Here is a tested Arduino project that uses 3 sensor probes as water level indicator with 3 leds and one LCD display + a simple controller that turns on a motor when the water has reached the desired ...

When the sensor detects that the moisture content is already below 30%, it sends a signal to the Arduino, which, in turn, activates a water pump to provide hydration to the plant.

There are a flame sensor and a water pump up forward, as well. You can probably guess, the device notices a flame and rushes to squirt water on it. That got us thinking, though.

And the third, tells it what type of trigger to look for, a logic high, a logic low or a transition between the two. You can find detailed articles/tutorials on Arduino Interrupts (prepared by me) ...

I've just come across a no-name non-contact, high-precision 80 GHz mmWave radar sensor for liquid level detection with a 40m ...