Hear us out: Smartphone lidar can test blood, milk Could the light detection and ranging (lidar) sensors in your future smartphone take the place of laboratory equipment in health and food safety applications? It's looking like a possibility. Researchers at the University of Washington reckon handset lidar can determine fluid properties, sparing you from having to use …
Yes - not sure if the paper is peer reviewed yet but, as you say, enough detail that anyone can have a go at it.
Even if it can't be done practically/commercially with just a phone, a new testing device that only needs a drop rather than a test tube full and can be built with COTS sensors is still quite a breakthrough.
"... a pint?! Why, that's very nearly an armful!"
Right, but it's the same kind of development: you add new kinds of sensors while refining the existing ones. If you're lucky the results are "greater than the sum of the parts".
The point is the parts required are available on any Shenzhen market, when they reopen that is!
The paper says they have used 'the type of sensors' used in phone lidar, not that they have used your iPhone.
Then it gets spun by the university publicity office, and the conference organizers, and the journal - to get clicks = further funding.
We now use banks of semiconductor lasers in industrial applications but that's a long way from 'DVD players slice through steel'
"Think of it like the early days of Time Team as they went from metal detectors to radar and then lidar."
I was thinking along similar lines, but the ground resistivity measurements. The first ones were a bit of wood with nails hammered through and a rope loop for pulling it back out after stamping it into the ground. We say that device evolve and improve over the course of multiple series going from dot matrix printouts that took hours to process and were a bit rough, to almost live video presentations of the mapping data :-)
Some Theranos technical documents said that AI was being used to create more information from less data; something not possible.
This research measures the LIDAR sparkle in milk caused by solids to see if it matches expected values. It measures the LIDAR phase shift in blood to see if it matches expected values. It's completely within the realm of matching known science and it doesn't violate any data theory. The only difficult part is the application of the technology to real-world environments.
Claiming to know the taste of milk from LIDAR would be a VC funding scam. Claiming the same for blood probably means they don't care much for sunlight and garlic.
My experience is with using LIDAR with modulated visible range lasers to evaluate heat damage in composite materials used in aircraft. I'm an engineer and worded on the data acquisition and coding, not one of the scientists, but I can tell you that special sensors, either PMTs or "silicon PMTs", which are arrays of avalanche photodiodes, were needed to measure the tiny signal gathered from the back-scattered light. These have a gain of between 10^6 - 10^8, whereas the gain on the photodiodes used in a phone's CMOS sensor(s) have a gain of between 10*2 and 10^3. The analytical chemist said that the SNR would be far too small if photodiodes were used. Just saying.
On the other hand, you can now legitimately fit them to sharks.
Educate me: what's the function of the Lidar on the iPhone? From what I have read, it seems to be there to enable better augmented reality games, which seems a little frivolous - unless, of course, you're an AR games maker.
Also, some are claiming small amounts of data can be sent via Line-of-Sight (LoS) in open air at great distances. I'll never find it, but I read an article that someone did have a working proof of concept for LoS, but it was something around 3 bytes (technically enough to do something with, but not enough to rule out noise).
I'm almost afraid to say this, but my "memory" says there were a few very excited articles about how facial recognition was now going to be less prone to spoofing. The idea was that the phone could use lidar to make a low resolution 3-D map of your face, and verify that to unlock.
Maybe I was having a particularly vivid nightmare?
The iPhone has been making a 3D map of faces (using an infrared dot projector) ever since the first generation of Face ID without needing LIDAR.
The LIDAR on iPhones is lower resolution but longer range than the Face ID sensor - it is designed to solve a different problem. Its also on the back side of the phone, so wouldn't be too useful for unlocking with your own face.
it allows for a scan of as-built conditions and create point cloud of products on racks. That we then use for model mock ups to evaluate warehouse and sales location conditions. Much faster for the forecasting work, and has enabled us to turn around the preparation work from weeks to days. Walking through with the phone makes this a mobile way of use compared to a fixed position unit. Cost is lower, production is faster. We don't need a highly detailed model - this is just for quick checks. 'Walking' around the lidar created model allows us to see stuff that we might have missed if we were taking photos or doing a product count.
Some scam artist managed to convince the Abu Dhabi government that a phone app could detect COVID through "electromagnetic waves".
https://www.weqaya.ae/en/posts/working-of-abu-dhabi-s-ede-covid-19-scanners-explained
It reminds me of those bomb dowsing rods that were literally just radio aerials hooked up to a bulb and a 9V battery.
If this pans out, it will be a great boon to people like me; I have already had so many blood tests, doctors struggle to find a usable vein, my one arm is essentially "empty" 90% of the time, and the other is fast catching up; even counting back of the hand veins.
4-5 attempts at a vein are not uncommon now.
Next stop is using veins in the foot, which I understand is FAR more painful.
[starts humming the tune to "Mr Stabby"]
For all the theranos scam it makes sense for a lot of medical tests. For nondestructive measurements (where you aren't adding a reagent) it's crazy to take blood measure a parameter, throw it away, go to another clinic, take more blood to measure another parameter - just because it's a different insurance billing code.
In my case - in the UK - billing codes are'nt the issue; I have an extremely rare illness, and when suffering a trauma event (like breaking my back 2 weeks ago), they have to take blood samples daily, to make sure I am not about to bleed out.
Simply diagnosing this illness took 6 months of fortnightly blood tests, 6 vials per visit.
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to be fair, you can do that already just by asking them to hold the phone as though they are on a phone call.
if they do that single duplex send/receive thing where they hold the phone flat out in front of their face hole and make noises into effectively the charge port... i think you can see where i'm going there.
no need for an app. some people are just born to be pushed off the train.
See Yue and Katabi, "Liquid Testing with Your Smartphone", CACM 64.10 [Oct 2021]. (Everyone here is an ACM member, right?)
Yue and Katabi used an actual smartphone — an app they wrote running on an iPhone — to perform various tests on liquids by 1) vibrating the container (using the phone's vibrate function) to create wavelets, and 2) imaging the reflections of the wavelets off the bottom of the container (using the camera and light, obviously). That lets them compute the fluid's surface tension to nearly the same precision and accuracy as a lab tensiometer.
With that information, their app was able to do things like detect certain types of water contamination, test albumin concentration in urine, and determine the alcohol content of a beverage.1 Apparently there's some application for that last one.
The paper is worth reading. They had to deal with some interesting problems, and their solutions are intriguing. They also cite some related prior work, of course.
So while this latest work is interesting and potentially useful, and having multiple techniques at hand improves sensitivity and range of applications, it's not the first successful stab at "let's use the existing smartphone sensors to do chemical analysis".
1If you're trying this at home, don't mix up the containers for experiments 2 and 3.
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