Biometric Bracelet Electrifies You To Unlock Your Tablet

Researchers [Christian Holz] and [Marius Knaust] have come up with a cool new way to authenticate you to virtually any touchscreen device. This clever idea couples a biometric sensor and low-data-rate transmitter in a wearable wrist strap that talks to the touch screen by electrifying you.

Specifically the strap has electrodes that couple a 50V, 150kHz signal through your finger, to the touchscreen. The touchscreen picks up both your finger’s location through normal capacitive-sensing methods and the background signal that’s transmitted by the “watch”. This background signal is modulated on and off, transmitting your biometric data.

The biometric data itself is the impedance through your wrist from one electrode to another. With multiple electrodes encircling your wrist, they end up with something like a CAT scan of your wrist’s resistance. Apparently this is unique enough to be used as a biometric identifier. (We’re surprised.)

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Theremin’s Bug: How The Soviet Union Spied On The US Embassy For 7 Years

The man leaned over his creation, carefully assembling the tiny pieces. This was the hardest part, placing a thin silver plated diaphragm over the internal chamber. The diaphragm had to be strong enough to support itself, yet flexible enough to be affected by the slightest sound. One false move, and the device would be ruined. To fail meant a return to the road work detail, quite possibly a death sentence. Finally, the job was done. The man leaned back to admire his work.

The man in this semi-fictional vignette was Lev Sergeyevich Termen, better known in the western world as Léon Theremin. You know Theremin for the musical instrument which bears his name. In the spy business though, he is known as the creator of one of the most successful clandestine listening devices ever used against the American government.

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The Filmomat Home Film Processing System

The death of film has been widely reported, but technologies are only perfected after they’ve been made obsolete. It may not be instant photography, but there is at least one machine that will take 35mm film and 5×7″ prints and develop them automatically. It’s called the Filmomat, and while it won’t end up in the studios of many photographers, it is an incredible example of automation.

The Filmomat is an incredible confabulation of valves, tubes, and pumps that will automatically process any reasonably sized film, from 35mm to 5×7 color slides. The main body of the machine is an acrylic cube subdivided into different sections containing photo processing chemicals, rinse water, and baths. With a microcontroller, an OLED display, and a rotary encoder, different developing processes can be programmed in, the chemicals heated, developer agitated, and film processed. The Filomat is capable of storing fifty different processes that use three chemicals and a maximum of ten steps.

The video for this device is what sells it, although not quite yet; if enough people are interested, the Filmomat might be sold one day. This is likely the easiest film developing will ever get, but then again a technology is only perfected after it has been made obsolete.

Thanks [WhiteRaven] for sending this one in.

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Gitaar Van Schroot – The Scrap Metal Guitar

Sheet metal. Beer cans. Pieces of chain. Not items you’ll typically find on the BOM for a custom guitar. But nobody told [Maarten van Halderen] that, and so he threw them all together into a gitaar van schroot, or scrap guitar for the Dutch impaired (YouTube link).

The video shows the build process, starting with plasma cutting and welding sheet steel for the body. The neck is fabricated from rectangular steel tube, with nails serving as frets. Overall it looks like a Les Paul, except for the sink strainer basket mounted in the sound hole and the crushed beer and soda cans tacked to the body for decoration. The chains are a nice touch too. And this doesn’t appear to be [Maarten]’s first attempt at scrapyard lutherie  – toward the end of the video we see that the beer can axe joins a very steam-punk looking older brother. They’re both good-looking builds, and the video after the break proves they can sound pretty good too.

For a more classical take on the building of string instruments, check out this post on mandolins and violas. Or maybe you can just 3D print your next guitar?

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