Upgrade of the Key Hanger V2 (https://makerworld.com/en/models/625534#profileId-549934) with the addition of a sensor to trigger automations (e.g. via Home Assistant) for those that sometime forget to lock the outside door.

This key pendant is compatible with the original hanger, but adds a place for a small 6x2 mm cylindrical magnet to trigger the popular ZigBee door/window sensor by Sonoff (use SNZB-04, not SNZB-04P).

Assembly is pretty straight-forward

1. Print both the holder and the pendant.
2. Insert the 6x2 mm cylindrical magnet into the bottom of the pendant. It should be a tight fit, a drop of glue can be applied to make sure the magnet doesn't fall out.
3. Disassemble SNZB-04 door/window sensor and pair it to your home automation system.
4. Insert the circuit of the door/window sensor into the base of the hanger as shown in the picture.
5. Mount the hanger.