Just a simple schmitt trigger latch mechanism driven by a comparator. The switch represents two metal plates, and when you short them out with your fingers the comparator will enable the schmitt trigger and the two relays that control the door motor, for about 8s. The time can be varied through the 47uF or the 1Mohm resistor. The schmitt trigger delay circuit is the equivalent of a monostable multivibrator, and they're interchangeable, as you see fit. I used two relays because most of the power relays require high power to trigger them, and a low voltage relay is ideal for this instead of a transistor switch.
