The design of the usual things. Switch in the hotel room.

The solution in one of the hotels in Pittsburgh. In order to earn electricity, you must insert the key (it is the key to the front door). According to the owners of the hotel, the system paid for itself in 3 months. Now the problem has been solved not only on energy conservation (air conditioners left, turned on, heaters, light bulbs, etc.), but also the problem of finding the room key in the morning (very important for the morning of our tourist :)

It is not entirely clear what is with the refrigerator, but I think that it is powered from an ordinary outlet that is not included in the system.
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Who is interested in new solutions for the usual things, see also:
UI packs of milk
UI packs of pills

Not looking at the fact that this system is not new (and it was not stated in the post), the discussion turned into an interesting perspective - “my story with this thing and how I (un) deceived it”. Stay positive!