In the loop() we check to see if the water level has reached any sensor and if so then turn an the corresponding led. We also use the LCD to display HIGH if the water has reached the highest poing, ...

The device is built around a cheap 1/2″ brass water flow rate sensor connected to his shower hose, which outputs pulses as a small wheel passes an internal hall effect sensor.

We’ve seen several water flow measurement systems for home use, such as this neat ESP8266-based shower water monitor. If you prefer just a simple visual reminder to turn off the tap, have a look ...