A hacker has uncovered a fancy digital pregnancy stick that is just a glorified analogue paper test strip with a screen added, a novel form of activation, and a big price tag.
Hardware hacker (and floppy disc 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? pic.twitter.com/eEDHRzSyY7
— foone (@Foone) 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.
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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 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) 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.
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. ®