Air-Powered Wheelchair Goes Like The Wind

Electric wheelchairs are responsible for giving back independence to a great many people the world over. They do have their limitations, however, including long recharge times and a general aversion to large amounts of water. Being weatherproof is one thing, but taking one to a waterpark is another thing entirely. Fear not, for The University of Pittsburgh has the answer: the air-powered wheelchair.

Known as the PneuMobility project, the chair relies on a couple of compressed air tanks as a power source. They appear to be a of composite construction, which would cut down on weight significantly and help reduce risk of injury in the case of a failure. The air is passed through a system of valves to a special compressed air motor, allowing the user to control the direction of travel. Unfortunately details on the drive system are scant — we’d love to know more about the design of the drivetrain! Reportedly a lot of the components come from the local hardware store, though we haven’t seen a whole lot of compressed air drive motors on the racks of Home Depot/Bunnings/et al.

Range for the wheelchairs is listed as about 1/3 of an electric wheelchair but recharging compressed air takes minutes, not hours. Developed by the university’s Human Engineering Research Laboratories, the wheelchair isn’t just a one off. There are plans to supply ten of the machines to the Morgan’s Wonderland amusement park to enable wheelchair users to share in the fun of the water park.

We’ve seen some great wheelchair hacks in the past, too – like this chair built specifically for the sand dunes! Video after the break.

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Hackaday Prize Entry: A Complete Suite Of Biomedical Sensors

The human body has a lot to tell us if we only have the instruments to listen. Unfortunately, most of the diagnostic gear used by practitioners is pricey stuff that’s out of range if you just want to take a casual look under the hood. For that task, this full-featured biomedical sensor suite might come in handy.

More of an enabling platform than a complete project, [Orlando Hoilett]’s shield design incorporates a lot of the sensors we’ve seen before. The two main modalities are photoplethysmography, which uses the MAX30101 to sense changes in blood volume and oxygen saturation by differential absorption and reflection of light, and biopotential measurements using an instrumentation amplifier built around an AD8227 to provide all the “electro-whatever-grams” you could need: electrocardiogram, electromyogram, and even an electrooculogram to record eye movements. [Orlando] has even thrown on temperature and light sensors for environmental monitoring.

[Orlando] is quick to point out that this is an educational project and not a medical instrument, and that it should only ever be used completely untethered from mains — battery power and Bluetooth only, please. Want to know why? Check out the shocking truth about transformerless power supplies.

Thanks to [fustini] for the tip.

Hackaday Prize Entry: Wearable Micro Pump Treats Your Fever For You

Would you strap a tiny pump to your body and let it dose you with medication based on your current vital signs? Most people wouldn’t, while some would appreciate the convenience, and many have no choice. [M. Bindhammer]’s 2017 Hackaday Prize entry, dubbed Sense-Aid, seeks to democratize the drug delivery process somewhat by building a sensor package linked to a tiny surface-mount pump into a single wearable device.

His chosen initial therapeutic area is fever, given that it’s easy to diagnose non-invasively with a simple thermistor and straightforward to treat with antipyretics like acetaminophen. Aside from the obvious regulatory hurdles such a device would face, he’s got a bunch of technical challenges to address. Surprisingly, sourcing a surface-mount pump is not one of them, although finding a medication to pump with it is. Anecdotally, a professor acquaintance of ours used to relate his sure-fire hangover cure: an aspirin tablet dissolved in the polar aprotic solvent dimethyl sulfoxide (DMSO) and absorbed directly through the skin for immediate relief. The story may have been apocryphal, and it certainly sounds like a bad idea, but such solvents may be one way of pumping medications non-invasively.

Obviously, this is only a concept at this point, as [M. Bindhammer] hasn’t even built a prototype yet. But that’s exactly what the first phase of the 2017 Hackaday Prize is all about: Design Your Concept. It may seem like a crazy idea, but at least it’s an idea, and that’s the first step. Have you submitted your idea yet? There’s still plenty of time.

Easy-Peasy Heart Monitor

If you’re at all into medical hacks, you’ve doubtless noticed that the medical industry provides us with all manner of shiny toys to play with. Case in point is a heart-monitoring IC that’s so brand new, it’s not even available in all of the usual distributors yet. [Ashwin], who runs a small prototyping-supplies company, ProtoCentral, has been playing around with the new MAX30003 ECG chip, and the results look great.

