Greenhouse Watering

The interesting part of this one is not the watering, it is the refusing. A capacitive probe reads high when dry, so the percentage is inverted and clamped. When the soil drops below the target the pump runs - for eight seconds, and then it waits fifteen minutes whatever the probe says. A sensor that has fallen out of the pot reads bone dry forever, and that limit is the difference between a watered plant and an empty reservoir on the floor. No I2C parts at all: an analog input, a digital output and some arithmetic. That is the shape of design MicroPython suits, and you can change the watering time from the REPL between runs without rebuilding anything.