Listen to your Body

[John Miller] has the perfect response next time he complains about an ache or pain and one of his friends says, “You should listen to your body!” As you can see in the video below, he already does. Using two 9V batteries and some instrumentation amplifiers, [John] built an electromyography (EMG) rig.

If you haven’t heard of EMG, think of EEG or EKG, but for muscles instead of your brain or your heart. The LT1167 amplifier is well-suited for this application and even has a data sheet showing how to create an EMG circuit. [John] also used some more garden-variety op amps and the ubiquitous LM386N chip for audio amplification.

Continue reading “Listen to your Body”

3D-Printed Rover Rolls Light and Looks Right

[Rick Winscott]’s RO-V Remotely Operated Vehicle instructable shows you how to make this cool-looking and capable robot. The rover, a 1/10th scale truggy, sports a chassis printed in silver and black PLA. It’s got a wireless router mounted on the back, and a webcam in a 2-servo gimbal up front. [Rick] made his own steering rack and pinion out of 3D printed parts and brass M3-threaded rods which he tapped himself.

The simplified drive system nixes the front, rear, and center differentials, thereby saving [Rick] on printing time, complexity, and weight — he was able to include a second 4000 mAH battery. A TReX Jr motor controller runs a pair of Pololu gear motors. All of this is controlled by a Beaglebone Black alongside a Spektrum DX6i 2.4Ghz transmitter and an OrangeRx 6-channel receiver. The DX6i [Rick] employs typically finds use as an airplane/quad controller, but he reconfigured it to steer the rover—the left stick controls direction and the right stick (elevator and aileron) control the webcam servos.

Enough talking technicals. We think this rover is pretty in the face. Much of this attraction owes to the set of Dagu Wild Thumper wheels (an entirely reasonable name) and the awe-inspiring 100mm shocks that jack up this whip so pleasingly. However, [Rick]’s elegant chassis and the silver-and-black color scheme doesn’t hurt one bit. The wheels are mostly for the cool factor, however—[Rick] recommends swapping out the relatively modest Pololu 20D gear motors in favor of higher-torque models if you’re planning any actual off-road extremeness. If you’re interested in making your own you can download the chassis files from Tinkercad or the BeagleBone code from Github.

If it’s other drone projects you’re after, check out the duct rover and solar wifi rover we published recently.

A Goldmine Of Radio Shack Goodies Is Up For Auction

Where did you buy the parts for your first electronic project? That’s a question likely to prompt a misty-eyed orgy of reminiscences from many Hackaday readers, if ever we have heard one. The chances are that if you are from North America or substantial parts of the English-speaking world, you bought them from a store that was part of the Radio Shack empire. These modestly sized stores in your local mall or shopping centre carried a unique mix of consumer electronics, CB radio, computers, and electronic components, and particularly in the days before the World Wide Web were one of very few places in which an experimenter could buy such parts over the counter.

Sadly for fans of retail electronic component shopping, the company behind the Radio Shack stores faltered in the face of its new online competition over later years of the last decade, finally reaching bankruptcy in 2015. Gone are all but a few independently owned stores, and the brand survives as an online electronics retailer.

The glory days of Radio Shack may be long gone, but its remaining parts are still capable of turning up a few surprises. As part of the company’s archives they had retained a huge trove of Radio Shack products and memorabilia, and these have been put up for sale in an online auction.

There is such a range if items for sale that if you are like us you will probably find yourself browsing the listings for quite a while. Some of it is the paraphernalia of a corporate head-office, such as framed artwork, corporate logos, or strangely, portraits of [George W. Bush], but the bulk of the collection will be of more interest. There are catalogues galore from much of the company’s history, items from many of its promotions over the years including its ventures into sporting sponsorship, and numerous examples of Radio Shack products. You will find most of the computers, including a significant number of TRS-80s and accessories, tube-based radios and equipment from the 1950s, as well as cardboard boxes stuffed with more recent Realistic-branded items. There are even a few retail technology dead ends to be found, such as a box of :CueCat barcode readers that they evidently couldn’t give away back in the dotcom boom.

If you are interested in any of the Radio Shack lots, you have until the 3rd of July to snap up your personal piece of retail electronic history. Meanwhile if you are interested in the events that led to this moment, you can read our coverage of the retail chain’s demise.

Thanks [Mark Scott] for the tip.

Hackaday Prize Entry: A 3D Printer Management System

Since the first desktop 3D printers, people have been trying to figure out a way to manage desktop 3D printers and turn them into tiny little automated factories. One of the first efforts was a conveyor belt build plate that was successfully used by MakerBot until it wasn’t anymore. Octoprint has been a boon for anyone who wants to manage a few printers, but that’s only half the solution.

For his Hackaday Prize entry, [Mike] has come up with a solution that turns a desktop 3D printer into a completely automated factory. Not only does this project take care of removing the part from the bed when the print is done, it also manages a web-based print queue. It is the simplest way to manage a printer we’ve ever seen, and it’s a great entry for the Hackaday Prize.

First up, the software stack. [Mike] has developed a web-based queue and slicing software that ingests 3D models and spits out Gcode to a printer. This, really, is nothing new. Octoprint does it, Astroprint does it, and even a few 3D printers have this capability. This is only one part of the project though, although it is geared more as a maker space management software than simply a dedicated 3D printer controller.

You can’t have an automated mini factory without an automated build plate, though, and here [Mike] has come up with something really great. His solution for dispensing prints after they’re completed is brilliant in its simplicity. All you need to do is drop the floor out from underneath the print. [Mike]’s solution is a trap door print bed. At the beginning of the print, an inkjet printer spits out a piece of paper, with a few lines of text, onto the print bed. When the print is finished, a stepper motor unwinds a cable, and a trap door opens up underneath the print. The part drops into a bin, the door closes, and the next print is loaded up in the queue. It’s brilliantly simple.

You can check out [Mike]’s demo of this system after the break. It’s awesome and so sublimely simple we’re shocked no one has thought of this before.

Continue reading “Hackaday Prize Entry: A 3D Printer Management System”

12-Foot Guitar Takes The Stage

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

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

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.