Machanical lock sensor

[HomerNau]

Hi,

Can anyone assist in a sensor that can detect an object in a very small space. I want to detect if a normal house door is lock/unlocked.

The lock is the normal mechanical lock, turn the key to lock/unlock.

The plan is to design a easy install sensor that will detect the deadbolts position

A future add-on will to have the sensor connect to a smart-phone via blue-tooth

[A Former User]

Is it possible to put a small push button switch in the dead bolt area of the door frame? It would be pressed when the dead bolt was engaged.

[hek]

Something like this perhaps:
http://www.ebay.com/itm/10PCS-Micro-Switch-Spdt-Hinge-Roller-Lever-15A-V-156-1C25-/220997799549?hash=item33747ece7d:g:sEcAAMXQwKdRd~U0

[A Former User]

I was thinking more of something like this. The switch could be installed inside the dead bolt hole in the door frame. The dead bolt when engaged would depress the switch. It will require some mechanical skills to get it installed in the door frame.

http://www.ebay.com/itm/New-Black-10Pcs-Mini-Momentary-On-Off-Lockless-Micro-Push-Button-SPST-Switch-/191681039000?hash=item2ca1148a98:g:6TcAAOSwEetV~gt1

[hek]

The microswitch is much better for that purpose. It requires much less force and is more durable.

[A Former User]

How would you propose to mount it so the action of the dead bolt would activate it?

[hek]

Like this perhaps:
http://www.automatedhome.co.uk/reviews/led-door-lock-status-indicator-hack.html

[HomerNau]

Thanks for the quick reply.

My idea is to design it in such that it can be installed by anyone; after market (even the 100 year old granny :-))
No wires and works from a Lithium battery; with the capability to upgrade to Bluetooth, connection to a smart phone.

What you guys suggest is mechanical and can fail due to dust, rain and bugs.

What I have in mind is a type of proximity sensor, small enough to go between the door and frame (close to the deadlock) to monitor its position, thus it will only work with door locks that have a latch and deadlock. The other types I will think about on another occasion.

Three types of sensor came to mind, hall sensor, capacitance and Optical. My problem is SIZE. Some gaps are 1mm or less (but of course we need to be realistic and draw the line of how small do we go).

If anyone knows about a sensor that will detect a deadlock and is small enough to go between the door and frame.... please help.

[HomerNau]

Any Idea on optic fiber?

[hek]

The "run from Lithium battery" requirement, pretty much rules out anything but a physical switch.

[mfalkvidd]

The sensor used in http://forum.mysensors.org/topic/3139/fun-with-magnetometer-digital-compass-sensors/6 might be a bit too large but maybe smaller versions exist?

[tbowmo]

@hek said:

Like this perhaps:
http://www.automatedhome.co.uk/reviews/led-door-lock-status-indicator-hack.html

Hmm.. that made my "hacking the house brain" tick extra... :) Wonder if the wife would allow me to hack the doors..

[bjacobse]

I found those "authorized" and they are damn expensive
http://hansenlellinge.dk/produkter/11-el-laase-og-tilbehoer/10423-effeff-slutblikskontakt-877/
http://hansenlellinge.dk/produkter/11-el-laase-og-tilbehoer/10408-assa-slutblikskontakt-82/