Hackaday Prize Entry: Stroke Rehabilitation Through Biofeedback

July 10, 2017 by John Baichtal 8 Comments

Students at Purdue University’s Weldon School of Biomedical Engineering created ExoMIND, an Arduino-powered glove that helps a stroke victim recover by tracking the range of motion the patient experiences.

A set of 7 accelerometers in the fingers, wrist, and forearm track the range of movements the patient is experiencing with that hand. An accelerometer on the back of the hand serving as a reference. Meanwhile, an EMG sensor working with a conductive fabric sleeve to measure muscle activity. The user follows a series of instructions dished out by an interactive software program, allowing the system to test out the patient’s range of motion at the beginning of the regime as well as to record whether any improvement was noted at the end. The data is used by a physical therapist to personalize the treatment plan. The interactive program also raises the possibility of patients self-directing their exercises with the ExoMIND telling them how to adjust their motion to get the most out of the experience.

Produced as part of the university’s MIND Biomedical Engineering Club, the ExoMIND prototype was designed by three interdisciplinary teams focusing on electronics, materials, and programming, respectively.

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Anyone Need A Little Fuming Nitric Acid?

July 7, 2017 by Dan Maloney 67 Comments

If there’s a chemical with a cooler name than “fuming nitric acid,” we can’t think of it. Nearly pure nitric acid is useful stuff, especially if you’re in the business of making rocket fuels and explosives. But the low-end nitric acid commonly available tops out at about 68% pure, so if you want the good stuff, you’ll have to synthesize fuming nitric acid yourself. (And by “good stuff”, we mean be very careful with the resulting product.)

Fuming nitric acid comes in two colors – red fuming nitric acid (RFNA), which is about 90% pure and has some dissolved nitrogen oxides, giving it its reddish-brown color. White fuming nitric acid (WFNA) is the good stuff — more than 99% pure. Either one is rough stuff to work with — you don’t want to wear latex or nitrile gloves while using it. It’s not clear what [BarsMonster] needs the WFNA for, although he does mention etching some ICs. The synthesis is pretty straightforward, if a bit dangerous. An excess of sulfuric acid is added to potassium nitrate, and more or less pure nitric acid is distilled away from the resulting potassium sulfate. Careful temperature control is important, and [BarsMonster] seems to have gotten a good yield despite running out of ice.

We don’t feature too many straight chemistry hacks around here, but this one seemed gnarly enough to be interesting. We did have a Hackaday Prize entry a while back on improvements to the Haber process for producing ammonia, which curiously is the feedstock for commercial nitric acid production processes.

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Gecko Feet In Space

July 5, 2017 by Dan Maloney 31 Comments

Space is a mess, and the sad truth is, we made it that way. Most satellites that have been lofted into Earth orbit didn’t have a plan for retiring them, and those dead hulks, along with the various bits of jetsam in the form of shrouds, fairings, and at least one astronaut’s glove, are becoming a problem.

A mission intended to clean up space junk would be fantastically expensive, but money isn’t the only problem. It turns out that it’s really hard to grab objects in space unless they were specifically designed to be grabbed. Suction cups won’t work in the vacuum of space, not everything up there is ferromagnetic, and mechanical grippers would have to deal with a huge variety of shapes, sizes, and textures.

But now news comes from Stanford University of a dry adhesive based on the same principle a gecko uses to walk up a wall. Gecko feet have microscopic flaps that stick to surfaces because of Van der Waals forces. [Mark Cutkosky] and his team’s adhesive works similarly, adhering to surfaces only when applied in a certain direction. This is an advantage over traditional pressure-sensitive adhesives; the force needed to apply them would cause the object to float away in space. The Stanford grippers have been tested on the “vomit comet” and aboard the ISS.

We can think of tons of terrestrial applications for this adhesive, including the obvious wall-walking robots. The Stanford team also lists landing pads for drones that would let then perch in odd locations, which we find intriguing.

Need to get up to speed on more mundane adhesive? Check out our guide to sticky stuff for the shop.

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A Minority Report Arduino-Based Hand Controller

June 23, 2017 by Al Williams 14 Comments

Movies love to show technology they can’t really build yet. Even in 2001: A Space Oddessy (released in 1968), for example, the computer screens were actually projected film. The tablet they used to watch the news looks like something you could pick up at Best Buy this afternoon. [CircuitDigest] saw Iron Man and that inspired him to see if he could control his PC through gestures as they do on that film and so many others (including Minority Report). Although he calls it “virtual reality,” we think of VR as being visually immersed and this is really just the glove, but it is still cool.

