https://www.instructables.com/Adjustable-Timer-Switch/
Adjustable 555 Timer Relay Switch | Monostable Multivibrator Circuit : 7 Steps - Instructables
Adjustable 555 Timer Relay Switch | Monostable Multivibrator Circuit : Learn how to make a precisely adjustable timer with a variable delay from 1 - 100...
timer relaymonostable multivibratoradjustableswitch