Two views of the M19O2 oxygen concentrator

Design Improvements Make DIY Oxygen Concentrator Even Better

August 18, 2021 by Dan Maloney 8 Comments

A lot of projects we feature on these pages are of the “one and done” variety — tactical builds that serve a specific purpose with little need for further development. Some projects, though, come out as rough prototypes and then go through multiple rounds of refinement, a process we really enjoy tracking down and following. And when the project is something as important as an oxygen concentrator that can be built and maintained easily, all the better.

The need for cheap oxygen concentrators stems directly from the COVID-19 pandemic, which suggested that high-flow oxygen therapy was a better choice than invasive intubations and mechanical ventilation. But medical-grade oxygen isn’t always easy to come by in all parts of the world, so easily built oxygen concentrators, which rely on the nitrogen-adsorbing properties of the mineral zeolite, are meant to fill the gaps. Early versions of the M19O2 and the related OxyKit concentrator, had a very homebrew feel to them, built on wooden frames as they were. And while the rustic nature of the early builds didn’t detract from their utility, the hackers behind them, including our own [Anool Mahidharia], have been making incremental improvements aimed at not only making the devices work better, but also making them easier to build.

The hackers at Maker’s Asylum have done a fantastic job at documenting their work, with everything posted to a GitHub repo so that anyone can undertake a build. And really, for something as important as making oxygen when it’s needed, there’s really no reason not to give this a try.

A Stress Monitor Designed Specifically To Help You Work From Home

August 11, 2021 by Orlando Hoilett 10 Comments

There are quite a bit of mixed emotions regarding working from home. Some people love it and are thriving like they haven’t before, but others are having a bit of a hard time with it all. [Brandon] has been working from home for the last 12 years, but even after so many years of managing this type of work culture, he admits that it can still be a little stressful. He says he doesn’t take enough time in between tasks to simply relax and to breathe a little and the day-to-day minutia of his work can drive his stress level up if he doesn’t take some time to calm himself. He figured he could make something to monitor his stress level and remind himself to take a break and the results are pretty impressive.

He develops a system to monitor his heart rate and the ambient noise level in his room and uses these metrics as a measure of stress. If his heart rate or the ambient noise level goes above a certain threshold, then he sends himself a text message reminding himself to relax and take a break. You’ve probably seen people use heart rate as a measure of stress already, but you’re probably less familiar with using sound. [Brandon] basically thought the sound sensor would detect if he starts ranting for prolonged periods of time or if he’s in a Zoom meeting that gets too heated. We thought that was pretty neat.

[Brandon] used an off-the-shelf chest strap heart rate monitor to save himself a bit of time in trying to build his own. The device sends heart rate data to an nRF52840 over Bluetooth and then pushes the data to the cloud using a Blues Wireless Notecard. The Notecard also offers data encryption which gave [Brandon] some added peace of mind knowing his biometric data wasn’t floating around in the cloud without any sort of protection. This certainly isn’t medical-grade encryption, but it gave him a bit of comfort, nonetheless. All that data is processed in his custom-designed web app and when the appropriate thresholds are reached, he sends a text message to himself using Twilio reminding him to relax and unwind for a bit.

For his next iteration, [Brandon] might try making his own heart rate monitor. But until then, stay safe everybody, and remember to take a break whenever you need it.

Continue reading “A Stress Monitor Designed Specifically To Help You Work From Home” →

Charles Lindbergh The Famous… Inventor?

August 10, 2021 by Al Williams 25 Comments

Most people remember Charles Lindbergh for his non-stop solo flight across the Atlantic which made him an international celebrity. If you are a student of history, you might also know he was at the center of a very controversial trial surrounding the kidnapping of his child or even that he had a dance named after him. But did you know he was also the co-inventor of a very important medical device? Turns out, medicine can thank Lindbergh for the creation of the perfusion pump.

Continue reading “Charles Lindbergh The Famous… Inventor?” →

Permanent Artificial Hearts: Long-Sought Replacements May Not Be Far Away

August 9, 2021 by Dan Maloney 44 Comments

The number of artificial prosthetic replacement parts available for the human body is really quite impressive. From prosthetic eyes to artificial hips and knees, there are very few parts of the human body that can’t be swapped out with something that works at least as well as the original, especially given that the OEM part was probably in pretty tough shape in the first place.

But the heart has always been a weak spot in humans, in part because of the fact that it never gets to rest, and in part because all things considered, we modern humans don’t take really good care of it. And when the heart breaks down past the point where medicine or surgery can help, we’re left with far fewer alternatives than someone with a bum knee would face. The fact is that the best we can currently hope for is a mechanical heart that lets a patient live long enough to find a donor heart. But even then, tragedy must necessarily attend, and someone young and healthy must die so that someone else may live.

