You could also consider to decouple the sensor from the Christmas ornament an broadcast the values over BLE or WiFi. That way you could place the sensor in the

You could also consider to decouple the sensor from the Christmas ornament an broadcast the values over BLE or WiFi. That way you could place the sensor in the window without rethinking the rest. I think the greatest disadvantage would be that you have to relocate the sensor with the ornament.