Expensive pregnancy testing sticks turn out to have very analogue internals when it comes to getting results
- Reference: 1599310867
- News link: https://www.theregister.co.uk/2020/09/05/digital_pregnancy_testing/
- Source link:
Hardware hacker (and floppy disc [1]enthusiast ) foone bought a pack of two digital pregnancy sticks for $7, whereas a pack of 25 paper-based ones costs about $9. Foone decided to pry into one of the sticks and revealed it had a Holtek HT48C06 processor with 64 bytes of RAM, an 8-bit microcontroller, a series of LED lights, photosensors, a cell battery, and a small rectangular screen.
The computer onboard makes it seem quite advanced and high-tech, but at the core of is, well, one of those cheap paper tests.
And check it out: this paper strip has a line on it... this is a pregnancy test strip, isn't it? [2]pic.twitter.com/eEDHRzSyY7 — foone (@Foone) [3]September 4, 2020
None of the hardware or software is used to detect if someone is pregnant or not. That job is for the paper, which looks for human chorionic gonadotropin, a type of hormone secreted during the early stages of pregnancy, in urine.
Amazing peer-reviewed AI bots that predict premature births were too good to be true: Flawed testing bumped accuracy from 50% to 90%+ [4]READ MORE
The whole device is activated when the strip is moistened. The damp paper connects a switch that fires up the stick's battery and, if the characteristic two lines show up, the LED lights and photosensors spot this and the screen displays the results - "Pregnant" or "Not pregnant".
“I was kind of surprised as I figured it'd be integrated somehow, rather than having a separate test paper in it,” foone told The Register . “It seems if they were going to use standard test paper, they'd make it reusable by having you insert your own standard test strips, since those are so cheap.”
At first foone thought it was a “100 percent a marketing trick”, but now believes their “their benefits [have been] exaggerated somewhat.” As some Twitter users pointed out, in some cases the digital stick is a better option for those that might have impaired eyesight.
You can solve all these problems with a simple LED and a photodetector.
It’s sensitive
It’s reproducible
It’s not biased
It can be used for quantitative analysis.
It obviously depending on how good the detector is. But usually is way better than naked eye. — Vittorio Saggiomo (@V_Saggiomo) [5]September 4, 2020
“During the thread someone brought up that they have to be FDA certified, so it makes sense now. It's easier for [companies] to integrate an existing test strip rather than developing something new they'd have to get certified,” foone added.
The next stage was to see if this could be beefed up a little. After adding a new processor and screen foone turned the device into kit that could broadcast messages no one wants to see.
[6]
This is going to be an awkward chat. Click to enlarge
The moral of the story: if you you're trying to get pregnant, or not, the old ways are sometimes the best, or at least much cheaper. ®
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[1] https://twitter.com/Foone/status/1025778067858321408
[2] https://t.co/eEDHRzSyY7
[3] https://twitter.com/Foone/status/1301708708649394176?ref_src=twsrc%5Etfw
[4] https://www.theregister.com/2020/01/24/ai_models_data/
[5] https://twitter.com/V_Saggiomo/status/1301810809329389574?ref_src=twsrc%5Etfw
[6] https://regmedia.co.uk/2020/09/05/pregnancy.jpg
[7] https://whitepapers.theregister.com/
Click to enlarge?
Isn't that what got us into this mess in the first place?
Wastful - but unfortunaltly not uncommon
Having a chemical test get interpreted by electronics using an optical sensor is not uncommon. A well calibrated system is considerably more deterministic than even the best trained human using a Mk I eyeball. So I am not in the slightest bit upset about using electronics to 'read' a chemical test strip (regardless of how easy it would be to do so)
What is annoying is that the electronics are single use.
Surly we can come up with a similar device with replaceable strips?
Looking at the PCB (as an electronics engineer by trade) it looks like the only thing preventing that from happening is that the mechanical design would need changing to allow strips to be replaced. Other than the fact you are going to pee on it, a simple slot on the end would be enough. Realistically this would need a transparent plastic over the optics (LEDs and LDTs by the look of things), I doubt that this would cost much more than a single additional plastic part, enabling the electronics to remain sealed against moisture ingress whilst still providing no external light path to the sensor area. The battery is probably good for several months without improving the electronics, so really there is nothing much else to do.
Indeed I suspect that the original engineering would have been this sort of design.
The real problem is that if you sell 1 reusable 'reader' and a set of test strips you don't make the same amount of profit, no matter where you sit in the supply chain...
"Surly we can come up with a similar device with replaceable strips?"
I understand your annoyance, but there is no need to get all surly about the waste. Please, can't we at least maintain a good humor while commenting. Shirley that is not too much to ask.
"It's not yours"
That's one hell of a thing to tell the woman who has just done the test...
Re: "It's not yours"
Alien abduction and implant. Or, invitro fertilisation and the lab got the eggs mixed up.
This device is far less unreasonable than it seems.
LFDs (lateral flow devices - the paper strip used in this test) are simple in theory, but get a human being involved and what *should* be simple and clear becomes variable, vague and uncertain. In most cases where there's a pregnancy then a nice clear line will develop, but sometimes it can be faint, or sometimes people will see a positive reaction where there isn't one. Attaching a simple detector with a pre-determined threshold (possibly matched to the batch of components used to create the LFD) will remove the uncontrolled human factor and will provide a more reliable result.
FWIW I've had a little input into developing LFDs for other uses, and they can be a challenge for everyone to read. Lab coat obviously, because who'd risk spilling someone else's wee on their clothes?
Low tech is too old tech
The moral of the story: if you you're trying to get pregnant, or not, the old ways are sometimes the best, or at least much cheaper.
At least environmentally it is a real kicker. Plastics and electronics are nicely poor on the scale of environmentally sound . The trend of the time is to secure your as-yet-unborn child with a good head start at a large environmental footprint. And also, please make sure that the as-yet-unborn child is getting used to high tech requirements of modern times. Low tech is only for old people.
(I heard that a smartphone for prenatal use is in the makes; implantable and complete with gaming and xflix subscriptions, including ads for the unborn child)