Taming A Variac With A Thermistor

The folks at TOG, Dublin Hackerspace, have a large variac. A variac is a useful device for testing some fault conditions with AC mains powered equipment, it allows an operator to dial in any AC output voltage between zero, and in the case of TOG’s variac, 250V.

Their problem was with such a magnificent device capable of handling nearly 3KW, it presented an inductive load with a huge inrush current at power-on that would always take out the circuit breakers. Breakers come with different surge current handling capabilities, evidently their building is fitted with the domestic rather than the industrial variants.

Their solution was a simple one, they fitted an NTC surge limiter in series with the variac input. This is a thermistor whose resistance falls with temperature. Thus on start-up it presented an extra 12 ohm load which was enough to keep the breaker happy, but soon dropped to a resistance which left the variac with enough juice.

This is a simple fix to a problem that has faced more than one hackerspace whose imperfect lodgings are wired to domestic-grade spec. In a way it ties in neatly with our recent feature on mains safety; making the transformer no longer a pain to use means that it is more likely to be used when it is needed.

Via: TOG, Dublin Hackerspace.

Hackaday Links: March 20, 2016

Western Digital introduced their second revision of the PiDrive this week. This is a native USB hard drive – formatted to 314GB – based on the WD Blue drive. The earlier version of the WD PiDrive was 1TB, and cost about $70 USD. The new, 314GB version, sells for about $35. Does Western Digital manufacture 314GB hard drives? No, that would be stupid. Who’s taking bets on the actual capacity of these drives?

[SopaXorsTaker] has introduced us to a brand new way of removing BGA chips. PCBs are usually more flexible than chips, and a few whacks with a hammer is all that’s needed.

For the last few months, [quarterturn] has been upgrading a PowerBook 520. He’s trying to replace the CPU with a 68040 that has an FPU. His first attempt failed, and his second attempt – a new Freescale part that certainly has an FPU – also failed. It’s great experience in desoldering and reworking fine-pitch QFP parts, but [quarterturn] has no idea why the Apple System Profile reports an FPU-less CPU. It might be something in the ROM that tells the PowerBook not to use the FPU, in which case the obvious upgrade would be to replace the ROM with one from a PowerBook 550c or a Sonnet upgrade card. If you have either of those, I’m sure [quarterturn] would like to have a word with you.

LIDAR! We all know what the coolest use of LIDAR is, but it’s also useful for robots, drones, and other autonomous thingamadoos. Here’s a Kickstarter for a LIDAR module, 40 meter range, 360 degree range, 500 samples per second, and UART/USB connections.

[Bill] is trying to start a Makerspace in Fort Lauderdale. Here’s the indiegogo campaign.

We launched the 2016 Hackaday Prize this week. Why should you enter? Because last year, it seemed everyone who entered early won something. There’s $300,000 worth of prizes on the line. Need an idea? [Dave Darko] has just the thing for you. It’s the Hackaday Prize Buzzword Generator, the perfect thing for spitballing a few ideas and seeing what sticks.


Hackers and Heroes: Rise of the CCC and Hackerspaces

From its roots in phone phreaking to the crackdowns and legal precedents that drove hacking mostly underground (or into business), hacker culture in the United States has seen a lot over the last three decades. Perhaps the biggest standout is the L0pht, a visible 1990s US hackerspace that engaged in open disclosure and was, arguably, the last of the publicly influential US hacker groups.

The details of the American hacker scene were well covered in my article yesterday. It ended on a bit of a down note. The L0pht is long gone, and no other groups that I know of have matched their mix of social responsibility and public visibility. This is a shame because a lot of hacker-relevant issues are getting decided in the USA right now, and largely without our input.

Chaos Computer Club

But let’s turn away from the USA and catch up with Germany. In the early 1980s, in Germany as in America, there were many local computer clubs that were not much more than a monthly evening in a cafeteria or a science museum or (as was the case with the CCC) a newspaper office. Early computer enthusiasts traded know-how, and software, for free. At least in America, nothing was more formally arranged than was necessary to secure a meeting space: we all knew when to show up, so what more needed to be done?

Things are a little different in the German soul. Peer inside and you’ll find the “Vereinsmentalität” — a “club-mentality”. Most any hobby or sport that you can do in Germany has an associated club that you can join. Winter biathlon, bee-keeping, watercolor painting, or hacking: when Germans do fun stuff, they like to get organized and do fun stuff together.

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The Rise of the Rural Hacker

On the far side of the Boso peninsula lies Kamogawa. This isn’t the Japan of LEDs, Otaku and maid cafes, or that of wage slave salarymen collapsing from exhaustion. This is the Japan of rice farmers and fields, fresh fish and wild boar, electron microscopes and gigabit fiber, SMD assembly and 500Mhz 5 Gigasample oscilloscopes.

