The idea for that project came up after Olha and Dmitry moved to a new flat and acquired 7 different plants - each with their own water and light needs, placed in different locations.
Touching each pot repeatedly in order to determine whether it's time for watering is just too much to ask from an engineer - so here we are.
It's not like there are no such solutions at all - but some of them are too simple (and require replacing batteries, which isn't exactly what we want to do), some are just too expensive to buy a set that covers all plants (in fact, some good units are so expensive that probably the whole process of multiple prototypes production till we reach our ultimate goal would cost less than buying a required set).
Anyway, we started with the simplest unit possible - but since Kseniia and Lucy dived into advanced hydroponics, probably we'll make a more advanced version later
We came up with a simple and rather generic PCB design, produced a prototype set - and assembled one to test the whole concept. We never dealt with this kind of sensors before, so most likely we'll change a lot as we go - possibly the whole approach - but the first step was made.
Unfortunately we didn't have soldering paste at hand, so had to put solder on each pad, then cover them with flux again, and then place components - even without paste, hotplate is still more convenient than soldering them one by one.