Month: June 2017

12-Foot Guitar Takes The Stage

June 24, 2017 by 1 Comment

Musical festivals are fun and exciting. They are an opportunity for people to perform and show-off their art. The Boulevardia event held this June in Kansas City was one such event, where one of the interactive exhibits was a 12-foot guitar that could be played. [Chris Riebschlager] shares his experience making this instrument which was intended to welcome the visitors at the event.

The heart of this beautiful installation is a Bare Conductive board which is used to detect a touch on the strings. This information is sent over serial communication to a Raspberry Pi which then selects corresponding WAV files to be played. Additional arcade buttons enable the selection of playable chords from A through G, both major and minor and also give the option to put the guitar in either clean or dirty mode.

The simplicity of construction is amazing. The capacitive touch board is programmed using the Arduino IDE and the code is available as a Gist. The Raspberry Pi runs a Python script which makes the system behave like an actual guitar i.e. touching and holding the strings silences it while releasing the strings produces the relevant sound. The notes being played were exported guitar notes from Garage Band for better consistency.

The physical construction is composed of MDF and steel with the body and neck of the guitar milled on a CNC machine. Paint, finishing and custom decals give the finished project a rocking appearance. Check out the videos below for the fabrication process along with photos of the finished design.

This project is a great example of art enabled by technology and if you love guitars, then go ahead and check out Brian May’s Handmade Guitar. Continue reading “12-Foot Guitar Takes The Stage” →

Fail Of The Week: Tracking Meteors With Weather Radio

June 24, 2017 by 22 Comments

It’s not hard to detect meteors: go outside on a clear night in a dark place and you’re bound to see one eventually. But visible light detection is limiting, and knowing that meteors leave a trail of ions means radio detection is possible. That’s what’s behind this attempt to map meteor trails using broadcast signals, which so far hasn’t yielded great results.

Passing jet’s Doppler signature

The fact that meteor trails reflect radio signals is well-known; hams use “meteor bounce” to make long-distance contacts all the time. And using commercial FM broadcast signals to map meteor activity isn’t new, either — we’ve covered the “forward scattering” technique before. The technique requires tuning into a frequency used by a distant station but not a local one and waiting for a passing meteor to bounce the distant signal back to your SDR dongle. Capturing the waterfall display for later analysis should show characteristic patterns and give you an idea of where and when the meteor passed.

[Dave Venne] is an amateur astronomer who turns his eyes and ears to the heavens just to see what he can find. [Dave]’s problem is that the commercial FM band in the Minneapolis area that he calls home is crowded, to say the least. He hit upon the idea of using the National Weather Service weather radio broadcasts at around 160 MHz as a substitute. Sadly, all he managed to capture were passing airplanes with their characteristic Doppler shift; pretty cool in its own right, but not the desired result.

The comments in the RTL-SDR.com post on [Dave]’s attempt had a few ideas on where this went wrong and how to improve it, including the intriguing idea of using 60-meter ham band propagation beacons. Now it’s Hackaday’s turn: any ideas on how to fix [Dave]’s problem? Sound off in the comments below.

Fake Your ID Photos – The 3D Way

June 24, 2017 by 43 Comments

Photographs for identification purposes have strict requirements. Lighting, expression, and framing are all controlled to enable authorities to quickly and effectively use them to identify individuals reliably. But what if you created an entirely fake photograph from scratch? That’s exactly what [Raphael Fabre] set out to do.

With today’s 3D modelling tools, human faces can be created in extreme detail. Using these, [Raphael] set out to create a 3D model of himself, which was then used to render images simulating a passport photograph. Not content to end the project there, [Raphael] put his digital doppelgänger to the test – applying for a French identification card. He succeeded.

While the technology to create and render high-quality human faces has existed for a while, it’s impressive that [Raphael]’s work passed for genuine human. Obviously there’s something to be said for the likelihood of an overworked civil servant catching this sort of ruse, but the simple fact is, the images made it through the process, and [Raphael] has his ID. Theoretically, this leaves open the possibility of creating entirely fictitious characters and registering them as real citizens with the state, for all manner of nefarious purposes. If you do this, particularly on a grand scale, be sure to submit it to the tip line.

We’ve seen other concerning ID hacks before, such as this attempt at hacking RFIDs in Passport Cards.

Spice Up Your Shop With A VW Pickup Wall Decoration

June 24, 2017 by 10 Comments

Seeing a half car is always a disconcerting experience. Especially when that half car is about 14 feet up in the air. [PanasonicModelRC6015] — We’ll call him [RC6015] for short — has gone and mounted 1/2 (actually more like 1/4) of a VW Rabbit Caddy pickup MK1 up on his shop wall.

