Disinfect PPE On The Cheap With This Hardware Store UV-C Cabinet

April 12, 2020 by 91 Comments

The current situation has given closet germaphobes the world over a chance to get out there and clean the hell out of everything. Some of it may be overdone; we ourselves can cop to a certain excess as we wipe down cans and boxes when returning from a run to the grocery store. But sometimes disinfection is clearly indicated, and having an easy way to kill the bugs on things like face masks can make a big difference by extending the life of something that would normally be disposable. That’s where this quick and easy UV-C germicidal cabinet really shines.

The idea behind [Deeplocal]’s “YouVee” is to be something that can be quickly cobbled together from parts that can be picked up at any big-box home store, thereby limiting the number of trips out. You might even have everything needed already, which would make this a super simple build. The business end is a UV-C germicidal fluorescent lamp, of the kind used in clarifiers for backyard ponds. A fluorescent droplight is modified to accept the lamp by snipping off a bit of plastic, and the lamp is attached to the inside of the lid of a sturdy black plastic tote. The interior of the tote is lined with aluminum tape and a stand for items to be disinfected is made from a paint roller screen. The clever bit is the safety interlock; to prevent exposure to UV, the lamp needs to be unplugged before removing the lid. Check out the full build tutorial for details.

We can’t vouch for YouVee’s germicidal efficacy, but it seems like a solid design. If you have doubts, you could always measure the UV-C flux easily, or you could build a smaller version of this peroxide vapor PPE sterilizer, just to be sure.

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Clever Suction For Robot Arm Automates Face Shield Production

April 12, 2020 by 9 Comments

We’re certainly familiar with vacuum grabbers used in manufacturing to pick items up, but this is a bit different. [James Wigglesworth] sent in some renders and demo video (embedded after the break) of the Dexter robot arm and a laser cutter automatically producing face shields.

It’s a nice little bit of automation, where you can see a roll of plastic on the right side of the Glowforge laser cutter feeding into the machine. Once the laser does its thing, the the robot arm reaches in and grabs the newly cut face shield and stacks it in a box neatly for future assembly. There are a lot of interesting parts here, but the fact that the vacuum grabber is doing it’s job without a vacuum air supply is the one we have our eye on.

The vacuum comes from a corrugated sleeve that makes up the suction cup on the end of the robot arm. A rubber band holds a hinged piece over a valve on that sleeve that can be opened or closed by a servo motor. When the cuff is compressed against the face shield, the servo closes the valve, using the tape as a gasket, and the corrugated nature of the cuff creates a vacuum due to the weight of the item it is lifting. This means you don’t need a vacuum source plumbed into the robot, just a wire to power the servo.

The robot arm is of course the design that won the 2018 Hackaday Prize. I comes as no surprise to see the Haddington Dynamics crew setting up a manufacturing line like this one. As we discovered a few weeks ago, 3D printers, laser cutters, and robot arms are part of their microfactory setup and well suited to making PPE to help reduce the shortage during the COVID-19 outbreak.

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8mm Film Scanner Grows Into A Masterpiece

April 12, 2020 by 73 Comments

Digitizing film is a tedious process that becomes a lot more fun if you spend more of your time building a digitizer and less time actually working working with old film. [Heikki Hietala] has been at it for years and his Kotokino Mark IV film scanner is a masterpiece of simple machine building.

Since we first saw the film scanner four years ago it’s undergone a number of excellent improvements. Most notably, the point-and-shoot camera has been swapped out for a DSLR. With the use of a macro reversing ring a normal lens is flipped around to blow up the 8-millimeter-wide film to take advantage of all the megapixels available on the camera sensor.

The key to the setup is the film advancer mechanism which takes care of both advancing the film and triggering the camera. As you can see, a servo motor rotating an axle provides the locomotion. The mechanism keys into the perforations in the film to pull it along on the down stroke and closes a switch to trigger the camera on the upstroke. Directly under the lens, the alignment jig uses lens cleaning fabric to avoid scratching the film, while perfectly positioning it over the light source.

Previous versions have placed the camera on the horizontal plane but it seems some vibrations in the system caused alignment problems between captured frames. This latest version places the camera pointed straight down to solve that issue, and brings the entire thing together into one beautiful finished project. Having gathered numerous fans of the build along the way, [Heikki] has made the design files available so that you may build your own version.

Software-Defined Radio Made Easy

April 11, 2020 by 25 Comments

Just a few decades ago, getting into hobby radio meant lots of specialty hardware, and making changes to your setup to work on various frequencies wasn’t particularly easy. Since software-defined radio (SDR) came onto the scene in an accessible way for most of us, this barrier to entry was reduced significantly and made the process of getting on the air a lot easier. It goes without saying that it does require some software, but [Aaron]’s latest project makes even getting that software extremely simple.