The project uses an Arduino on the glove and Processing on the PC. The PC has a webcam which tracks the hand motion and the glove has two Hall effect sensors to simulate mouse clicks. Bluetooth links the glove and the PC. You can see a video of the thing in action, below.

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Retrotechtacular: The Transistor (1953 Film)

May 29, 2017 by Jenny List 17 Comments

If we cast our minds back to the early years of the transistor, the year that is always quoted is 1947, during which a Bell Labs team developed the first practical germanium point-contact transistor. They would go on to be granted the Nobel Prize for their work in 1956, but the universal adoption of their invention was not an instantaneous process. Instead there would be a gradual change from vacuum to solid state that would span the 1950s and the 1960s, and even in the 1970s you might still have found mainstream devices on sale containing vacuum tubes.

First point contact transistor via kasap3

To speed up this process, Bell Labs made every effort to publicize their invention. Thus we come to our subject today, their 1953 publicity film The Transistor, in which the electronics industry of the era is described and how each part of it might revolutionize by the transistor is laid out.

We start with a look at a selection of electronic components, among which are a few transistors. The point contact device is already described as superceded by the junction transistor, but as well as those two we are shown a phototransistor and a junction tetrode, a now-obsolete design that had two base connections.

Unexpectedly we don’t dive straight into the world of transistors, but take a look back at the earlier years of the century to the development of vacuum electronics. We’re taken through the early development and operation of vacuum tubes, then their use in long-distance radio communications, through the advent of electronics in mass entertainment, and finally into the world of radar and microwave links. Only then do we return to the transistor, with a posed shot of [John Bardeen], [William Shockley], and [Walter Brattain] hard at work in a lab. The merits of the transistor as opposed to the tube are then set out, though we can’t help wondering whether they have confused a milliwatt and a microwatt when they describe the transistor as requiring only a millionth of a watt to operate.

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Intel’s Vision For Single Board Computers Is To Have Better Vision

May 26, 2017 by Mike Szczys 33 Comments

At the Bay Area Maker Faire last weekend, Intel was showing off a couple of sexy newcomers in the Single Board Computer (SBC) market. It’s easy to get trapped into thinking that SBCs are all about simple boards with a double-digit price tag like the Raspberry Pi. How can you compete with a $35 computer that has a huge market share and a gigantic community? You compete by appealing to a crowd not satisfied with these entry-level SBCs, and for that Intel appears to be targeting a much higher-end audience that needs computer vision along with the speed and horsepower to do something meaningful with it.

I caught up with Intel’s “Maker Czar”, Jay Melican, at Maker Faire Bay Area last weekend. A year ago, it was a Nintendo Power Glove controlled quadcopter that caught my eye. This year I only had eyes for the two new computing modules on offer, the Joule and the Euclid. They both focus on connecting powerful processors to high-resolution cameras and using a full-blown Linux operating system for the image processing. But it feels like the Joule is meant more for your average hardware hacker, and the Euclid for software engineers who are pointing their skills at robots but don’t want to get bogged down in first-principles of hardware. Before you rage about this in the comments, let me explain.

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Hackaday Prize Entry: Analyzing And Controlling Hand Tremors

May 3, 2017 by Kristina Panos 6 Comments

For the millions of people suffering from Parkinson’s and other causes of hand tremor, there is new hope in the form of [mohammedzeeshan77]’s entry into the Hackaday Prize: a glove that analyzes and controls the tremors.

The glove uses an accelerometer and a pair of flex sensors to determine the position of the hand as it oscillates. A Particle Photon crunches the raw data to come up with the frequency and amplitude of the tremors and uploads it to the cloud for retrieval and analysis by medical staff.

Hand tremors can vary in frequency and severity depending on the cause. Some are barely perceptible movements, and others are life-disrupting shakes. By analyzing the frequency and amplitude of these tremors, doctors can better understand a patient’s condition.

The best part of this glove is that it also provides immediate relief to the wearer by stabilizing the hand. A rapidly spinning super precision gyroscope counteracts the tremor oscillations as it tries to maintain its position. The last time we saw innovation like this, it came with a set of attachments.