CT Scans of Health Wearables | Hacker News Reader

CT Scans of Health Wearables

lumafield.com

247 pointsradeeyate52 comments

The entire library of scans on this site is great. It gives me a similar feeling as being a kid and playing around in 'The Way Things Work'[0].

[0] https://www.youtube.com/watch?v=G9Nz1y7Sj74

Sad to see the quality of the content from Lumafield slowly going down. Feels like the content got less technical after they moved it from "scan of the month" to their blog, and now it feels like the descriptions are just slop, not matching the scans themselves.

Examples:

- Each window is sealed under a thin polymer layer, balancing optical clarity with biocompatibility while preserving the ring’s continuous, scratch-resistant exterior. <- they're on the interior of the ring, and I'm assuming if they're polymer, they're not very scratch resistant.

- This flexible board architecture allows the Oura Ring to maintain its circular form as well as distribute heat [...] <- what heat? And how?

- The charging coil runs along the ring’s outer circumference [...] <- scan shows a small coil on the inside, not running along the circumference

- [...] we can easily visualize the deployment channel and insertion mechanism that guide this filament to its precise depth and angle. <- I can't see the insertion mechanism.

- spiral geometry <- the Bluetooth antenna isn't spiral. Nor does it communicate "through the user's skin"?

- miniature microphones (visible as small cylindrical cavities) <- they're rectangular.

Even discarding the factual contents the sentences appear to be AI.

But especially nonsense like ”allows the Oura Ring to maintain its circular form as well as distribute heat” is what you get when you RLHF your chat bot for lazy students cheating on homework.

Also I'm doubtful that the needle in the CGM penetrates only "the top skin layer" given that it was around 1 cm long.

It blows my mind they used AI to generate a couple paragraphs worth of rather nonsensical text. It would've taken them about as much time to just write something sensible by hand.

mikeselectricstuff on YouTube did a teardown on the Omnipod wearable pump a while back, very cool mechanism.

https://www.youtube.com/watch?v=e2MQUUkubgs

Insulin is incredibly potent and can easily result in life-altering if not fatal consequences at relatively low ratios of the therapeutic dose, so these things need to be dialed in and extremely reliable.

YouTube teardowns from knowledgeable engineers are a gold mine for learning how real world products are engineered. I always recommend these for early career hardware students and engineers.

What's so wild (and a little disheartening) is that the omnipod is a disposable device. Use it for several days, and throw it out.

This is an extreme corner of quality/cost/reliability optimization. The delivery mechanism has to be extremely repeatable and reliable, it has to fail in safe ways, but at the same time, it has to be cheap enough to throw away.

Durable pumps are all made with very expensive precision mechanisms, lots of metal and high quality plastic.

A friend's coworker had their pump lock on, and inject the entire reservoir of insulin into them. They were discovered in their home by the police after family members lost contact. No idea if it was an Omnipod, but I would hope that all insulin pumps have a separate watchdog circuit to prevent this.

Did they survive?

Presumably no, but the comment is unclear - the police could have found them unconscious, although it is mostly likely they were found dead.

My wife is T1 diabetic and has the Tslim pump. When there is an occlusion at the infusion site insulin stops being delivered and blood glucose goes high.

It never occurred to me that a pump might fail in a way to give her too much insulin...

My daughter is T1 as well. This bothers me every time I think about it. You are probably already aware but if your wife is using the dexcom there’s an app called follow that she can add you to to get alerts if things go awry (highs or lows).

She probably won’t want to use it but if she worries about that at all it might provide some peace of mind.

Sadly no. They were found unconscious, then taken to the hospital where the doctors determined that brain death had occurred.

While I don't have diabetes, I will be getting an advance directive made. This was horrifying.

https://en.wikipedia.org/wiki/Advance_healthcare_directive

I know people from Lumafield read these comments occasionally, and I'm grateful for all of this!

Why is the Omnipod available[0] to explore in Voyager, but the Dexcom is not? I'd like to send links to both for my diabetic girlfriend to enjoy, who uses those two particular devices.

0: https://voyager.lumafield.com/project/16d13f1d-58f5-4572-b2a...

Great images, OK writeup. There are some bits of bullshit, like "The proximity of microphones to processing hardware minimizes latency". No, the speed of electrical signal propagation (around 2/3 the speed of light) is not significant for microphone placement.

