Peter Johansson <piclist@mit.edu> wrote:

> The door used RFID access to get from the unsecured area to the secure
> area -- you flashed your card and simply pulled on the door.  But to
> leave the secure area, you simply pushed on the door and it opened --
> one could leave at any time without needing a card.  My first thought
> was that there was a motion sensor on the secure side that unlocked
> the door when someone approached, but I was unable to locate such a
> device. 
> ....
> Does anyone happen to know the mechanism by which this system works? 

Peter:

Motion detectors can be small and unobtrusive... But those doors also 
sometimes use pressure switches under the carpet.

-Andy

=== Andrew Warren - aiw@cypress.com
=== Principal Design Engineer
=== Cypress Semiconductor Corporation
=== (but open to offers)
=== 
=== Opinions expressed above do not
=== necessarily represent those of
=== Cypress Semiconductor Corporation


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