The caddy started life as a regular 1983 VW pickup. Unfortunately, the years had not been kind to it. The body panels were in good shape, but there were serious rust problems in the floors, strut towers, rockers, and control arm mounts. According to [RC6015], this is beyond “weld on few replacement panels”, though he’s been heavily questioned on it in his Reddit thread.

Cutting the truck down was easy – a reciprocating saw did most of the work. The VW has a unibody design, so there was still some frame there to hold things together. A 2×12 board then was then bolted from the front of the truck to the rear. This made everything stable and provided a solid mounting point. A second 2×12 was lag bolted to several studs on the wall. Then it was just a matter of lifting the truck into position and bolting the two boards together. We’re guessing the [RC6015]’s wall has solid wood studs. Don’t try hanging a 500 lb truck from the wall if you’ve only got thin metal studs behind your sheetrock.

Just in case you’re wondering, the Panasonic Model RC-6015 is a vintage flip display alarm clock, the same one Marty used in Back to the Future.

If a truck on the wall is a bit much for your shop, check out this wall mounted weather display.

Heathkit’s New RF Meter: Who Is It For?

June 23, 2017 by 25 Comments

Electronic hackers and ham radio operators of a certain age have a soft spot for the Heathkit brand. Maybe that’s why we had a rush of nostalgia when we saw the Heathkit site had a new product. You may recall that Heathkit had gone the way of the dodo until a few years ago when the brand started to resurface. Their latest kit is a precision RF meter which is available on preorder.

Before there were websites and hacker spaces and all the modern push to “do it yourself,” Heathkit was teaching people electronics through kit building. Sure, they were known for ham radio and test equipment, but many people built stereos (hi-fi), TVs, radio control gear, computers, and even robots. All with manuals that are hard to imagine if you haven’t seen one. They were world-class.

Continue reading “Heathkit’s New RF Meter: Who Is It For?” →

EV3DEV Lego Linux Updated

June 23, 2017 by 8 Comments

The ev3dev Linux distribution got an update this month. The distribution targets the Lego EV3 which is a CPU Lego provides to drive their Mindstorm robots. The new release includes the most recent kernel and updates from Debian 8.8. It also contains tools needed for some Wi-Fi dongles and other updates.

If you haven’t seen ev3dev before, it is quite simply Linux that boots on the EV3 hardware using an SD card. You don’t have to reflash the computer and if you want to return to stock, just take out the SD card. You can also use ev3dev on a Raspberry Pi or BeagleBone, if you like. There’s a driver framework included for handling sensors, motors, and other items using the file system.

Continue reading “EV3DEV Lego Linux Updated” →

Nominal Lumber Sizes Land Home Depot And Menards In Hot Water

June 23, 2017 by 181 Comments

Hard times indeed must have fallen upon the lawyers of the American mid-west, for news reaches us of a possible class-action lawsuit filed in Chicago that stretches the bounds of what people in more gainful employment might consider actionable. It seems our legal eagles have a concern over the insufficient dimensions of their wood, and this in turn has caused them to apply for a class action against Home Depot and Menards with respect to their use of so-called nominal sizing in the sale of lumber.

If you have ever bought commercial lumber you will no doubt understand where this is going. The sawmill takes a piece of green wood straight from the forest, and cuts it to a particular size. It is then seasoned, either left to dry out and mature in the open air or placed in a kiln to achieve the same effect at a more rapid pace. This renders it into the workable lumber you expect to use, but causes a shrinkage of the wood that since it depends on variables such as moisture can not be accurately quantified. Thus a piece of wood cut by the sawmill at 4 inches square could produce a piece of seasoned lumber somewhere near 3.5 inches square. It would thus be sold as having only a nominal size of 4 inches This has been the case as long as commercial lumber has been produced, we’d guess for something in the region of a couple of centuries, and is thus unlikely to be a surprise to anyone in the market for lumber.

So, back to the prospective lawsuit. Once the hoots of laughter from the entire lumber, building, and woodworking industries have died down, is their contention that a customer being sold a material of dimension 3.5 inches as 4 inches is being defrauded a valid one? We are not lawyers here at Hackaday, but we’d expect the long-established nature of nominal lumber sizing to present a tough obstacle to their claim, as well as the existence of other nominally sized products in the building industry such as rolled steel joists. Is it uncharitable of us to characterise the whole escapade as a frivolous fishing exercise with the sole purpose of securing cash payouts? Probably not, and we hope the judges in front of whom this is likely to land agree with us.

If you have any thoughts on this case, especially if you have a legal background, we’d love to hear from you in the comments.

Sawn lumber image: By Bureau of Land Management (Oregon_BLM_Forestry_10) [CC BY 2.0].