I have added a very small 5V to 12V up converter to power the sensor from the Pi and a resistor voltage step down network to bring the output back to 3.3v

When the NPN sensor ‘sits’ above the metal plate on the 1-liter pointer and the LED on the sensor is lit, how high can you lift the sensor before the LED goes out? If this is ‘very little’ you could have a sensor sensitivity problem. If you open a water tap and let it flow, what does the LED show in ...

I used a different approach, I ordered a very small 5V to 12V up-convertor to power the inductive sensor with 12V from the RPI and a resistor divider of 10k and 3k9 to convert the 12V back to 3.3V for my RPI-Zero-W GPIO pin 21. The sensor signal is very stable and all worked instantly. I soldered ...