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Door lock sensor

Purpose: Knowing when the room is locked

This is how the sensor is placed in the door frame

Characteristics: The door lock sensor is basically a microswitch placed in a strategic position. It is pressed whenever the lock bolt of the door is extended full scale inside the door frame, which only occurs if the door is locked. The switch is connected in a simple circuit taken from ladyada.net, it is connected to a digital pin on the Arduino. For a proper placement in the doorframe I had to experiment with hot glue attached to the bottom side of the switch to ensure it would not slip more inside the doorframe when the pressure of the door lock bolt was applied.

And it is surprisingly easy to read the switch: Just use digitalRead() to get the current switch state! (In Phatduino automation this switch state is stored in int access_var.)

Pen

 Comments

From: [javascript protected email address]

I was searching exactly for the same product however there no one commercially available one :(
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From: [javascript protected email address]

I am not aware of any commercially available sensor, but there are certainly also other ways to solve this problem. You could use an ultrasonic distance sensor, two conductive brushes that get shorted through the extended door bolt or even a light barrier (exists as single part or you could just build your own). I guess the constraint is space. Why not build your light barrier with SMD components? That seems reliable, cheap and compact.