I would take a piece of stout of plastic and fix a nylon tube to the bottom. One end of the tube would be plugged and the other end would be attached to a pressure switch. https://www.allelectronics.com/cgi-bin/category.cgi?category=search&item=PSW-10&type=store
Place the plastic/tubing under a floor mat. When someone steps on the mat it will trigger the switch.
[great idea about the keyboard membrane!]
Imgemini, what's your goal? You sure want to make the floormat? Because, besides the electrical circuitry, there must be some mechanical components in order for the door to open and close - which might hurt you he he he :twisted:
Why sir, you wish poor humble me to provide a simple DC SCR circuit?
Surely a student of telecommunication such as yourself who is familiar with I-Q modulators could post a tutorial on the subject.
I await your efforts sir, and know you wish to please help.