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

Sure, modern paper shredders already have sensors that tell you when the bin is full, but if your machine lacks this feature, you can just build it a custom sensor with an Arduino Uno.

While PIR sensors can be used with Arduino and other microcontroller boards, those best-suited for hobby use are smart enough to perform simple tasks without any programming.

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.

If the water is somewhat low, the Arduino-controlled relay powering the tree is switched off and then on again, every 5 seconds. If the base is nearly dry, the tree asks for water by blinking the ...

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.

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 ...