DIY Spot Welder Doesn’t Look Like It Will Immediately Kill You

April 24, 2016 by Gerrit Coetzee 30 Comments

We love hacks that involve mains voltage, but most of the time, for safety’s sake, we secretly hope for that one macabre commenter that details every imaginable way the questionable design choices will result in death. This spot welder may still be dangerous, but it looks like they took some precautions to make it non-lethal, and that counts for a lot.

After their extremely questionable high speed belt sander, this one is, refreshingly, extremely well done. It starts of as a dead standard microwave spot welder build: take apart microwave, try not to die from large capacitor, remove coil, modify coil, and hook up.

After that, it gets to some nice heavy metal music fabrication. Aside from a slightly shocking number of fresh OSHA reportable hand injuries (wear gloves!) the build goes together well. A lot of planning obviously went into it, from the actively cooled transformer to what appears to be a resettable timer circuit for the weld duration, not to mention the way that it just fit together so well at the end. There were some neat ideas as far as home mechanics go that we’ll be using in some of our projects.

In the end, the proof is in the spot-weld. The timer is set, pedal gets pressed down, and when tested, the sheet metal breaks instead of the weld. Video after the break.

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A Field Guide To The North American Communications Tower

April 5, 2016 by Kristina Panos 99 Comments

The need for clear and reliable communication has driven technology forward for centuries. The longer communication’s reach, the smaller the world becomes. When it comes to cell phones, seamless network coverage and low power draw are the ideals that continually spawn R&D and the eventual deployment of new equipment.

Almost all of us carry a cell phone these days. It takes a lot of infrastructure to support them, whether or not we use them as phones. The most recognizable part of that infrastructure is the communications tower. But what do you know about them?

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J.C. Bose And The Invention Of Radio

January 19, 2016 by Dan Maloney 68 Comments

The early days of electricity appear to have been a cutthroat time. While academics were busy uncovering the mysteries of electromagnetism, bands of entrepreneurs were waiting to pounce on the pure science and engineer solutions to problems that didn’t even exist yet, but could no doubt turn into profitable ventures. We’ve all heard of the epic battles between Edison and Tesla and Westinghouse, and even with the benefit of more than a century of hindsight it’s hard to tell who did what to whom. But another conflict was brewing at the turn of 19th century, this time between an Indian polymath and an Italian nobleman, and it would determine who got credit for laying the foundations for the key technology of the 20th century – radio.

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32C3: 3D Printing On The Moon

January 3, 2016 by Elliot Williams 36 Comments

How do you resist this talk title? You can’t! [Karsten Becker]’s talk about what kinds of 3D printers you’d use on the moon is a must-see.

[Part-Time Scientists] was a group of 35 people working on a mission to the moon. Then they won the qualifying round in the Google Lunar XPRIZE, got a bunch of money, and partnered with some heavy corporate sponsors, among which is Audi. Now they’ve added eleven full-time employees and updated the name to [PT Scientists]. (They’re taking applications if you’re interested in helping out!)

A really neat part of their planned mission is to land near the Apollo 17 landing site, which will let them check up on the old lunar rover that NASA left up there last time. The science here is that, 45 years on, they hope to learn how all of the various materials that make up the rover have held up over time.

But the main attraction of their mission is experimental 3D printing using in-situ materials. As [Karsten] says, “3D printing is hard…but we want to do it on the moon anyway.”

One idea is to essentially microwave the lunar regolith (and melt it) . This should work because there’s a decent iron component in the regolith, so if they can heat it up it should fuse. The catch with microwaving is directivity — it’s hard to make fine details. On the plus side, it should be easy to make structures similar to paved roads out of melted regolith. Microwave parts are robust and should hold up to launch, and microwaving is relatively energy efficient, so that’s what they’re going to go for.

But there are other alternatives. The European Space Agency is planning to bring some epoxy-like binder along, and glue regolith together in layers like a terrestrial cement printer. The problem is, of course, schlepping all of the binder to the moon in the first place.

And then there are lasers. [Karsten] talked lasers down a little bit, because they’re not very energy efficient and the optics are fidgety — not something you’d like to be supporting remotely from earth.

