Medical Hacks

668 Articles

Pixel Watch 3’s Loss Of Pulse Detection: The Algorithms That Tell Someone Is Dying

March 12, 2025 by 59 Comments

More and more of the ‘smart’ gadgets like watches and phones that we carry around with us these days come with features that we’d not care to ever need. Since these are devices that we strap onto our wrists and generally carry in close proximity to our bodies, they can use their sensors to make an estimation of whether said body is possibly in the process of expiring. This can be due to a severe kinetic event like a car crash, or something more subtle like the cessation of the beating of one’s heart.

There is a fairly new Loss of Pulse Detection (LoPD) feature in Google’s Pixel Watch 3 that recently got US FDA approval, allowing it to be made available in the US after previously becoming available in over a dozen European countries following its announcement in August of 2024. This opt-in feature regularly polls whether it can detect the user’s pulse. If not found, it cascades down a few steps before calling emergency services.

The pertinent question here is always whether it is truly detecting a crisis event, as nobody wants to regularly apologize for a false alert to the overworked person staffing the 911 or equivalent emergency line. So how do you reliably determine that your smart watch or phone should dial emergencies forthwith?

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The Road To Lucid Dreaming Might Be Paved With VR

March 7, 2025 by 26 Comments

Lucid dreaming is the state of becoming aware one is dreaming while still being within the dream. To what end? That awareness may allow one to influence the dream itself, and the possibilities of that are obvious and compelling enough that plenty of clever and curious people have formed some sort of interest in this direction. Now there are some indications that VR might be a useful tool in helping people achieve lucid dreaming.

The research paper (Virtual reality training of lucid dreaming) is far from laying out a conclusive roadmap, but there’s enough there to make the case that VR is at least worth a look as a serious tool in the quest for lucid dreaming.

One method of using VR in this way hinges on the idea that engaging in immersive VR content can create mild dissociative experiences, and this can help guide and encourage users to perform “reality checks”. VR can help such reality checks become second nature (or at least more familiar and natural), which may help one to become aware of a dream state when it occurs.

Another method uses VR as a way to induce a mental state that is more conducive to lucid dreaming. As mentioned, engaging in immersive VR can induce mild dissociative experiences, so VR slowly guides one into a more receptive state before falling asleep. Since sleeping in VR is absolutely a thing, perhaps an enterprising hacker with a healthy curiosity in lucid dreaming might be inspired to experiment with combining them.

We’ve covered plenty of lucid dreaming hacks over the years and there’s even been serious effort at enabling communication from within a dreaming state. If you ask us, that’s something just begging to be combined with VR.

Smartwatches Could Flatten The Curve Of The Next Pandemic

March 4, 2025 by 72 Comments

While we’d like to think that pandemics and lockdowns are behind us, the reality is that a warming climate and the fast-paced travel of modern life are a perfect storm for nasty viruses. One thing that could help us curb the spread of the next pandemic may already be on your wrist.

Researchers at Aalto University, Stanford University, and Texas A&M have found that the illness detection features common to modern smartwatches are advanced enough to help people make the call to stay home or mask up and avoid getting others sick. They note we’re already at 88% accuracy for early detection of COVID-19 and 90% for the flu. Combining data from a number of other studies on smartwatch accuracy, epidemiology, behavior, and biology, the researchers were able to model the possible outcomes of this early detection on the spread of future diseases.

“Even just a 66-75 percent reduction in social contacts soon after detection by smartwatches — keeping in mind that that’s on a par with what you’d normally do if you had cold symptoms — can lead to a 40-65 percent decrease in disease transmission compared to someone isolating from the onset of symptoms,” says Märt Vesinurm.

We’ve got you covered if you’re looking for a smartwatch that looks a bit like a hospital wristband and we’ve also covered one that’s alive. That way, you’ll have a slimy friend when you’re avoiding other humans this time around. And when it’s time to develop a vaccine for whatever new bug is after us, how do MRNA vaccines work anyway?

A PCR machine with its side cover taken off exposing its guts, and the tray extended out

Making A PCR Machine Crypto Sign Its Results

March 1, 2025 by 20 Comments

Money, status, or even survival – there’s no shortage of incentives for faking results in the scientific community. What can we do to prevent it, or at least make it noticeable? One possible solution is cryptographic signing of measurement results.

Here’s a proof-of-concept from [Clement Heyd] and [Arbion Halili]. They took a ThermoFisher Scientific 7500 Fast PCR (Polymerase Chain Reaction) machine, isolated its daughter-software, and confined it into a pipeline that automatically signs each result with help of a HSM (Hardware Security Module).

A many machines do, this one has to be paired to a PC, running bespoke software. This one’s running Windows XP, at least! The software got shoved into a heavily isolated virtual machine running XP, protected by TEE (Trusted Execution Environment). The software’s output is now piped into a data diode virtual serial port out of the VM, immediately signed with the HSM, and signed data is accessible through a read-only interface. Want to verify the results’ authenticity? Check them against the system’s public key, and you’re golden – in theory.

