3D Printed Stethoscope Makes the Grade

On the off chance that initiatives like the Hackaday Prize didn’t make it abundantly clear, we believe strongly that open designs can change the world. Putting technology into the hands of the people is a very powerful thing, and depending on where you are or your station in life, can quite literally mean the difference between life and death. So when we saw that not only had a team of researchers developed a 3D printable stethoscope, but released everything as open source on GitHub, it’s fair to say we were pretty interested.

The stethoscope has been in development for several years now, but has just recently completed a round of testing that clinically validated its performance against premium brand models. Not only does this 3D printed stethoscope work, it works well: tests showed its acoustic performance to be on par with the gold standard in medical stethoscopes, the Littmann Cardiology III. Not bad for something the researchers estimate can be manufactured for as little as $3 each.

All of the 3D printed parts were designed in OpenSCAD (in addition to a Ruby framework called CrystalSCAD), which means the design can be evaluated, modified, and compiled into STLs with completely free and open source tools. A huge advantage for underfunded institutions, and in many ways the benchmark by which other open source 3D-printable projects should be measured. As for the non-printed parts, there’s a complete Bill of Materials which even includes links to where you can purchase each item.

The documentation for the project is also exceptional. It not only breaks down exactly how to print and assemble the stethoscope, it even includes multi-lingual instructions which can be printed out and distributed with kits so they can be assembled in the field by those who need them most.

From low-cost ultrasounds to truly personalized prosthetics, the future of open source medical devices is looking exceptionally bright.

[Thanks to Qes for the tip]

Reverse Engineer An X-Ray Image Sensor

If you think of a medical x-ray, it is likely that you are imagining a photographic plate as its imaging device. Clipped to your tooth by your dentist perhaps, or one of the infamous pictures of the hands of [Thomas Edison]’s assistant [Clarence Madison Dally].

As with the rest of photography, the science of x-ray imaging has benefited from digital technology, and it is now well established that your hospital x-ray is likely to be captured by an electronic imaging device. Indeed these have now been in use for so long that their first generation can even be bought by an experimenter for an affordable sum, and that is what the ever-resourceful [Niklas Fauth] with the assistance of [Jan Henrik], has done. Their Trophy DigiPan digital x-ray image sensor was theirs for around a hundred Euros, and though it’s outdated in medical terms it still has huge potential for the x-ray experimenter.

The write-up is a fascinating journey into the mechanics of an x-ray sensor, with the explanation of how earlier devices such as this one are in fact linear CCD sensors which track across the exposed area behind a scintillator layer in a similar fashion to the optical sensor in a flatbed scanner. The interface is revealed as an RS422 serial port, and the device is discovered to be a standalone unit that does not require any commands to start scanning. On power-up it sends a greyscale image, and a bit of Sigrok examination of the non-standard serial stream was able to reveal it as 12-bit data direct from the sensor. From those beginnings they progressed to an FPGA-based data processor and topped it all off with a very tidy power supply in a laser-cut box.

It’s appreciated that x-rays are a particularly hazardous medium to experiment with, and we note from their videos that they are using some form of shielding. The source is a handheld fluoroscope of the type used in sports medicine that produces a narrow beam. If you remember the discovery of an unexpected GameBoy you will be aware that medical electronics seems to be something of a speciality in those quarters, as do autonomous box carriers.

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Hacked 3D TV Glasses May Cure Lazy Eye

Lazy eye (technically Amblyopia) is a sight disorder that affects about 3% of the population where one eye is stronger than the other. Historically, treatment is via an eyepatch or special drops, but research shows that it may be better not to cover up the strong eye for long periods. It suggests that occluding the eye for short periods using a liquid crystal panel can yield better results. To that end, [Raninn] decided to hack some LCD glasses meant for 3D TV viewing to make a low-cost lazy eye treatment device.

This is his second version of [Raninn’s] glasses. The first one took two batteries and didn’t generate enough voltage for the LCD panels. The newer design uses a Dickson charge pump to generate a higher voltage from the battery and surface mount MOSFETs to switch voltages to the panels.

The write up is very complete with details about how to create even the PC board. He didn’t get into a lot of details about hacking the glasses. We assume that’s because your glasses may be different from his. These shutter glasses aren’t too complicated, you’ll just need to find the connections to the panel.