The final option that [Karsten] mentioned was the possibility of using locally-generated thermite to fuse regolith. This has been tested out on earth, and should work. [Karsten] thought it was an interesting option, but balls of hot thermite are potentially tough on rovers, and the cost of mistakes are so high that they’re going to put that off for a future mission.

In the end, the presentation ran only thirty minutes long, so there’s a great Q&A session after that. Don’t go home once you hear the audience clapping!

Hacklet 80 – Gigahertz Projects

October 16, 2015 by Adam Fabio 7 Comments

Somewhere between the HF projects many of us have worked on, and the visible light spectrum lies the UHF, EHF, SHF, and THF. That’s Ultra, Extremely, Super, and Tremendously High Frequency for those who aren’t in the know. All of them involve frequencies in the gigahertz and terahertz range. While modern computers have made gigahertz a household term, actually working with signals in the gigahertz frequency range is still a daunting prospect. There have always been an elite group of hackers, makers, and engineers who tinker with projects using GHz frequencies. This week’s Hacklet is about some of the best GHz projects on Hackaday.io!

We start with [Luke Weston] and Simple, low-cost FMCW radar. For years people like Hackaday’s own [Gregory L. Charvat] have been building simplified radar systems and documenting them for the rest of us. [Luke’s] goal is to make radar systems like this even more accessible for the average hacker. He’s put all the specialized parts on one board. Rather than large Mini Circuits modules, [Luke] went with Hittite microwave parts in chip scale packages. Modulation comes from a Microchip MCP4921 mixed signal DAC. The system works, and has demonstrated transmission and reception 5 GHz to 6 GHz bands. [Luke] has even demonstrated detection of objects at close range using a scope.

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The EM Drive Might Not Work, But We Get Helicarriers If It Does

August 19, 2015 by Brian Benchoff 226 Comments

There is a device under test out there that promises to take humans to another star in a single lifetime. It means vacations on the moon, retiring at Saturn, and hovercars. If it turns out to be real, it’s the greatest invention of the 21st century. If not, it will be relegated to the history of terrible science right underneath the cold fusion fiasco. It is the EM drive, the electromagnetic drive, a reactionless thruster that operates only on RF energy. It supposedly violates the laws of conservation of momentum, but multiple independent lab tests have shown that it produces thrust. What’s the real story? That’s a little more complicated.

The EM Drive is a device that turns RF energy — radio waves — directly into thrust. This has obvious applications for spacecraft, enabling vacations on Mars, manned explorations of Saturn, and serious consideration of human colonization of other solar systems. The EM drive, if proven successful, would be one of the greatest inventions of all time. Despite the amazing amount of innovation the EM drive would enable, it’s actually a fairly simple device, and something that can be built out of a few copper sheets.

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Modded Microwave Sets Its Own Clock

April 9, 2015 by Ethan Zonca 49 Comments

Of all the appliances in your house, perhaps the most annoying is a microwave with a flashing unset clock. Even though a lot of devices auto-set their time these days, most appliances need to have their time set after being unplugged or after a power outage. [Tiago] switches off power to some of his appliances while he’s at work to save a bit of power, and every time he plugs his microwave back in he has to manually reset the clock.

Thankfully [Tiago] wrote in with his solution to this problem: an add-on to his microwave that automatically sets the time over the network. [Tiago]’s project uses an ESP8266 running the Lua-based firmware we’ve featured before. The ESP module connects to [Tiago]’s WiFi network and pulls the current time off of his Linux server.

Next, [Tiago] ripped apart his microwave and tacked some wires on the “set time” button and on the two output pins of the microwave’s rotary encoder. He ran all three signals through optoisolators for safety, and then routed them to a few GPIO pins on his ESP module. When the microwave and the ESP module are powered up, [Tiago]’s Lua script pulls the time from his server, simulates a press of the “set time” button, and simulates the rotary encoder output to set the microwave’s time.

While [Tiago] didn’t post any detailed information on his build, it looks like a great idea that could easily be improved on (like adding NTP support). Check out the video after the break to see the setup in action.

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