I have a GPS unit which I'm mounting in the trunk of my car powered by the 12v lighter plug in the trunk. The socket has power only when the key is on and the GPS unit requires its power button to be held down for 1 second to activate it. If I were to use the 555 monostable circuit I found (link below) to trigger a relay that would act as a remote switch, would I be able to omit the circuit's pushbutton and just use the lighter plug's power to start the countdown? Also, it seems as though there is a 6 second delay built in to the circuit, what component values would I need to change to get the 1 second delay I need?
555 timer Mono stable (one shot) circuit- posted
18 years ago