Z-Wave Deadbolt Tilt Switch

Shortly after moving into a new apartment building my sister mentioned to me in passing that she, like many people, would often second-guess whether or not she had remembered to lock her door on her way out. Since she was renting, replacing the deadbolt with some form of smart lock wasn't an option; the solution had to be easily removed when she decided to move.

While battery-powered WiFi/Z-Wave/ZigBee tilt sensors do exist, most of them are aimed at overhead garage door installations, and are quite chunky - definitely not suitable for mounting on a deadbolt. After looking at the various options on the market, I settled on the Dome DMWD1 Z-Wave door/window sensor and set about modifying it to replace the magnetic reed switch with a tilt sensor.

With the top cover removed, the PCBA could easily be popped out by pressing on four plastic tabs located at the corner of the board. The magnetic reed switch (long black component in the middle) was desoldered and two wires soldered in place, which would be run off to the ball-bearing style tilt switch.