A permanent implantable artificial heart has long been a goal of medicine, and if recent developments in materials science and electrical engineering have anything to say about it, such a device may soon become a reality. Heart replacements may someday be as simple as hip replacements, but getting to that point requires understanding the history of mechanical hearts, and why it’s not just as simple as building a pump.

Continue reading “Permanent Artificial Hearts: Long-Sought Replacements May Not Be Far Away” →

RNA Therapeutics And Fighting Diseases By Working With The Immune System

July 26, 2021 by Maya Posch 75 Comments

Before the SARS-CoV-2 pandemic took hold, few people were aware of the existence of mRNA vaccines. Yet after months of vaccinations from Moderna and BioNTech and clear indications of robust protection to millions of people, it now seems hard to imagine a world without mRNA vaccine technology, especially as more traditional vaccines seem to falter against the new COVID-19 variants and the ravages of so-called ‘Long COVID’ become more apparent.

Yet, it wasn’t that long ago that Moderna and BioNTech were merely a bunch of start-ups, trying to develop profitable therapies for a variety of diseases, using the brand-new and largely unproven field of RNA therapeutics. Although the use of mRNA in particular for treatments has been investigated since 1989, even as recently as 2017 there were still many questions about safe and effective ways to deliver mRNA into cells, as per Khalid A. Hajj et al.

Clearly those issues have been resolved now in 2021, which makes one wonder about the other exciting possibilities that mRNA delivery offers, from vaccines for malaria, cancer, HIV, as well as curing autoimmune diseases. How did the field of mRNA vaccines develop so quickly, and what can we expect to see the coming years?

Continue reading “RNA Therapeutics And Fighting Diseases By Working With The Immune System” →

Virginia Apgar May Have Saved Your Life

July 13, 2021 by Kristina Panos 28 Comments

Between the 1930s and the 1950s, something sort of strange happened in the United States. The infant mortality rate went into decline, but the number of babies that died within 24 hours of birth didn’t budge at all. It sounds terrible, but back then, many babies who weren’t breathing well or showed other signs of a failure to thrive were usually left to die and recorded as stillborn.

As an obstetrical anesthesiologist, physician, and medical researcher, Virginia Apgar was in a great position to observe fresh newborns and study the care given to them by doctors. She is best known for inventing the Apgar Score, which is is used to quickly rate the viability of newborn babies outside the uterus. Using the Apgar Score, a newborn is evaluated based on heart rate, reflex irritability, muscle tone, respiratory effort, and skin color and given a score between zero and two for each category. Depending on the score, the baby would be rated every five minutes to assess improvement. Virginia’s method is still used today, and has saved many babies from being declared stillborn.

Virginia wanted to be a doctor from a young age, specifically a surgeon. Despite having graduated fourth in her class from Columbia University College of Physicians and Surgeons, Virginia was discouraged from becoming a surgeon by a chairman of surgery and encouraged to go to school a little bit longer and study anesthesiology instead. As unfortunate as that may be, she probably would have never have created the Apgar Score with a surgeon’s schedule. Continue reading “Virginia Apgar May Have Saved Your Life” →

Tuning Into Medical Implants With The RTL-SDR

July 11, 2021 by Tom Nardi 12 Comments

With a bit of luck, you’ll live your whole life without needing an implanted medical device. But if you do end up getting the news that your doctor will be installing an active transmitter inside your body, you might as well crack out the software defined radio (SDR) and see if you can’t decode its transmission like [James Wu] recently did.

Before the Medtronic Bravo Reflux Capsule was attached to his lower esophagus, [James] got a good look at a demo unit of the pencil-width gadget. Despite the medical technician telling him the device used a “Bluetooth-like” communications protocol to transmit his esophageal pH to a wearable receiver, the big 433 emblazoned on the hardware made him think it was worth taking a closer look at the documentation. Sure enough, its entry in the FCC database not only confirmed the radio transmitted a 433.92 MHz OOK-PWM encoded signal, but it even broke down the contents of each packet. If only it was always that easy, right?

The 433 ended up being a coincidence, but it got him on the right track.

Of course he still had to put this information into practice, so the next step was to craft a configuration file for the popular rtl_433 program which split each packet into its principle parts. This part of the write-up is particularly interesting for those who might be looking to pull data in from their own 433 MHz sensors, medical or otherwise

Unfortunately, there was still one piece of the puzzle missing. [James] knew which field was the pH value from the FCC database, but the 16-bit integer he was receiving didn’t make any sense. After some more research into the hardware, which uncovered another attempt at decoding the transmissions from the early days of the RTL-SDR project, he realized what he was actually seeing was the combination of two 8-bit pH measurements that are sent out simultaneously.

We were pleasantly surprised to see how much public information [James] was able to find about the Medtronic Bravo Reflux Capsule, but in a perfect world, this would be the norm. You deserve to know everything there is to know about a piece of electronics that’s going to be placed inside your body, but so far, the movement towards open hardware medical devices has struggled to gain much traction.