Ask Hackaday: Selling Yourself as a Hacker

While there are plenty of hackers that hack just for the love of it, it’s no secret that many of us are looking to hit it big someday. Tales of the businesses like HP and Apple that started in someone’s garage inevitably lead to musings like, “Hey, I’ve got a garage!” and grand plans to turn that special idea into the Next Big Thing™. Many will try, most will fail for one reason or another, but hope springs eternal, and each new widget seems to start the entrepreneurial cycle again.

But for as much pressure as we may feel to be the next Packard, Wozniak, or Musk, not everyone is cut out to be the boss. Some of us have no interest in or aptitude for business — we don’t want to hire or fire people, we don’t want to wheel and deal, and we certainly don’t want to worry about salesmanship. Some of us just want to abstract all that complexity away and just find a job, preferably one that leverages the things we love to do.
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Flush Out Car Thieves with a Key Fob Jammer Locator

We all do it — park our cars, thumb the lock button on the key fob, and trust that our ride will be there when we get back. But there could be evildoers lurking in that parking lot, preventing you from locking up by using a powerful RF jammer. If you want to be sure your car is safe, you might want to scan the lot with a Raspberry Pi and SDR jammer range finder.

Inspired by a recent post featuring a simple jammer detector, [mikeh69] decide to build something that would provide more directional information. His jammer locator consists of an SDR dongle and a Raspberry Pi. The SDR is set to listen to the band used by key fobs for the continuous, strong emissions you’d expect from a jammer, and the Pi generates a tone that varies relative to signal strength. In theory you could walk through a parking lot until you get the strongest signal and locate the bad guys. We can’t say we’d recommend confronting anyone based on this information, but at least you’d know your car is at risk.

We’d venture a guess that a directional antenna would make the search much easier than the whip shown. In that case, brushing up on Yagi-Uda antenna basics might be a good idea.

Hydrodipping 101

Style counts, and sometimes all it takes to jazz up the product of a 3D-printer is a 2D printer and a how-to guide on hydrographic printing.

Hydrographic printing, sometimes called hydrodipping, is a process for transferring graphics onto complex-shaped objects in one simple step. A design is printed on a special film which is then floated on the surface of a tank of water. The object to be decorated is carefully dipped into the water right through the film and the design wraps around all the nooks and crannies in one step.

The video tutorial below details the steps to hydrographic printing and outlines how easy the method has become with the availability of water transfer films for inkjet printers. The film is polyvinyl acetate, which is essentially white glue and hence quite soluble in water. The film dissolves and leaves the ink floating on the surface, ready for dipping.

The video lists quite a few tips for optimizing the process for 3D-printed parts and should let you decorate your parts quickly and easily. And once you master the basics, you might want to look at mathematically warping your design to hydrodip complex surfaces.

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A 3D Scanner that Archimedes Could Get Behind

3D-scanning seems like a straightforward process — put the subject inside a motion control gantry, bounce light off the surface, measure the reflections, and do some math to reconstruct the shape in three dimensions. But traditional 3D-scanning isn’t good for subjects with complex topologies and lots of nooks and crannies that light can’t get to. Which is why volumetric 3D-scanning could become an important tool someday.

As the name implies, volumetric scanning relies on measuring the change in volume of a medium as an object is moved through it. In the case of [Kfir Aberman] and [Oren Katzir]’s “dip scanning” method, the medium is a tank of water whose level is measured to a high precision with a float sensor. The object to be scanned is dipped slowly into the water by a robot as data is gathered. The robot removes the object, changes the orientation, and dips again. Dipping is repeated until enough data has been collected to run through a transformation algorithm that can reconstruct the shape of the object. Anywhere the water can reach can be scanned, and the video below shows how good the results can be with enough data. Full details are available in the PDF of their paper.

While optical 3D-scanning with the standard turntable and laser configuration will probably be around for a while, dip scanning seems like a powerful method for getting topological data using really simple equipment.

Thanks to [bmsleight] for the tip.

World’s Worst Bitcoin Mining Rig

Even if we don’t quite understand what’s happening in a Bitcoin mine, we all pretty much know what’s needed to set one up. Racks of GPUs and specialized software will eventually find a few of these vanishingly rare virtual treasures, but if you have enough time, even a Xerox Alto from 1973 can be turned into a Bitcoin mine. As for how much time it’ll take [Ken Shirriff]’s rig to find a Bitcoin, let’s just say that his Alto would need to survive the heat death of the universe. About 5000 times. And it would take the electricity generated by a small country to do it.

Even though it’s not exactly a profit center, it gives [Ken] a chance to show off his lovingly restored Alto. The Xerox machine is the granddaddy of all modern PCs, having introduced almost every aspect of the GUI world we live in. But with a processor built from discrete TTL chips and an instruction set that doesn’t even have logical OR or XOR functions, the machine isn’t exactly optimized for SHA-256 hashing. The fact that [Ken] was able to implement a mining algorithm at all is impressive, and his explanation of how Bitcoin mining is done is quite clear and a great primer for cryptocurrency newbies.

[Ken] seems to enjoy sending old computer hardware to the Bitcoin mines — he made an old IBM mainframe perform the trick a while back. But if you don’t have a room-size computer around, perhaps reading up on alternate uses for the block chain would be a good idea.

[via Dangerous Prototypes]

Shed Pounds and Inches while Binge Watching Netflix

Feel like breaking out of your streaming-induced vegetative state but can’t seem to break the binge-watching cycle? Maybe you’re a candidate for this exercise bike that controls how much Netflix you watch.

The concept behind [Roboro]’s anti-couch potato build is simple — just keep pedaling and you get to keep watching. The details are pretty simple too and start with an Arduino monitoring the signal coming from a jack thoughtfully provided by the manufacturer of his exercise bike. The frequency of the square wave is translated into a speed which a Python script on a PC reads over USB. Once a Netflix stream is started, dropping below the user-defined speed pauses the movie. The video below shows it doing its thing.

Improvements readily spring to mind, like adding a speed buffer so that pedaling faster lets you bank some streaming time and earn a rest. Maybe it could somehow integrate with these Netflix-enabled socks, or even with the Netflix and Chill button. But those sort of defeat the purpose a bit.

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Automate the Freight: The Robotic Garbage Man

When I started the Automate the Freight series, my argument was that long before the vaunted day when we’ll be able to kick back and read the news or play a video game while our fully autonomous car whisks us to work, economic forces will dictate that automation will have already penetrated the supply chain. There’s much more money to be saved by carriers like FedEx and UPS cutting humans out of the loop while delivering parcels to homes and businesses than there is for car companies to make by peddling the comfort and convenience of driverless commuting.

But the other end of the supply chain is ripe for automation, too. For every smile-adorned Amazon package delivered, a whole bunch of waste needs to be toted away. Bag after bag of garbage needs to go somewhere else, and at least in the USA, municipalities are usually on the hook for the often nasty job, sometimes maintaining fleets of purpose-built trucks and employing squads of workers to make weekly pickups, or perhaps farming the work out to local contractors.

Either way you slice it, the costs for trash removal fall on the taxpayers, and as cities and towns look for ways to stretch those levies even further, there’s little doubt that automation of the waste stream will start to become more and more attractive. But what will it take to fully automate the waste removal process? And how long before the “garbage man” becomes the “garbage ‘bot”?

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