Seals

February 22, 2018 by Dan Maloney 36 Comments

On the face of it, keeping fluids contained seems like a simple job. Your fridge alone probably has a dozen or more trivial examples of liquids being successfully kept where they belong, whether it’s the plastic lid on last night’s leftovers or the top on the jug of milk. But deeper down in the bowels of the fridge, like inside the compressor or where the water line for the icemaker is attached, are more complex and interesting mechanisms for keeping fluids contained. That’s the job of seals, the next topic in our series on mechanisms.

Continue reading “Mechanisms: Mechanical Seals” →

The King Of Machine Tools

February 21, 2018 by Quinn Dunki 68 Comments

The lathe is known as the King of Machine Tools for a reason. There are very few things that you can’t make with one. In fact, people love to utter the old saw that the lathe is the only machine tool that can make itself. While catchy, I think that’s a bit disingenuous. It’s more accurate to say that there are parts in all machine tools that (arguably) only a lathe can make. In that sense, the lathe is the most “fundamental” machine tool. Before you harbor dreams of self-replication, however, know that most of an early lathe would be made by hand scraping the required flat surfaces. So no, a lathe can’t make itself really, but a lathe and a skilled craftsperson with a hand-scraper sure can. In fact, if you’ve read the The Metal Lathe by David J. Gingery, you know that a lathe is instrumental in building itself while you’re still working on it.

We’re taking trip through the machining world with this series of articles. In the previous article we went over the history of machine tools. Let’s cut to the modern chase now and help some interested folks get into the world of hobby machining, shall we? As we saw last time, the first machine tools were lathes, and that’s also where you should start.

Continue reading “The King Of Machine Tools” →

Vera Rubin: Shedding Light On Dark Matter

February 20, 2018 by Kristina Panos 41 Comments

Vera sat hunched in the alcove at Kitt Peak observatory, poring over punch cards. The data was the same as it had been at Lowell, at Palomar, and every other telescope she’d peered through in her feverish race to collect the orbital velocities of stars in Andromeda. Although the data was perfectly clear, the problem it posed was puzzling. If the stars at the edges of spiral galaxy were moving as fast as the ones in the center, but the pull of gravity was weaker, how did they keep from flying off? The only possible answer was that Andromeda contained some kind of unseen matter and this invisible stuff was keeping the galaxy together.

Though the idea seemed radical, it wasn’t an entirely new one. In 1933, Swiss astronomer Fritz Zwicky made an amazing discovery that was bound to bring him fame and fortune. While trying to calculate the total mass of the galaxies that make up the Coma Cluster, he found that the mass calculation based on galaxy speed was about ten times higher than the one based on total light output. With this data as proof, he proposed that much of the universe is made of something undetectable, but undeniably real. He dubbed it Dunkle Materie: Dark Matter.

But Zwicky was known to regularly bad mouth his colleagues and other astronomers in general. As a result, his wild theory was poorly received and subsequently shelved until the 1970s, when astronomer Vera Rubin made the same discovery using a high-powered spectrograph. Her findings seemed to provide solid evidence of the controversial theory Zwicky had offered forty years earlier.

Continue reading “Vera Rubin: Shedding Light On Dark Matter” →

Whatever Happened To The Desktop Computer?

February 16, 2018 by Brian Benchoff 210 Comments

If you buy a computer today, you’re probably going to end up with a laptop. Corporate drones have towers stuffed under their desks. The cool creative types have iMacs littering their open-plan offices. Look around on the online catalogs of any computer manufacturer, and you’ll see there are exactly three styles of computer: laptops, towers, and all-in-ones. A quick perusal of Newegg reveals an immense variety of towers; you can buy an ATX full tower, an ATX mid-tower, micro-ATX towers, and even Mini-ITX towers.

It wasn’t always this way. Nerds of a sufficient vintage will remember the desktop computer. This was, effectively, a tower tilted on its side. You could put your monitor on top, negating the need for a stack of textbooks bringing your desktop up to eye level. The ports, your CD drive, and even your fancy Zip drive were right there in front of you. Now, those days of desktop computers are long gone, and the desktop computer is relegated to history. What happened to the desktop computer, and why is a case specifically designed for a horizontal orientation so hard to find?

Continue reading “Whatever Happened To The Desktop Computer?” →