A reliable mailbox sensor

I love getting mail. It's like a surprise gift that arrives six days a week, and I look forward to seeing what I've gotten, even if some days it is only bulk mail. But I don't like walking out to the mailbox and finding it empty. That's always a disappointment. So I decided to add a home automation sensor that would let me know when the box has been opened, so I can rush out and see what treasures the carrier has delivered. The mailbox is too far away from the house for a traditional sensor. Fortunately, I'm already running a LoRa network, which has a very long range (up to 1/4 mile), so I investigated the devices available from YoLink. I briefly considered their vibration sensor, but rejected using it because my mailbox shares a mounting post with my neighbor's box. And both boxes jiggle whenever either is opened. I only want to be notified when my box is opened, not theirs. I ended up using the YoLink motion sensor instead. It's a standard passive-infrared device, but putting it…