Tank level monitoring

[affinite]

Thanks for pointing out these inductive sensors, It's nice to find such an economical way forward with tank monitoring. I thought I could get a small number of them going with the GPIO and Actions tabs in Openplotter but that hasn't really worked out and I'll have to see what I can do with your code.

They don't work on my aluminum tank of diesel, as we suspected. I have been wondering about a circuit to measure the resistance on the existing tank sending unit using the ADC chip already implemented. The catch is I think we need to disconnect the existing gauge momentarily to take the measurement. There must be a simple circuit that could do that periodically; once every 10 minutes would be more than sufficient. And I suppose on the software side we'd need to report the highest reading in 10 minutes instead of a realtime measure.

Nice that my work can be of benefit.

Have you tried to measure voltages etc on the terminals on the existing gauge ? They are normally a variable resistor and if so the voltage at the output might correspond more less linearly with filling. The analog input terminal is high input impedance so connecting this to the output should represent no problem. Then some calibration work need to be done.  Try it out with a multimeter first and figure out what's going on, then connecting it to OpenPlotter should be easy. Just think of isolation and common GND etc. 

Ole

Please report any success on the resistive sender front so I can shamelessly copy it !
I have been trying to accurately read a tank level/voltage using existing resistive fuel sender. 
In my case the old fuel gauge is broken so Ive setup a voltage divider using the 190 Ohm tank sender but my biggest problem seems to be getting a steady reference voltage to start with. 
Of course the boats 12v supply isn't very well regulated and even when I used a 10v regulator chip to supply the sender, that too seemed to suffer from variable loads. 
(My fuel, water and waste tanks are all metal so I actually have 3 resistive tank senders on this regulated supply and I guess that might be the cause)
All the best 
Steve