As a student, I've noticed that practically all of the dormitories in my university require residents to tap their student cards to a sensor before they are allowed to enter their building. (Moreover, some buildings even use electronic room keys, but it seems (to my non-Jewish mind) that the situation for that specifically might be covered by something like this.)
Am I right in assuming that taking such an action would be forbidden on Shabbat, since it involves manipulation of electronic devices? If so, have any recommendations been made for such situations (particularly since it doesn't sound like a good idea to simply wait outside for a Gentile to unlock the door in the dead of winter)?