Levitating Table Makes The Sound Of This Holochess Jukebox

November 22, 2016 by Dan Maloney 3 Comments

A bubbling Wurlitzer juke would be a prized addition to the classic picture of a man cave — brass-railed bar, kegerator, pool table, tin signs and neon on the walls. But it would take a particularly geeky abode to give a proper home to this Millenium Falcon holochess table jukebox. And a particularly awesome one at that.

It all started with a very detailed and realistic replica of a holochess table made by [Jim Shima]’s friend. A lot of time and care went into the prop, and [Jim] was determined not to alter the look while installing the media player gear, consisting of a Raspberry Pi running OSMC and a 160-watt power amp.

The speakers were problematic – there was nowhere convenient to mount them except under the brushed aluminum playing surface of the table. The sound quality was less than acceptable, so rather than poke unsightly holes in the table, [Jim] devised a servo to lift the table while the music is playing.

An LCD monitor and wireless keyboard slightly detract from the overall look; we’ll give [Jim] a pass until he can come up with a holographic display to finish the build right. But we are disappointed that he didn’t use “Mad About Me” by Figrin D’an and the Modal Nodes as the demo tune in the video below.

It’s a nice build, and you’ll want to check out [Jim]’s Hyperdyne Labs for more drool-worthy props and effects. And for another fandom jukebox, look over this jukebox that’s bigger on the inside.

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Heathkit: Getting Closer This Time?

November 21, 2016 by Dan Maloney 82 Comments

We’ve been following the Heathkit reboot for a while now, and it looks like the storied brand is finally getting a little closer to its glory days. I was thumbing through the new issue of QST magazine while I was listening in on a teleconference for the day job – hey, a guy can multitask, can’t he? – when I spied an ad for the Heathkit GC-1006 digital clock, which they brand the “Most Reliable Clock”. As soon as the meeting was over, I headed over to the Heathkit website to check out this latest offering.

I had cautiously high hopes. After the ridiculous, feature-poor, no-solder AM radio kit (although they sensibly followed up with a solder version of that kit) and an overpriced 2-meter ham antenna, I figured there was nowhere for Heathkit to go but up. And the fact that the new kit was a clock was encouraging. I have fond memories of Heathkit clocks from the 80s when I worked in a public service dispatch center; Heathkit clocks were about the only clocks you could get that would display 24-hour time. Could this actually be a kit worth building?

Alas, the advertisement was another one of those wall-of-text things that the new Heathkit seems so enamored of. And like the previous two kits offered, the ad copy is full of superlatives and cutesy little phrases that really turn me off. Then again, most advertising turns me off, so I’m probably not a good gauge of such things. Nor am I sure I’m in the target demographic for this product – in fact, I’m not even sure to whom this product is being marketed. Is it the younger crowd of the maker movement? Or is it the old-timers who want to relive the glory days of Heathkit builds? Given the $100 price, I’d have to say the nostalgia market is the most likely buyer of this one.

To be fair, $100 might not be that much to spend on a decent clock. I’m a bit of a clock snob, and I’ve gotten to the point where I can almost tell which chip is in a clock just by looking at the controls. The feature set of a modern digital clock has converged to a point where every clock has almost exactly the same deficiencies. The GC-1006 claims to address a few of my hot button issues, like not being able to set the time to the exact second – I hate that! An auto-dimming display is nice, as is a 12- or 24-hour display, a 10-minute timer (nice for hams, who are required to ID their station every 10 minutes), and a battery backup that claims to last for 4 weeks.

Is this worth buying? At this point, I’m on the fence. Looking at an unboxing video, it appears to be a high-quality kit, and it would be fun to build. But spending $100 on a clock might be a tough sell to my loan officer.

Still, I think I might take one for the team here so we have a first-hand report of what the new Heathkit is all about. And it would be nice to build another Heathkit product. I’ll let you know how it goes.

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EMG Tutorial Lets You Listen To Your Muscles

November 20, 2016 by Dan Maloney 6 Comments

What with wearable tech, haptic feedback, implantable devices, and prosthetic limbs, the boundary between man and machine is getting harder and harder to discern. If you’re going to hack in this space, you’re going to need to know a little about electromyography, or the technique of sensing the electrical signals which make muscles fire. This handy tutorial on using an Arduino to capture EMG signals might be just the thing.

In an article written mainly as a tutorial to other physiatrists, [Dr. George Marzloff] covers some ground that will seem very basic to the seasoned hacker, but there are still valuable tidbits there. His tutorial build centers around a MyoWare Muscle Sensor and an Arduino Uno. The muscle sensor has snap connectors for three foam electrodes of the type used for electrocardiography, and outputs a rectified and integrated waveform that represents the envelope of the electrical signal traveling to a muscle. [Dr. Marzloff]’s simple sketch just reads the analog output of the sensor and lights an LED if it detects a muscle contraction, but the sky’s the limit once you have the basic EMG interface. Prosthetic limbs, wearable devices, diagnostic tools, virtual reality — the possibilities are endless.

