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Pls i need advice on a suitable sensor to detect if a door has been locked from outside? Answered

What i have seen around is basically to detect if a door has been locked. But i need a system in which a microcontroller would receive a signal only if the door has been locked from outside (only one side). Would really appreciate your help.

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user
rickharris (author)2014-12-18

It may be easier to detect if the key is close by (RFID) AND the door is locked.

IF the key hangs by the door over an RFID detector AND the door is locked then your inside .

IF the door is locked BUT the Key is not detected then the door was locked from the outside and the key removed.

You could detect the locked door with something as simple as a microswitch on the latch bolt.

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user
iceng (author)2014-12-17

This $8 sensor can do it.

But you cant Lurk and make it work.

Goto answer....

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user
seandogue (author)2014-12-17

Where have you seen around?

And why do you need such a device? Frankly, it sounds a bit questionable to me.

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steveastrouk (author)2014-12-17
user
iceng (author)2014-12-17

First need to know if in can be locked from the inside too ?

And is the outside lock a physical key ?

I am asking if the lock is a tumbler key lock ?

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