Grant Anyone Temporary Permissions To Your Computer With SSH

February 5, 2017 by 33 Comments

This is a super cute hack for you Linux users out there. If you have played around with SSH, you know it’s the most amazing thing since sliced bread. For tunneling in, tunneling out, or even just to open up a shell safely, it’s the bees knees. If you work on multiple computers, do you know about ssh-copy-id? We had been using SSH for years before stumbling on that winner.

Anyway, [Felipe Lavratti]’s ssh-allow-friend script is simplicity itself, but the feature it adds is easily worth the cost of admission. All it does is look up your friend’s public key (at the moment only from GitHub) and add it temporarily to your authorized_keys file. When you hit ctrl-C to quit the script, it removes the keys. As long as your friend has the secret key that corresponds to the public key, he or she will be able to log in as your user account.

Continue reading “Grant Anyone Temporary Permissions To Your Computer With SSH” →

Two Guitars, Two Amps, And Three Pole Dual Throw

February 5, 2017 by 10 Comments

[Alexbergsland] plays electric guitar. More accurately, he plays two electric guitars, through two amps. Not wanting to plug and unplug guitars from amps and amps from guitars, he designed an AB/XY pedal to select between two different guitars or two different amps with the press of a button.

The usual way of sending a guitar signal to one amp or another is with an A/B pedal that takes one input and switches the output to one jack or another. Similarly, to switch between two inputs, a guitarist would use an A/B pedal. For [Alex]’ application, that’s two pedals that usually sell for $50, and would consequently take up far too much room on a pedalboard. This problem can be solved with a pair of 3PDT footswitches that sell for about $4 each. Add in a few jacks, LEDs, and a nice aluminum enclosure, and [Alex] has something very cool on his hands.

The circuit for this switcher is fairly simple, so long as you can wrap your head around how these footswitches are wired internally. The only other special addition to this build are a trio of LEDs to indicate which output is selected and if both inputs are on. These LEDs are powered by a 9V adapter embedded in the pedalboard, but they’re not really necessary for complete operation of this input and output switcher. The LEDs in this project can be omitted, making this a completely passive pedal to direct signals around guitars and amps.

Bantam-sized Jukebox Reproduction Tops The Fabrication Charts

February 4, 2017 by 2 Comments

Restoring a genuine vintage jukebox is a fun project, but finding suitable candidates can be a difficult proposition. Not only can a full-size machine take a huge bite out of your wallet, it can take up a lot of room, too. So a replica miniature jukebox might be just the thing.

We have to admit, at first glance [Allan_D_Murray]’s project seemed like just another juke upgrade. It was only after diving into his very detailed build log that we realized this classic-looking juke is only about 30″ (80 cm) tall. It’s not exactly diminutive, but certainly more compact than the original Wurlitzer 1015 from which it draws its inspiration. But it sure looks like the real thing. Everything is custom made, from the round-top case to the 3D-printed trim pieces, which are painted to look like chrome-plated castings. The guts of the juke are pretty much what you’d expect these days — a PC playing MP3s. But an LCD monitor occupies the place where vinyl records would have lived in the original and displays playlists of the albums available. There’s an original-looking control panel on the front, and there are even bubblers in the lighted pilasters and arches.

Hats off to [Allan] for such a detailed and authentic tribute to a mid-century classic. But if a reproduction just won’t cut it for you, check out this full-size juke with the original electronics.

Continue reading “Bantam-sized Jukebox Reproduction Tops The Fabrication Charts” →

Quick And Easy IoT Prototyping With Involt

February 4, 2017 by 20 Comments

IoT, web apps, and connected devices are all becoming increasingly popular. But, the market still resembles a wild west apothecary, and no single IoT ecosystem or architecture seems to be the one bottle of snake oil we’ll all end up using. As such, we hackers are keen to build our own devices, instead of risking being locked into an IoT system that could become obsolete at any time. But, building an IoT device and interface takes a wide range of skills, and those who are lacking skill in the dark art of programming might have trouble creating a control app for their shiny new connected-thing.

Enter Involt, which is a framework for building hardware control interfaces using HTML and CSS. The framework is built on Node-Webkit, which means the conventions should be familiar to those with a bit of web development background. Hardware interactions (on Arduinos) are handled with simple CSS classes. For example, a button might contain a CSS class which changes an Arduino pin from high to low.

Involt can take that CSS and convert it into a function, which is then sent to the Arduino via serial or Bluetooth communication. For more advanced functionality, Javascript (or really any other language) can be used to define what functions are generated — and, in turn, sent to the Arduino. But, all that is needed for the basic functionality necessary for many IoT devices (which might only need to be turned on and off, or set to a certain value) is a bit of HTML and CSS knowledge. You’ll create both the interface and the underlying hardware interactions all within an HTML layout with CSS styling and functionality.

While Involt isn’t the only framework to simplify hardware interaction (it’s not even the only Node.js based method), the simplicity is definitely laudable. For those who are just getting started with these sorts of devices, Involt can absolutely make the process faster and less painful. And, even for those who are experienced in this arena, the speed and efficiency of prototyping with Involt is sure to be useful.

Plywood Steals The Show From Upcycled Broken Glass Art Lamps

February 4, 2017 by 23 Comments

You can tell from looking around his workshop that [Paul Jackman] likes plywood even more than we do. And for the bases of these lamps, he sandwiches enough of the stuff together that it becomes a distinct part of the piece’s visuals. Some work with a router and some finishing, and they look great! You can watch the work, and the results, in his video embedded below.

The plywood bases also hide the electronics: a transformer and some LEDs. To make space for them in the otherwise solid blocks of wood, he tosses them in the CNC router and hollows them out. A little epoxy for the caps of the jars and the bases were finished. Fill the jars with colored glass, and a transparent tube to allow light all the way to the top, and they’re done.

Continue reading “Plywood Steals The Show From Upcycled Broken Glass Art Lamps” →

Live Counter Revives Old Nokia Phone’s Utility

February 4, 2017 by 7 Comments

Old hardware you may have on hand cannot only inspire projects in their own right, but can facilitate the realization of any ideas you have been planning. Using a Nokia N900, [MakerMan] concocted a light-up sign with a live subscriber and view count of his videos.

[MakerMan] milled out the logo used on the sign with his DIY CNC machine — built from rotary bearings and recycled stepper motors off industrial Xerox printers. The meticulous application of a jigsaw, rotary tool, and grinder resulted in a sturdy frame for the sign while a few strips of RGB LEDs imbue it with an inspiring glow. All that was left was to mount the phone in place and tape it for good measure.

Continue reading “Live Counter Revives Old Nokia Phone’s Utility” →

33C3: Memory Deduplication, The Hacker’s Friend

February 4, 2017 by 11 Comments

At the 33rd annual Chaos Communications Congress, [Antonio Barresi] and [Erik Bosman] presented not one, not two, but three (3!!) great hacks that were all based on exploiting memory de-duplication in virtual machines. If you’re interested in security, you should definitely watch the talk, embedded below. And grab the slides too. (PDF)

Memory de-duplication is the forbidden fruit for large VM setups — obviously dangerous but so tempting. Imagine that you’re hosting VMs and you notice that many of the machines have the same things in memory at the same time. Maybe we’re all watching the same cat videos. They can save on global memory across the machines by simply storing one copy of the cat video and pointing to the shared memory block from each of the machines that uses it. Notionally separate machines are sharing memory. What could go wrong?

Continue reading “33C3: Memory Deduplication, The Hacker’s Friend” →