3.8v

 

3.8v

And that is only driving the LED2 circuit.
3.8 volts indicates the resistance of the probe in the water is appx 31.5K ohms.
That's close to what I read using tap water with an ohmmeter.
Are the probes nice and clean?
Maybe connect terminal #1 of both probes to the 7.2 volt battery source.

 

That was it, dirty probes. I gave all four ends of the wires a fresh coat of solder and it works fine.

As part of maintenance will have to touch the ends up once in while.

In the meantime I'm figuring how to get the schematic right so I can arrange a PCB.

 

Updated schematic:

 

Thanks. Here is mine. I still have R7 & R8 in place. I added 2 pin connections where the battery connects, where SW1/2 connect and for the probes. It should bring over pads for those points to the PCB I think. Pretty sure I have footprints in place, might have to change them for C1/2. For some reason the ERC said PWR-Flags were needed.

I ran the ERC and there are no errors.



This seem OK to you?

 

Even better. I like it.

 

Should try removing R7/R8 and see what happens?

 

Should try removing R7/R8 and see what happens?

You can but would recommend leaving them in.

 

Reason I asked is yours does not show them. OK leaving them in.

 

That was the original circuit when adding the LEDs but favor leaving them in.