Building A Custom Interface For Surplus HF Radios

July 26, 2012 by Mike Szczys 12 Comments

[PRC148] picked up a Motorola Micom radio from eBay. These are US State Department surplus, but apparently the 125 Watt HF units are top-of-the-line at a tenth of the sticker price. The one hangup is that they’re headless; you can’t control them without additional hardware. But the Internets are often kind to the hobbyists, and this is no exception. You can get software to run the radio from a PC thanks to the Micom Yahoo Group. [PRC148] took that software as an example and built his own stand-alone interface. [Cached version of the page]

The head unit is an Arduino driving a four-line LCD display and a rather large array of buttons. The forum thread linked above shows his humble beginnings on a breadboard. During the project [PRC148] learned a lot of skills to end up with what you see above. Hiding behind the reused bezel is a PCB he designed in Eagle CAD and etched himself. It allowed him to cram the tactile switches close enough to work with the button overlay on this keypad.

UPDATE: The traffic from this feature took down the forum hosting the content. They requested that we do not link to them because of this. A cached version without images can be found above thanks to [Termm].

A Mixer (re)built To Travel

July 26, 2012 by Mike Szczys 11 Comments

[Toby Cole] likes to mix tunes whenever he gets a chance. But the size of his DJ equipment made it a real bother to lug around with him. He does own a Behringer portable mixer but without cross faders it’s not really all that usable, and most of the other offerings don’t get good reviews. He ended up replacing the enclosure of a proper mixer in order to make it light and small. The growing availability of affordable laser-cut parts made this project possible.

Build Brighton, [Toby’s] local Hackerspace, has a laser cutter. So he knew that if he could figure out a smaller case design it would be a snap to get his parts made. He cracked open the heavy metal case on the KMX 100 mixer and found it had a ton of extra room inside. He designed all of the plates using a digital calipers to properly space the holes and text labels. These designs were combined with BoxMaker to produce the files the laser cutter needed. The first prototype was cut from cardboard, with the finished product cut from 3mm plywood.

Fabricating Your Own Backpack Straps For Unorthodox Uses

July 25, 2012 by Mike Szczys 14 Comments

Back in the 1980’s there was a movie cliché that the person with the largest boombox on their shoulder was always the coolest. It’s obvious to us that [Tim Gremalm] thinks that’s silly. Why be uncomfortable carrying something like that on your shoulder when you can strap a much larger object to your back? He’s working on a mammoth speaker enclosure which can be carried around, but he needed a set of backpack straps to make it happen.

This thing is going to be adding some serious weight to his body, so he also whipped up the padded waist belt seen above. For fabric he reused an Ikea couch cover. The material is made to survive a lot of pulling and stretching. For padding he used what he calls ‘floor mop’. It looks like it might be microfiber mop cloth be we can’t really be sure. With ten layers of the mop encased in the couch cover he finish off each strap by sewing it to some nylon webbing.

After the break you can see a picture of [Tim] modelling the huge polycarbonate speaker enclosure for which these backpack and waist straps were made. This project has many posts associated with it so if you’re interested in seeing more you can use this project tag link.

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Lighting Controller Counts How Many People Are In A Room

July 25, 2012 by Mike Szczys 32 Comments

[Deekshith Allamaneni] built this controller which will automatically turn the lights in a room on and off. No big deal, right? You can already get a replacement light switch at the home store that will do this for you. But there is one big difference. The commercial solutions we’ve seen simply rely in a motion sensor and a timer. But [Deekshith] found a way to count the number of people that enter a room, turning the lights on when the first person enters and off when the last person leaves.

The video after the break shows a demo of his test rig. At first we just thought that this was only counting how many times an object passes between the sensors. But it can also detect in which direction that object was traveling. Now the system just needs to be scaled up for use in a doorway.

It would be a great addition to the house that doesn’t have any light switches.

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Spinning-hell Of A Game

July 25, 2012 by Mike Szczys 26 Comments

North Street Labs really brought their ‘A’ game to the build finals for the Red Bull Creation contest. Behold the Centrifury, their spinning hell of a game. You can’t really make it out (because of the spinning) but the game consists of two bucket seats positioned opposite of each other on a merry-go-round type deck. Each player has a button in front of them which must be held down for the rig to start spinning. When you can’t take it any more just release the button and the spinning will stop. But you’ll also have lost the game. Whomever can hold out longer wins.

It’s not surprising to see such a well-polished build. After all, this is the same group that built the violently vibrating game of Simon. This time around most of the work came in the form of engineering and welding. First they had to make sure the design could take the forces this things puts out, then they had to build it. And all within the 72-hour time limit. We’re not sure what’s harder, winning the game or trying not to smile while watching the video after the break.

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New Cameras Learning Old Lens Tricks

July 25, 2012 by Mike Szczys 13 Comments

[Michael H] tipped us off about this guide to using view camera lens parts with DSLR cameras and lenses. We weren’t familiar with the term ‘view camera’ but we certainly recognize the accordion-like bellows that define that type of camera. The idea is that modern cameras with their fixed lenses miss out on some types of shots. Why not work out a way to get the best from both old and new?

The concept behind the view camera is that there are two plates connected by the bellows. One plate holds the film and shutter, the other holds the lens. The two can be adjusted for focal length but can also be set at an angle to each other. This modern adaptation uses an adjustable frame to hold the two plates in position. Custom connectors were made by attaching lens rings to the plates. It’s pretty much the same connection technique as we’ve seen when trying to mate cameras with lenses from a different maker.

Arduino, Resistor, And Barrel Plug Lay Waste To Millions Of Hotel Locks

July 25, 2012 by Mike Szczys 63 Comments

The security flaws on this common hotel keycard lock are nothing short of face-palmingly stupid. Look closely at the picture above. This is a hotel room door swinging open. The device he holds in his hand is an Arduino connected to the OUTSIDE portion of the door lock. It takes approximately 200 milliseconds from the time an attacker plugs the device in, until the door can be opened. Yes, in less than 1/4 of one second an Arduino can open any of the millions of these locks in service.

The exploit in Onity programmable keycard locks was revealed by [Cody Brocious] at the Blackhat conference. Apparently the DC barrel jack on the outside of the lock serves as a one-wire protocol interface. Once communications are established a 32-bit sitecode can be read from any of the locks and immediately used to open the door. There is no authentication or encryption used to obfuscate this kind of attack. To make matters worse, you can even read out master key and skeleton key codes. These codes facilitate ‘magic’ keys used to open a variety of different doors through the system.

We’re no strangers to easy hotel beak-ins. But how can a digital lock possibly be sold with this type of vulnerability present? Really!?

Here’s the white paper on the exploit as well as the slides from his talk (PDF).

[via Reddit]