The world has changed. In the 20th century the life of a rural hacker was a constant hunt for technological innovation. We scratched around for whatever we could find. A (usually national) periodical would give its monthly injection of technological curios. And knowledge was locked tight within expensive textbooks, which even if you could afford them might take weeks to arrive.

So, as had been the case for the preceding 1000 years, innovation clustered around technological hubs, San Francisco, Cambridge, and Tokyo among others. And Hackers flocked to these centers where innovation flourished while Hackers exchanged knowledge and tools.

But then the world of the rural Hacker began to expand. The technological hubs that so many rural hackers had migrated to began to connect the world. Young Hackers could learn to program (as I learned C) from textfiles posted on BBSs and exchange knowledge linking national communities. Shortly after that the Internet came bringing its Eternal September. Hackers across the world, regardless of location could communicate.

On the flip-side tech centers were changing too. Venture capital, rather than bootstrapping became the norm. With the influx of cash the demand for skilled Hackers rose, increasing wages and further focusing tech talent around these hubs. But rents and expenses rose too. And Hackers became locked into their expensive lifestyles; eyes firmly focused on the promised million dollar payoff and the eternal dream of an “exit”.

For some though, the freedom to Hack is more important than that million dollar exit and so a new model is emerging. Groups of Hackers in rural communities with low cost lifestyles and access to the world’s best technical talent and equipment that would put the best startups to shame.

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Hackerspace Happenings: Santa Barbara Hackerspace Moving

Occasionally we get a few tips on our hotline telling us of hackerspace happenings. Either a space is moving, they need some help to install a moat around the space, or there’s a mini-conference of weird and esoteric technology happening sometime soon. The latest such tip is from the Santa Barbara Hackerspace. They’re moving, the new space doesn’t have a leaky roof, and they’re looking for some people to help out.

The new space features necessary hackerspace upgrades like no carpet, 120, 220, and 440 Volt outlets, actual parking, and a non-leaky roof. You can get by with a leaky roof in Santa Barbara, but having a roof that doesn’t have holes in it is always a bonus.

Add this to the space’s existing battery of equipment – everything from laser cutters, bandsaws, and welders to oscilloscopes, an amateur radio station, and a forge and anvil, there’s a lot anyone can do in this space.

Hackerspace Tours: Pasadena City College

Pasadena City College is putting together an amazing combination of tools, education techniques, and innovative projects pinning them on the map as one of the best hackerspaces in the Southern California area. Led by [Deborah Bird], the Director of the Design Technology Pathway at PCC, and Sandy Lee the DTP Faculty Chair, this Fab Lab provides students with cutting-edge workshops and internships that will define future jobs.

We were invited to the space by Joan Horvath, the VP of Business Development over at a local 3D printing store called Deezmaker, after meeting her at an Arduino electronics class taught by a young, talented maker named [Quin]. When we arrived, we were greeted by several students who were working on a 3D printed portable map for the blind which was created for an elementary school nearby. The team behind the design attempted to step out of the visual world and into unfamiliar unsighted territory. One of the members gave us a tour of the space showing us the tools and resources they had made available to PCC students. A variety of 3D printers, ventilators, CNC machines, laser cutters, metal lathes, and even a chainsaw were found inside.

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Hackerspace Tour: IXR in Wall, NJ


Hackaday took a little trip out to Wall, NJ last weekend for the Vintage Computer Festival 9.1 East. The event was held at Camp Evans, a former US military installation that can only be described as, ‘The DARPA of a century ago”. This is the site of a Marconi transmitter and the place where [Edwin Armstrong] developed the regenerative receiver a little more than 100 years ago.

There’s a lot more to Camp Evans than a vintage computer festival once a year – it’s also home to MARCH, the Mid-Atlantic Retro Computing Hobbyists, InfoAge, a retro technology museum, and IXR, the Institute for eXploratory Research, a hackerspace located in the old telecom building at Camp Evans.

In our video tour, [Joe Wilkes] takes us around the shop, showing off their equipment and tools. Unlike most of our hackerspace tours, we couldn’t find a Makerbot sitting disused on a bookshelf anywhere, but the space did have a Solidoodle 3D printer, a Shapeoko 2 CNC machine under construction, and enough hand tools to bring any project to fruition.

There were a few oddities in IXR compared to the other hackerspaces we’ve been to. First is an inordinate amount of synths, keyboards, and other MIDI gear. [Joe] didn’t know what these were for, so we’ll leave that explanation for an IXR member in the comments of this post. There was also a small supply of random components for sale (and on display). Most of the merch was from Adafruit, and it seems like a great way to have that one part I need to finish this build for members while providing a little bit of beer money for the space.

Pics and video below.

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