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 I drain water (water change) I use a ‘U’ tube and even if I am not there it will not drain below that level. A full drain of the tank would need to transfer the fish to another tank.

Arduino Uno. 4-channel relay module. PIR motion sensor. Steps: Use Arduino to handle sensor input and relay control. Pi runs a Python Flask server with a simple UI to toggle GPIO pins via serial ...