About 6 months ago I had this «brilliant» idea that I would like to monitor the water level of my plants living on my balcony. The goal was to keep them healthy and happy (and producing vegetables for me in my urban garden). After looking for a commercial solution to aid me in this project, I discovered that there wasn’t anything out there that would do what I need. The primary reason why nothing worked for me was that none of the products out there are capable of monitoring multiple plants at once, leaving me with the need to buy multiple units. At 10-15 containers for plants, this was immediately recognized as unrealistic, due to their high individual cost. Being the enterprising person I am, my immediate thought was, «I will just build one! How hard can it be?»