One of our favorite shutter glasses hacks came from [Dino] who built a set of automatic sunglasses for himself. Many of us wear glasses and for those with bifocals we keep waiting for an eyeglasses hack that makes automatic mult-focals a reality.

Print, Rinse, Wear. Nanowire Circuits For Your Microfibre Clothing.

While our bodies are pretty amazing, their dynamic nature makes integrating circuits into our clothing a frustrating process.  Squaring up against this challenge, a team of researchers from North Carolina State University have hit upon a potential boon for wearable electronics: silver nanowires capable of being printed on flexible, stretchy substrates.

It helps that the properties of silver nanowires lend themselves to the needs of wearable circuits — flexible and springy in their own right — but are not without complications. Silver nanowires tend to clog print nozzles during printing, so the research team enlarged the nozzle and suspended the nanowires in a water-soluble solvent, dramatically cutting the chance of clogging. Normally this would have a negative impact on precision, but the team employed electrostatic force to draw the ink to the desired location and maintain print resolution. Once printed, the solvent is rinsed away and the wearable circuit is ready for use.

By controlling print parameters — such as ink viscosity and concentration — the team are able to print on a wide variety of materials. Successful prototypes thus far include a glove with an integrated heating circuit and an electrocardiograph electrode, but otherwise the size of the printer is the only factor limiting the scale of the print. Until this technique becomes more widely available, interested parties might have to put their stock into more homebrew methods.

[Thanks for the tip, Qes!]

CIPODS: Earbuds for Cochlear Implants

If you wear cochlear implants, sound doesn’t enter through your ear, but rather from microphones above your ears. That means earbuds are useless and you have to resort to large and clumsy over the ear headphones. [Mjcraig23] wanted the convenience of earbuds and set out to do what we all do: hack it.

The result is handily portable as you can see in the video, below. The trick is that he used replacement battery covers and then grafted earbud holders (called EARBUDi) to them using one of our favorite fasteners, zip ties. Apparently, you can wire a cable directly into the device, but then you lose the ability to hear what’s going on around you, which would not be a good idea for catching some tunes while walking your dog or other common earbud use cases.

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DIY Cryogel Sustains Live Cells

We like to think our readers are on the cutting edge. With the advent of CRISPR kits at home and DIY bio blooming in workshops across the world, we wanted to share a video which may be ahead of its time. [The Thought Emporium] has just shown us a way to store eukaryotic cells at room temperature. His technique is based on a paper published in Nature which he links to from the YouTube page, but you can see his video after the break.

Eukaryotic cells, the kind we are made of, have been transported at low temperatures with techniques like active refrigeration, liquid nitrogen, and dry ice but those come with a host of problems like cost, convenience, and portability. Storing the cells with cryogel has been shown to reliably keep the cells stable for up to a week at a time and [The Thought Emporium] made some in his homemade freeze-dryer which he’s shown us before. The result looks like a potato chip, but is probably less nutrious than astronaut ice cream.

If cell transport doesn’t tickle your fancy, cryogel is fascinating by itself as a durable, lightweight insulator similar to Aerogel. You can make Aerogel at home too.
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Homebrew Wrist Brace Helps Beat Injury with Style

Repetitive motion injuries are no joke, often attended by crippling pain and the possibility of expensive surgery with a lengthy recovery. Early detection and treatment is the key, and for many wrist and hand injuries such as [ktchn_creations] case of “Blackberry thumb,” that includes immobilization with a rigid brace.

Sadly, the fiberglass brace her doctor left her with was somewhat lacking in the style department, and rather than being left with something unappealing to wear for half a year, she 3D-printed a stylish and functional wrist immobilizer. Starting in Autocad, she designed the outline of the brace, essentially an unwrapped version of the splint she started with. For breathability as well as aesthetics, a pattern of tessellated hexagons was used. The drawing was then exported to Fusion 360 for modeling and printing in black PLA. We were surprised to see that the brace was printed flat and later heat formed around her wrist, but that makes more sense than printing it in its final wrapped state. With a few velcro straps, the thermoformed brace was ready for service on the long road to recovery.

While [ktchn_creations] stipulates that looks were the motivator here, we’re not unaware that a 3D-printed brace might be more affordable than something dispensed by a doctor. But if you do build your own DIY appliance, whether for bracing your wrist, your knee, or your wayward teeth, you’ll want to run it past your health care provider, of course.