A Graphene Mouth Screen

September 14, 2020 by Brian McEvoy 32 Comments

We are all intimate with face coverings to slow the spread of the coronavirus. Some are reusable, and some become waste after one use. [Dr. Ye Ruquan] and a research team from City University of Hong Kong, CityU, are developing an inexpensive reusable mask with outstanding antibacterial properties, and, get this, the graphene it contains will generate a tiny current when moistened by human breath. There isn’t enough power to charge your phone or anything, but that voltage drops as the masks get dirty, so it can help determine when it needs cleaning. The video after the break shows the voltage test, and it reminds us of those batteries.

All the remarkable qualities of this mask come from laser-induced graphene. The lab is producing LIG by lasering polyimide film with a commercial CO2 infrared model. In a speed test, the process can convert 100cm² in ninety seconds, so the masks can be made more cheaply than an N95 version with that melt-blown layer that is none too good for the earth. Testing the antibacterial properties against activated carbon fiber and blown masks showed approximately 80% of the bacteria is inert after 8 hours compared to the others in the single digits. If you put them in the sun for 10 minutes, blown fabric goes to over 85%, but the graphene is 99.998%, which means that one bacteria in 50K survives. The exact mechanism isn’t known, but [Dr. Ye] thinks it may have something to do with graphene’s sharp edges and hydrophobic quality. A couple of coronavirus species were also affected, and the species that causes COVID-19 will be tested this year.

An overly damp mask is nothing to sneeze at, so keep yourself in check and keep yourself fabulous.

Continue reading “A Graphene Mouth Screen” →

Give Me A Minute, My Eyes Are Busy

September 11, 2020 by Brian McEvoy 3 Comments

Social cues are tricky, but humans are very good at detecting where someone is looking; that goes a long way toward figuring out where someone is placing their attention. All of this goes right out the window though, when you’re talking with somebody who uses eye-tracking software to speak. [Matthew Oppenheim] with Lancaster University, UK wants to give listeners the message of Give Me a Minute with an easy-to-recognize indicator. His choice is a microBit, which displays a rotating arrow on the LED array while someone composes their speech. He chose the microBit because they are readily available, and you can get cases to fit people’s personalities. After the break, you can see a demonstration, but the graphic appears scrambled because of the screen flicker. The rotating arrow is a clear indicator that someone is writing, whereas a clock might suggest a frozen computer, and a progress bar could not be accurate.

[Matthew] wrote a program for the interpreting computer which recognizes when a message is forming by monitoring the number of black pixels in the composition field. If it changes, someone must be composing a sentence. Many people will try to peek over the speaker’s shoulder and see if they are working, but we’re sure that most readers would join the users of such tech in being unhappy if someone blatantly looks at theirr computer screen while they are typing.

Wheelchairs don’t always have to come from a hospital or supply store, and they don’t have to stay on the ground.

Continue reading “Give Me A Minute, My Eyes Are Busy” →

E4 Empatica device for measuring location, temperature, skin conductance, sleep, etc. on arm

Choosing The Optimal Sampling Rate For Your DIY Heart Rate Monitor

September 3, 2020 by Orlando Hoilett 19 Comments

With wearables still trying to solidify themselves in the consumer health space, there are a number of factors to consider to improve the reliability of such devices in monitoring biometrics. One of the most critical such parameters is the sampling rate. By careful selection of this figure, developers can minimize errors in the measurement, preserve power, and reduce costs spent on data storage. For this reason, [Brinnae Bent] and [Dr. Jessilyn Dunn] wanted to determine the optimal sampling rate for wrist-worn optical heart rate monitors. We’ve shared their earlier paper on analyzing the accuracy of consumer health devices, so they’ve done a lot of work in this space.

The results of their paper probably don’t surprise anyone. The lower the sampling rate, the lower the accuracy of the measurement, and the higher the sampling rate the more accurate the measurement when compared to the gold standard electrocardiogram. They also found that metrics such as root mean square of successive differences (RMSSD), used for calculating heart rate variability, requires sampling rates greater than 64 Hz, the nominal sampling rate of the wearable they were investigating and of other similar devices. That might suggest why your wearable is a bit iffy when monitoring your sleeping habits. They even released the source code for their heart rate variability analysis, so there’s a nice afternoon read if you were looking for one.

What really stood out to us about their work is how they thoroughly backed up their claims with data. Something crowdfunding campaigns could really learn from.

Cerebral Palsy Tool Assistant

September 3, 2020 by Brian McEvoy 2 Comments

We all deserve to create. Some people seem to have the muses hidden in their pocket, but everyone benefits when they express themselves in their chose art form. Each of us has tools, from Dremels to paintbrushes, and many folks here build their own implements. Even if we don’t have our macro-enabled mechanical keyboard or a dual-extrusion printer, we can make due. But what if you couldn’t operate your drill, or mouse, or even a pencil? To us, that would be excruciating and is the reality for some. [Laura Roth] and [Christopher Sweeney] are art teachers designing a tool holder for their students with cerebral palsy so that they can express themselves independently.