What he has done is created a custom Linux distribution based on Debian, called DragonOS, with the entire suite of SDR programs needed to get up and running. Out of the box, it supports RTL-SDR, HackRF and LimeSDR packages and even includes other fun tools you’ll need like Kismet. There are several video demonstrations of his distribution, including using RTL-SDR for ADS-B reception, and also shows off several custom implementations of the OS in various scenarios on his YouTube channel. The video linked below also shows how to set up the distribution in a virtual machine, so you can run this even if you don’t have a computer to dedicate to SDR.

Getting into SDR has never been easier, and the odds of having something floating around in the junk drawer that you can use to get started are pretty high. The process is exceptionally streamlined with [Aaron]’s software suite. If you’re a little short on hardware, though, there’s no better place to get started than with the classic TV-tuner-to-SDR hack from a few years back.

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$100k To Crack A Bitcoin Wallet

April 11, 2020 by 43 Comments

When Bitcoin peaked a few years ago, with single coins reaching around $18,000 USD, heartbreaking stories began circulating about people who had tens or hundreds of coins they mined in the early days when coins were worth just a few dollars or cents. Since then, they owners of these coins had lost the private key, or simply thrown away the drive or computer the coins were on. It’s next to impossible to recover this key in most situations, but for the right amount of money it can sometimes be done.

About 20 years ago, [Mike] was working as a cryptography expert and developed a number of interesting algorithms for breaking various forms of encryption, one of which involved .zip files with poor entropy. A Bitcoin owner stumbled across the paper that [Mike] wrote and realized that it could be a method for recovering his lost key from 2016. [Mike] said it would take a GPU farm and $100,000 USD, but when the owner paid the seemingly enormous price [Mike] was able to recover around $300,000 worth of Bitcoin.

While this might not be financially feasible for you if you have a USB stick with a single coin on it you mined as a curiosity in 2010, the cryptography that is discussed in the blog entry is the real story here. We never know where the solutions to our problems are going to come from, like a random .zip file exploitation from two decades ago, but we can be sure that in the future it will be much easier to crack these keys.

Thanks to [Darmstatium] for the tip!

Bike Lock Secures Car

April 11, 2020 by 13 Comments

[Buttim] loses his car a lot, which might sound a little bit like the plot from an early-00s movie, but he assures us that it’s a common enough thing. In a big city, and after several days of not driving one’s car, it can be possible to at least forget where you parked. There are a lot of ways of solving this problem, but the solution almost fell right into his lap: repurposing a lock from a bike share bicycle. (The build is in three parts: Part 2 and Part 3.)

These locks are loaded with features, like GPS, a cellular modem, accelerometers, and in this case, an ARM processor. It took a huge amount of work for [Buttim] to get anything to work on the device, but after using a vulnerability to dump the firmware and load his own code on the device, spending an enormous amount of time trying to figure out where all the circuit traces went through layers of insulation intended to harden the lock from humidity, and building his own Python-based programmer for it, he has basically free reign over the device.

To that end, once he figured out how it all worked, he put it to use in his car. The device functions as a GPS tracker and reports its location over the cellular network so it can’t become lost again. As a bonus, he was able to use the accelerometers to alert him if his car was moving without him knowing, so it turned into a theft deterrent as well. Besides that, though, his ability to get into the device’s firmware reminded us of a recent attempt to get access to an ARM platform.

Unique Musical Instrument Defies Description

April 11, 2020 by 17 Comments

Since the first of our ancestors discovered that banging a stick on a hollow log makes a jolly sound, we hominids have been finding new and unusual ways to make music. We haven’t come close to tapping out the potential for novel instruments, but then again it’s not every day that we come across a unique instrument and a new sound, as is the case with this string-plucking robot harp.

Named “Greg’s Harp” after builder [Frank Piesik]’s friend [Gregor], this three-stringed instrument almost defies classification. It’s sort of like a harp, but different, and sort of like an electric guitar, but not quite. Each steel string has three different ways to be played: what [Frank] calls “KickUps”, which are solenoids that strike the strings; an “eBow” coil stimulator; and a small motor with plastic plectra that pluck the strings. Each creates a unique sound at the fundamental frequency of the string, while servo-controlled hoops around each string serve as a robotic fretboard to change the notes. Sound is picked up by piezo transducers, and everything is controlled by a pair of Nanos and a Teensy, which takes care of MIDI duties.

Check out the video below and see if you find the sound both familiar and completely new. We’ve been featuring unique instruments builds forever, from not-quite-violins to self-playing kalimbas to the Theremincello, but we still find this one enchanting.

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