We’ve seen a few EMG interfaces before, mainly of the homebrew type like this audio recorder recruited for EMG measurements. And be sure to check out [Bil Herd]’s in-depth discussion of digging EMG signals out of the noise.

Scrap Bin Mods Move Science Forward

November 20, 2016 by Dan Maloney 12 Comments

A first-time visitor to any bio or chem lab will have many wonders to behold, but few as captivating as the magnetic stirrer. A motor turns a magnet which in turn spins a Teflon-coated stir bar inside the beaker that sits on top. It’s brilliantly simple and so incredibly useful that it leaves one wondering why they’re not included as standard equipment in every kitchen range.

But as ubiquitous as magnetic stirrers are in the lab, they generally come in largish packages. [BantamBasher135] needed a much smaller stir plate to fit inside a spectrophotometer. With zero budget, he retrofitted the instrument with an e-waste, Arduino-controlled magnetic stirrer.

The footprint available for the modification was exceedingly small — a 1 cm square cuvette with a flea-sized micro stir bar. His first stab at the micro-stirrer used a tiny 5-volt laptop fan with the blades cut off and a magnet glued to the hub, but that proved problematic. Later improvements included beefing up the voltage feeding the fan and coming up with a non-standard PWM scheme to turn the motor slow enough to prevent decoupling the stir bar from the magnets.

[BantamBasher135] admits that it’s an ugly solution, but one does what one can to get the science done. While this is a bit specialized, we’ve featured plenty of DIY lab instruments here before. You can make your own peristaltic pump or even a spectrophotometer — with or without the stirrer.

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Portable Classroom Upgrade: Smaller, Cheaper, Faster

November 20, 2016 by Dan Maloney 7 Comments

[Eric] at MkMe Lab has a dream: to build a cheap, portable system that provides the electronic infrastructure needed to educate kids anywhere in the world. He’s been working on the system for quite a while, and has recently managed to shrink the suitcase-sized system down to a cheaper, smaller form-factor.

The last time we discussed [Eric]’s EduCase project was as part of his Hackaday Prize 2016 entry. There was a lot of skepticism from our readers on the goals of the project, but whatever you think of [Eric]’s motivation, the fact remains that the build is pretty cool. The previous version of the EduCase relied on a Ku-band downlink to receive content from Outernet, and as such needed to stuff a large antenna into the box. That dictated a case in the carry-on luggage size range. The current EduCase is a much slimmed-down affair that relies on an L-band link from the Inmarsat satellites, with a much smaller patch antenna. A low-noise amp and SDR receiver complete the downlink, and a Raspberry Pi provides the UI. [Eric]’s build is just a prototype at this point, but we’re looking forward to seeing everything stuffed into that small Pelican case.

Yes, Outernet is curated content, and so it’s not at all the same experience as the web. But for the right use case, this little package might just do the job. And with a BOM that rings up at $100, the price is right for experimenting.

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Stairwell Lights Keep Toddler With Night-Blindness Safe

November 19, 2016 by Dan Maloney 25 Comments

A devastating diagnosis for a young child is every parent’s worst nightmare. All too often there’s nothing that can be done, but occasionally there’s a window of opportunity to make things better for the child, even if we can’t offer a cure. In that case even a simple hack, like a rapid response stairwell light to help deal with night-blindness, can make a real difference.

[Becca] isn’t yet a year old, but she and her parents carry a heavy burden. She was born with Usher Syndrome, an extremely rare genetic disease that affects hearing and vision to different degrees. In [Becca]’s case, she was born profoundly deaf and will likely lose her sight by the time she’s 10 or so. Her dad [Jake] realized that the soon-to-be-toddler was at risk due to a dark stairwell and the night-blindness that accompanies Usher, so he came up with a simple tech solution to the problem.

He chose Philips Hue LED light strips to run up the stringer of the stairs controlled by a Raspberry Pi. Originally he planned to use IFTTT for the job but the latency resulted in the light not switching on fast enough. He ended up using a simple PIR motion sensor which the Pi monitors and then uses the Hue API to control the light. This will no doubt give him a platform for future capabilities to help [Becca].

We’ve covered a few builds where parents have hacked solutions for their kids, like this custom media center for the builder’s autistic son. We suspect [Jake] has a few more tricks up his sleeve to help [Becca], and we’re looking forward to seeing how she does.

Cache Shortwave Signals For Later With This SDR Spectrum Grabber

November 18, 2016 by Dan Maloney 6 Comments

Shortwave listening has always been a mainly nocturnal hobby. To get the real DX, one had to wait for favorable ionospheric conditions after sunset and spend hours twisting knobs while straining to pick voices from half a planet away out of the noise. But who has time for that in today’s world? And what of the poor city-dwelling SWL, with antenna limitations and often elevated noise floor in the urban jungle?
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