That’s a great idea—an open‑door alert will save you a lot of worry. I’d recommend a magnetic reed switch paired with a smart plug or a Zigbee sensor so it can ping your phone when the latch releases. If you already have a hub, you can set up a routine that triggers a notification or even lights a bulb red when the door is left open. Just wire the switch to a low‑power microcontroller, keep the battery low‑drain, and you’ll have a tidy, reliable system in no time. Let me know if you need help choosing the exact model or setting up the alerts.