Hi! Im trying to figure out why my inductive sensor is not being registered. Its an npn sensor running 12v from the power input on the board with the regular voltage divider via resistors. When messuring on the signal wire ive got 4.8v which should be fine i guess? The weird thing is that running M119 shows the same state no matter the position of the sensor. Open/triggered depending on the invert setting in config.h . When messuring the signal pin on the board that too is giving me 5v. Should it really be doing that? I am completly lost 
Does it show 4.8V at any time or only when it is really triggered (close to the printbed)? By default I guess it should be Low Signal to trigger (bridge between GND und Signal) and High Signal for “open” (5V).
With the sensor off the board, what voltages do you get on the signal wire with and without metal in front of the sensor?
Are you following:
http://3dprint.wiki/reprap/anet/a8/improvement/autobedleveling
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First tip i can give is Check it unmounted and wit nothing around. Maybe the cause is it detect the extruder, rods, tc
Hi again everyone. Thank you so much for all your answers!!
I managed to sort it out yesterday and i tought i would share my experience here if someone else is doing the same mistakes.
As i said i was using a voltage divider circut using 2 resistors in the 1.5x range from eachother. But i took some spares that i had at home that gave me a total impendence of nearly 2MegaOhms… From what i understand (and i know very little about electronics in this aspect, so please correct me if i’m wrong) that was to much for the 5v signal coming form the mainboard to go through to get ground.
My solution was removing the voltage divider and instead using a diod. the diod was reversed so that the 12volts from my sensor was blocked by the diode, not frying my mainboard. but when the 12v vanished (sensor was close to metal) the 5 volts from mainboard was able to pass right through the diode and reach ground.
Everything is working as intended now (except needing a bit more calibration to get a good height for the nozzle!)
Thanks again!
