One of the failings of most alarm systems is that they only monitor that you have doors closed and do not tell you if you have locked the doors. I decided to re-purpose common garage door monitors to function as a 'locked door' reporter. I recently came across 'Deadbolt Beacons' that attach to your deadbolt turn knob and I now use them on doors that are easy to see but they aren't useful for remote doors that are not easily seen. I put the monitors on my entertainment center so I can easily see if the doors are locked from my seat.
Here you see the transmitter that sends the open/closed signal to the receiver. It is triggered by a magnetic switch in the door jamb that is operated by a small magnet epoxied to the end of the deadbolt.
Here you see the magnet epoxied to the end of the deadbolt. The small magnet came with the magnetic switch (although it was in a plastic enclosure that I cut it out of).
The magnetic switch inserts into a hole drilled in the door jamb. A second hole is drilled at an angle from the inside wall by the door molding to intersect the switch hole. The plastic wire mold hides the wire and hole.
This is the magnetic switch.
This is the slider switch assembly. I cut a small block of wood to fit into the slider jamb. A hole bored in the wood made space for the switch. I glued a piece of aluminum flashing to the back side to provide a means of mounting the switch with small bolts. I made a plastic bushing that guides a small nail that, after several adjustments, worked the switch when the slider door was locked. You can see the head of the nail just below the switch arm.
The hook on the slider moves up when the slider is locked and also pushed the nail up, triggering the switch.
A cover was made by spray painting some cardstock on both sides with white spray paint to make it water resistant. I attached that with double-faced tape. The wood block was attached to the door jamb with automotive grade double faced tape.
This is the modified transmitter. It normally attaches to a garage door with double faced tape and as the garage door opens, a 'gravity sensor' triggers the signal as the transmitter moves into a horizontal position. I cut one of the wires off the gravity sensor (left wire) and attached my circuit (magnetic switch on the deadbolt, mechanical switch on the slider) to that and the still intact wire. Now the transmitter sends the signal to the receivers and I can sit watching TV and see if my doors are locked!
The garage door monitors and magnetic switches came from eBay, the mechanical switch from Radio Shack. Most of the other common components I had lying around, if not, Home Depot!