It's AI slop. The descriptions are all meaninglessly specific like that, saying things that are technically true but don't make sense to point out.

It's sad to see such waste with the Dexcom. A sizeable, single-use coin cell with a total useful life of 15 days, after which the entire unit is discarded.

And it's a bitch to open to harvest the cell, as well. You have to break it open with a fair bit of hassle.

It's always interesting to see how are things build in the Lumafields "Scan of the month". The the most interesting scan from Lumafield I saw was not a Scan of the month, but in "Adam Savage’s Tested: Surprising Flaws in 18650 Lithium-Ion Batteries" [1]

[1] https://www.youtube.com/watch?v=-Y23nfAOiXQ

PS: Nice company logo btw. ;)

Glad they're still doing these. I really enjoyed Scan of the Month and then they just stopped doing new scans after the Moka Pot.

Really love these scans! I would love to have on of these at home, just to tinker with devices and understand how they work. Then I usually want to check the price, see "Talk to sales" an decide probably not the price range that is good for private use. Nonetheless, great articles and an amazing device.

I’m sure there’s the small issue of radiological safety as well. Obviously one can be trained to not fry yourself with x-rays, but I wouldn’t, say, pick one up off Aliexpress and have at it.

Some of their earlier videos go into a lot of detail on the safety interlocks (including that the radiation near the device can be lower than ambient because it's basically a large chunk of shielding :-)

As for pricing, https://news.ycombinator.com/item?id=45392896 had some numbers from 5 months ago. It seems like the kind of thing that you'd want as a nearby service, unless you needed to do continuous inspection (they have some automated conveyor sampling products too, it looks like.) My last company had a few 3d-printed components that would have been interesting to spot check after wear testing, but for a lot of things, the competition for the scan is "open it up with a screwdriver" :-)

I bet it's something you can lease with a traceable calibration certificate.

The custom Lipo battery with thermal effects and weight considered is really beautiful to see. I've been curious about custom Lipo battery shapes for rings because my fingers get cold when I wear rings. Would a battery heating up just a bit help make that comfortable for me?

Would a battery heating up just a bit help make that comfortable for me?

In something ring-sized? Maybe for about five minutes, and then the battery dies. (I assume you mean using resistive elements to create heat; heating the actual battery seems like a bad idea.)

My bad, I read the article wrong, they are only concerned with thermal heating while it's charging. I did seem unexpected that a ring could heat up enough to be a concern while being worn.

> my fingers get cold when I wear rings

Unless the ring is shaped as a heatsink/radiator, I imagine it would eventually get into equilibrium, and you wouldn't feel the heat-flux.

Is it possible that the "coldness" comes from its indirect affect on blood-circulation?

Yes I think you are right and also fingers tend to swell and shrink with heat and cold so the ring that fits nicely in a cooler room will restrict circulation slightly once I'm feeling warmer, leaving me with one cold ring wearing finger.

A battery. Which can catch fire. Around your finger?

Phones catch fire and men tend to stick them in the front pant pocket. But yes true, so far I haven't gotten into smart jewelry. I was pretty into jewelry for a while but never rings because of the cold finger situation. Necklaces can be problematic too. I chipped my front tooth slightly when I jumped wearing a big crystal and smacked myself in the face with it.

These are largely somewhat pretty but ultimate unrepairable e-waste.

San Diego is really a hub for health wearables! Tijuana to an extent too.

Oura - based in SD.

Dexcomm - based in SD.

Omnipod/Insulet - major R&D hub in SD & TJ.

Oura is headquartered in Oulu Finland and the main US office is in SF.

San Diego does have a bunch of health tech, but it pales in comparison to Boston.

> San Diego does have a bunch of health tech, but it pales in comparison to Boston.

I don't have firm data on this, but colloquially among medical people, San Diego is seen to have more biotech startups than any other metro, including Boston/SF.

Boston has more research, of course, though SD is competitive there as well.

We can disagree about numbers etc, but 'pales' doesn't reflect reality.

edit: https://www.cbre.com/insights/local-response/global-life-sci... -- support for it being an important life science market

I have worked in tech in many different cities and when I worked for a startup in San Diego, we were surrounded by health tech companies of all sizes. I've never worked in Boston, but I would say San Diego is definitely a health tech hub.

Is it just me or did the tonality in this one change towards an infomercial?

