The Arduino UNO and GPS shield logs the coordinates by the use of the trigger inputs. The trigger takes +ve 5 to 15v on a pin. (See Image 1) It is designed to be used to log, each time a solenoid valve(s) operates in the circuit in image 2.
How do i safely integrate this trigger/logging circuit into the circuit in Image 2 and protect the logging circuit? Which components do i require and at what points should i install them?