The 12V solenoids have arrived and are operable from my current setup! I've written an arduino code in which the solenoid opens only when a voltage input passes a certain threshold. This means that, when the pressure sensor arrives, the system can be set up such that the voltage output from the sensor can operate the solenoid.

We are also trying to determine whether we can operate multiple arduino shields running different codes from the same arduino UNO board. Both shields use pins in common, so it may not be possible to run code to both at once. Does anyone know whether it might be possible to run two different codes to the shields, if it is done not simultaneously? For example, a code could be run to one shield to open the solenoid, then immediately after, another code could be run to the other shield (which operates a vacuum pump) to pump gas into the chamber? Any thoughts would be appreciated!