I'm trying to build a simple low-power water level alarm such that it could run continuously for at least 4 months on just 3x AA batteries. I've found this schematic which uses the 555 timer:
However, the 555 timer has a minimum power consumption of around 30mW, which would be too much. Would it be a good idea to modify the circuit such that the water's conduction supplies power to the 555 like so:
Is water conductive enough for this to operate?
Would it be a better idea to just use a low-power MCU like MSP430 and raise an interrupt when the probes short by water's conduction?
Any thought appreciated.