On either side of this banner image, you can see pencil drawings from [Sara], who has spastic cerebral palsy. She made these drawings while wearing the tool holder modeled after her hand. Now, that design serves other students and is part of the 2020 Hackaday Prize. The tool holder wraps around the wrist like a wide bracelet. Ribbing keeps its shape, and a tube accepts cylindrical objects, like pencils, styluses, and paintbrushes.The result is that the tip of the pencil is not far from where it would have been if held in the hand, but this sidesteps issues with grip and fine control in hands and fingers.

The print is available as an STL and should be printed with flexible filament to ensure it’s comfortable to wear. Be mindful of digital styluses which may need something conductive between the barrel and user.

Hackers are familiar with the challenges of cerebral palsy, and we’ve enjoyed seeing a variety of solutions over the years like door openers, camera gimbals, and just being altogether supportive.

Fog-Free Mask Hack Solves Mask Versus Glasses Conundrum With Superb Seal

September 2, 2020 by Brian McEvoy 35 Comments

If you have worn a mask and glasses together for more than a quarter of a second, you are probably annoyed that we don’t have a magical solution for foggy lenses. Moisture-laden air is also a good indicator of where unfiltered air is escaping. Most masks have some flexible metal across the nose bridge that is supposed to seal the top, but it is woefully inadequate. The Badger Seal by [David Rothamer] and [Scott Sanders] from the University of Wisconsin-Madison College of Engineering is free to copy during the COVID-19 pandemic, even commercially. It works by running an elastic cord below the jaw and a formable wire over the nose to encourage contact all around both mouth and nose.

You can build your own in three ways. Each configuration is uniquely suited to a different situation. The first design is the easiest to make and should work for most people. The second is best for folks who need a better seal on the lower half of their face, like someone sporting a beard. It can also have ear loops, and that means your 3D printed ear savers have another use. The Madison campus of the University of Wisconsin also has fun with lock cracking and graphene experiments.
Continue reading “Fog-Free Mask Hack Solves Mask Versus Glasses Conundrum With Superb Seal” →

Karting Hands-Free

September 1, 2020 by Brian McEvoy 3 Comments

Some of us have computer mice with more buttons than we have fingers, resolution tracking finer than a naked eye can discern, and forced-air vents. All these features presuppose one thing; the user has a functioning hand. [Federico Runco] knows that amyotrophic lateral sclerosis, ALS, or Lou Gehrig’s disease, will rob a person of their ability to use standard computer inputs, or the joystick on a motorized wheelchair. He is building EyesDrive for the 2020 Hackaday Prize, to restore that mobility to ALS patients. There are already some solutions, but this one focuses on a short bill of materials.

Existing systems are expensive and often track pupil location, which returns precise data, but EyesDrive only discerns, left, right, and resting. For these, we need three non-invasive electrodes, a custom circuit board with amplifiers, signal processing circuits, and a microcontroller. He includes a Bluetooth socket on the custom PCBs, which is the primary communication method. In the video below he steers a virtual kart around a knotty course to prove that his system is up to the task of an urban wheelchair.

EyesDrive by [Federico Runco] should not be confused with the HackadayPrize2015 winner, Eyedrivomatic, lead by two remarkable hackers, Steve Evans and Patrick Joyce.

Continue reading “Karting Hands-Free” →

Read My Lips, Under This No-Sew Mask

August 30, 2020 by Brian McEvoy 5 Comments

Humans continuously communicate with our bodies, and face masks cover one of the most expressive parts. For some, this is a muffler on strangers, but devastating for people who rely on lip-reading. Several masks exist that have a clear window for precisely this purpose, but they’re specialty and high-demand. [Erin St Blaine] over at Adafruit shows how she makes windowed masks with stuff you may already have in your house. Even if your sewing machine is locked up the local maker-space, you are in luck, because you don’t need a single stitch. For the thread-inclined, it is easy to tweak the recipe.

The part of the mask that touches your face is terry cloth, but any breathable cotton towel should work. There is a PDF in the instructions where you can print templates in four sizes. You will also find a cutout for the plastic window salvaged from your cold soft drink cup. A water bottle should work too. Flexible glue holds the fabric together, but to attach the ear-loops, we fall back on our old friend, the red Swingline. If you don’t have that color and brand, any stapler will do in a pinch. Don’t forget to add some defogger and keep smiling.

Wear your homemade mask proudly and fasten it well, but not too fast.

Continue reading “Read My Lips, Under This No-Sew Mask” →