This design is just a part of the puzzle, given a typical chain of custody for samples in medical research, but it’s a solid start – and it happens to help make the Windows XP setup more resilient, too.

Wondering what PCR testing is good for? Tons of things all over the medical field, for instance, we’ve talked about PCR in a fair bit of detail in this article about COVID-19 testing. We’ve also covered a number of hacker-built PCR and PCR-enabling machines, from deceivingly simple to reasonably complex!

Over The Counter Glucose Monitor Dissected

February 23, 2025 by 37 Comments

If you deal with diabetes, you probably know how to prick your finger and use a little meter to read your glucose levels. The meters get better and better which mostly means they take less blood, so you don’t have to lacerate your finger so severely. Even so, taking your blood several times a day is hard on your fingertips. Continuous monitoring is available, but — until recently — required a prescription and was fairly expensive. [Andy] noticed the recent introduction of a relatively inexpensive over-the-counter sensor, the Stelo CGM. Of course, he had to find out what was inside, and thanks to him, you can see it, too.

If you haven’t used a continuous glucose monitor (CGM), there is still a prick involved, but it is once every two weeks or so and occurs in the back of your arm. A spring drives a needle into your flesh and retracts. However, it leaves behind a little catheter. The other end of the catheter is in an adhesive-backed module that stays put. It sounds a little uncomfortable, but normally, it is hardly noticeable, and even if it is, it is much better than sticking your finger repeatedly to draw out a bunch of blood.

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Integrated Micro Lab Keeps Track Of Ammonia In The Blood

February 17, 2025 by 6 Comments

We’ve all got our health-related crosses to bear, and even if you’re currently healthy, it’s only a matter of time before entropy catches up to you. For [Markus Bindhammer], it caught up to him in a big way: liver disease, specifically cirrhosis. The disease has a lot of consequences, none of which are pleasant, like abnormally high ammonia concentration in the blood. So naturally, [Markus] built an ammonia analyzer to monitor his blood.

Measuring the amount of ammonia in blood isn’t as straightforward as you think. Yes, there are a few cheap MEMS-based sensors, but they tend to be good only for qualitative measurements, and other solid-state sensors that are more quantitative tend to be pretty expensive since they’re mostly intended for industrial applications. [Marb]’s approach is based on the so-called Berthelot method, which uses a two-part reagent. In the presence of ammonia (or more precisely, ammonium ions), the reagent generates a dark blue-green species that absorbs light strongly at 660 nm. Measuring the absorbance at that wavelength gives an approximation of the ammonia concentration.

[Marb]’s implementation of this process uses a two-stage reactor. The first stage heats and stirs the sample in a glass tube using a simple cartridge heater from a 3D printer head and a stirrer made from a stepper motor with a magnetic arm. Heating the sample volatilizes any ammonia in it, which mixes with room air pumped into the chamber by a small compressor. The ammonia-laden air moves to the second chamber containing the Berthelot reagent, stirred by another stepper-powered stir plate. A glass frit diffuses the gas into the reagent, and a 660-nm laser and photodiode detect any color change. The video below shows the design and construction of the micro lab along with some test runs.

We wish [Markus] well in his journey, of course, especially since he’s been an active part of our community for years. His chemistry-related projects run the gamut from a homebrew gas chromatograph to chemical flip flops, with a lot more to boot.

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Graphene Tattoos: The Future Of Continuous Health Monitoring?

February 16, 2025 by 22 Comments

In the near future, imagine a world where your health is continuously monitored, not through bulky devices but through an invisible graphene tattoo. Developed at the University of Massachusetts Amherst, these tattoos could soon detect a range of health metrics, including blood pressure, stress levels, and even biomarkers of diseases like diabetes. This technology, though still in its infancy, promises to revolutionize how we monitor health, making it possible to track our bodies’ responses to everything from exercise to environmental exposure in real-time.

Graphene, a single layer of carbon atoms, is key to the development of these tattoos. They are flexible, transparent, and conductive, making them ideal for bioelectronics. The tattoos are so thin and pliable that users won’t even feel them on their skin. In early tests, graphene electronic tattoos (GETs) have been used to measure bioimpedance, which correlates with blood pressure and other vital signs. The real breakthrough here, however, is the continuous, non-invasive monitoring that could enable early detection of conditions that usually go unnoticed until it’s too late.

While still requiring refinement, this technology is advancing rapidly. Graphene still amazes us, but it’s no longer just science fiction. Soon, these tattoos could be a part of everyday life, helping individuals track their health and enabling better preventative care. Since we’re hackers out here –  but this is a far fetch – combining this knowledge on graphene production, and this article on tattooing with a 3D printer, could get you on track. Let us know, what would you use graphene biosensors for?

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