The punchline is that the four-to-five dollar chip does everything for you, including analog filtering, wander removal, and even detecting the pulse rate. Using the chip is simple: you plug in two electrodes on one end, and you get the waveform data out over SPI on the other, with little or no work to do on the microprocessor side. The Arduino in the examples is just passing the SPI data straight to the laptop, with no processing going on at all.

[Ashwin] is selling these as breakout boards, but everything is open source, from the hardware to the GUI, so check it out if you’re interested in building your own. In particular, the circuit is just a voltage regulator and five volt level shifter.

Everything we know about electrocardiography projects, we learned from this presentation, and it looks like the devil is in the (many) details, so it’s nice to offload them to custom silicon whenever possible. We just think it’s awesome that we can scoop up some of the giant medical industry’s crumbs to play around with.

Solar-Powered Prosthetic Skin

One of the biggest problems for prosthetic users is feel. If you’ve ever tried to hold a pen and write with a numb hand, you’ve realised how important feedback is to the motor control equation. Research is ongoing to find ways to provide feedback from prosthetic limbs, in even a basic format.  The human nervous system is a little more complex than just interfacing with the average serial UART. One of the requirements of many feedback systems is power, which usually would involve bulky batteries or some form of supercapacitors, but a British team has developed a way to embed solar cells in a touch-sensitive prosthetic skin.

The skin relies on everyone’s favourite material of the minute, graphene. A thin layer of graphene allows the prosthetic to feed signals back to the user of both temperature and contact pressure. The trick is that the graphene skin is incredibly transparent, reportedly allowing 98% of light on its surface to pass through. It’s then a simple matter of fitting solar panels beneath this skin, and the energy harvested can then be used to power the sensor system.

The team does admit that some power storage will later be required, as it would be difficult for any prosthetic user if their limbs lost all feedback when they walked into a dark room. The idea of one’s arm losing all feeling upon going to bed isn’t particularly appealing. Check out the paper here (paywalled). Video below the break.
We see a lot of great prosthetic projects cross our desk here at Hackaday – like this 3D printed prosthetic hand. Prosthetics definitely matter, so why not build your own and enter it in the 2017 Hackaday Prize?

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Scratch-built Camera Gimbal For Photographer With Cerebral Palsy

We so often hack for hacking’s sake, undertaking projects as a solitary pursuit simply for the challenge. So it’s nice to see hacking skills going to good use and helping someone out. Such was the case with this low-cost two-axis handheld camera gimbal intended to help a budding photographer with a motion disorder.

When [Tadej Strah] joined his school photography club, a fellow member who happens to have cerebral palsy needed help steadying cameras for clean shots. So rather than shell out a lot of money for a commercial gimbal, [Tadej] decided to build one for his friend. A few scraps of aluminum bar stock were bent into the gimbal frames and camera mount. Two hobby servos take care of the pitch and roll axes, controlled by an Arduino talking to an MPU-6050. Mounted to a handle from an angle grinder with the battery and electronics mounted below, the gimbal looks well-balanced and does a good job of keeping the camera level.

Hats off to [Tadej] for pitching in and solving a real world problem with his skills. We like to see people helping others directly, whether it’s building a gyroscopic spoon for Parkinson’s sufferers or vision enhancement for a nearly blind adventurer.

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Two Bits A Gander: Of Premature Babies, Incubators, And Coney Island Sideshows

Newborn humans are both amazingly resilient and frighteningly fragile creatures. A child born with a 40 full weeks of gestation has pretty good odds of surviving the neonatal period these days, and even if he or she comes along a few weeks early, things usually go smoothly. But those babies that can’t wait to get out and meet the world can run into trouble, and the earlier they’re born, the greater the intervention needed to save them.

We’ve all seen pictures of remarkably tiny babies in incubators, seemingly dwarfed by the gloved hands of an anxious parent who just wants that first magical touch of their baby’s skin. As common as such an intervention is now and as technologically advanced as neonatology is, care for premature infants as a medical discipline has a long and interesting history of technical and social hacks that’s worth looking at.

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