555 general purpose

Needed some pcbs for various 555 DIY minor projects which mainly don't need astable mode. Relay isolation important in many cases. Will cut a track at pin4 Reset, hold reset high with 10k ohm resistor and use gnd and pin4 to detect water level, in a bi-stable mode, where pin2 via switch (PB momentary) will trigger relay to drive an external water solenoid valve. Water fills an evaporative, portable unit, from a garden hose. When pin4 & gnd detects overflow, solenoid will close to prevent flood on ground. When the water drops below detection level, pin 4 will once again be eld high to Vcc but will require P.Button switch at pin2 to be pressed to repeat operation. Thanks to the designer of this PCB. I dont have time to relearn Kicad. It is a very neat board.