We are in the digital age and a digital pregnancy test should be least surprising thing. It looks like a regular pregnancy test, save for the tiny LCD screen. However, someone was curious to find what makes it work and it is interesting.
A Twitter user by the name @Foone decided to take apart a digital pregnancy test kit by Equate. The user is a self admitted collector of weird old computer junk so this was right on brand. When Foone was able to pry open the digital pregnancy kid, he found an interesting layout.
So, with it open, we've got a single PCB here.
There's some kind of pill-looking thing to the left, a little LCD screen, and a I can see a battery on the other side. pic.twitter.com/WsuPI3pVsb
— foone (@Foone) September 4, 2020
The unit boasts a motherboard, the LCD and a CMOS battery at the front. At the back, there is the battery and a paper strip used for trapping the urine. The paper used is apparently the same one that is on traditional ‘analogue’ pregnancy tests that shows lines.
Foone also noticed how the device works. When the wick gets wet, it conducts electricity and the device turns on. There are three LEDs and two photosensors that do the ‘sensing’. Foone figured out that the snsors measure the light hitting the two sensors so that they can detect lines on the paper. The whole point of the system is to read the lines and tell you that you are pregnant or not pregnant instead of the single or double lines.
The Holtek HT48C06 chip inside the pregnancy kit is interesting. There is an 8bit microcrontroller, 64 bytes of RAM and runs between 4mhz or 8Mhz. This won’t break any records. Apparently this CPU is more powerful than the CPU used on the original IBM PC that was released in 1981.