I am seeking to have you design/build a water level sensing circuit with electrodes. This small device is intended to replace 4 float switches we are now using with a lower cost and higher reliability solution.
The concept is that this device will have 5 electrodes in the water tank:
High is the shortest electrode; Ground is the longest electrode.
“Electrodes” to be simply… a flat 5-comductor ribbon cable, with each conductor trimmed the desired lengths.
TIMED: A high-current mechanical recycle timer starts/stops the pump to pump water out when the “Timed” level is reached. When this level is reached it triggers the mechanical timer to run based on the timer’s on/off settings. Timer trigger is very flexible: AC/DC 12-240V consumption is 3 watts. Timer relay contacts handle 1/2HP pump @ 120VAC 60Hz.
OFF: At this level a circuit opens the High and Timer circuits to protect the pump from dry-running.
ALARM: At this level a circuit goes high to sound a low voltage (12VDC), low current alarm.
HIGH: At this level a circuit will start the pump by bypassing the timer contacts. This is redundancy in case the timer goes bad. This circuit needs to handle 1/2HP pump @ 120VAC 60Hz.
My price goal for the described device is to be <USD40 in small quantity…
Attached are sample circuits that can be used for concept purposes.