I need to build a simple delay off timer. When the input is triggered (pulse only) the output must go high and stay high for a period of say 1 hour or 4 hours or selectable. When the input is triggered again, the output timing is restarted.
Any idea's? Would a 555 timer work? Not sure about the long delays.
Supply is 24Vdc.
Yes, the 555 would work. The time delay required is rather high, though. That means you have to use a good quality cap. The CMOS version of the 555 would be more suitable.
You will also need a regulator, since the supply voltage is 24V and the 555 cannot work at that voltage.