Could be, the company behind the website would like to sell you an industrial CT scanner.

They always were supposed to be for marketing, but I did like their in-depth technical analysis. I imagine that took a lot of work/time to write up though. I'm okay with them skipping that sometimes to get more public scans out for me to enjoy. But I also would love their analysis as well!

One thing I really enjoyed about the analysis was how it really explained the nuance of the technology they sell, and there were always lessons in it for how to tweak the machines on different objects/materials, and how to interpret things, and why certain areas looked the way they did.

For example, on the Omnipod[0], why can't I find an attenuation window to see how much medicine is left inside the reservoir? Is it empty? Is the medicine too low in attenuation to be seen? Is the medicine too similar in attenuation to the outer casing to isolate from it? Could it be isolated if the machine were set up / configured with different settings, and if so, what are the tradeoffs?

0: https://voyager.lumafield.com/project/16d13f1d-58f5-4572-b2a...

still not into scroll-jacking, but these breakdowns were well-written and documented.

I dont want CT scans of wearables. I want wearables that can do CT scans.

well, maybe wearables that provide some sort of internal visual scans. But with CT scans delivering 70 times the radiation of a typical x-ray, I think I'd prefer not wearing a portable chernobyl.

Maybe a wearable ultrasound instead?

edit: after a little informal side-searching after posting this, I've learned that people working at Chernobyl, not in the reactor directly, but elsewhere in the sprawling site received anywhere from 1 to 100 CT scans worth of radiation. The firefighters that were on the roof received anywhere from 100 to 1,600 CT scans worth of radiation.

> Maybe a wearable ultrasound instead?

If one is concerned about the potentially damaging effects of radiation, and the relative safety of ultrasound technology springs to mind, then one may be also interested in reading more about the apparently forbidden topic of ultrasound safety studies, if such a person can get past the cognitive dissonance from having been told the consensus opinion on how safe ultrasound is, e.g.:

https://www.amazon.com/Studies-Conducted-Indicate-Prenatal-U...

https://www.westonaprice.org/book-reviews/50-human-studies-j...

http://whale.to/c/50_human_studies.html

https://harvoa.substack.com/p/dbr

The jury may still be out?

All of those links are for the same book from 2015 (the fourth isn't direct to the relevant article but it's easy to find on the page). Has there been any new information since then?

The 50 studies in the cited 2015 book ought to span a range of time, and their keywords could be used to search literature for more recent material.

> Has there been any new information since then?

Since you asked, there apparently was a 2017 followup book by the same author. These links are for that book:

https://harvoa.org/chs/pr/dusbk2.htm

https://www.amazon.com/Ultrasound-Causation-Microcephaly-Vir...

https://www.goodreads.com/book/show/36466945-ultrasound-caus...

That book claims:

> Microcephaly incidence increased 1000x within the area of The Network. This was first observed seven months after The Network began its remote prenatal ultrasound program. Do the math.

Almost every baby is exposed to prenatal ultrasound. What do you think was different about that ultrasound program? Why would prenatal ultrasound cause microencephaly there, but not everywhere?

> not everywhere?

Are you absolutely certain that there is not an unexplained uptick in brain damaged newborns/children in the USA?

And that its cause is not some thing(s) that "almost every" one of them is subjected to repeatedly?

And that it is not just a case of better/more/over diagnosis?

IDK about by you, but there are literal nurseries/schools for the brain-damaged kids popping up on Main Street. That's how many there seem to be.

So yeah, maybe they're not in that study. But that means they don't exist?

I don't think that's comparable to what happened in Brazil at that time.

I personally prefer to approach the topic of "safety" by considering the trade-offs. The knowledge gained through ultrasound significantly outweighs potential risks associated with it.

People still continue to play the lotto thinking they will win, and they reject statistically low risks in lieu of a greater risk created by avoidance. See: any vaccination topic.

When shifting into the topic of a wearable though, the extreme amount of time alone amplifies the risks into outright dangerous levels. I did not seriously believe ultrasound to be safe to that level.

> a wearable though, the extreme amount of time alone amplifies the risks

The time, and also the proximity.

As I understand it, the potential dangers of a lot of these kinds of things dissipate quite rapidly with distance.

But with wearables, the emitters are quite literally strapped against the body (practically zero distance).

That is not even close to feasible with today's level of technology, and will not be for quite some time.

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