Simple Mailbox notification - Sometimes Low-Tech is a better way to go

Shortly after I began using Home Assistant, I decided that one thing that would be helpful was to have a notification of when the mail was delivered. (The postal carriers for our neighborhood have an “eccentric schedule”.)
It was an easy thing to install an open/closed sensor on the door of the mailbox, but that would only tell me whether the door was open or closed at that moment.
I have a tendency to default to programming (years of practice), so I added a “helper” switch that would be turned on when the door was opened. There was an automation that turned the switch on whenever the open/closed sensor said the mailbox door was open. That worked, with one caveat: The switch needed to be turned off. I could do that manually (which I would do when I’d taken in the mail) or programmatically at the end of the day so that it could be triggered the next day (which I also did, just in case).
My father-in-law, a farmer, had come up with a no-tech solution for his mailbox: He mounted a hinge on the front of the mailbox unattached at the top so when the box was opened, the hinge would flip down. He mounted a reflector on the top of the hinge, both to weight it so it would flip down reliably and so he could easily see that the hinge was up (no mail yet) or down (mail has been delivered). When someone gets the mail, they simply flip the hinge back up when they close the box.
I realized that I could use a version of this. I have the hinge, but instead of a reflector, I have a small magnet mounted to the top. Inside the door of the mailbox, I mounted the open/closed sensor so that when the hinge is flipped up, the magnet closes the sensor. When it flips down, the sensor reads open. There’s no need for the helper switch and thus no need to reset it. (The resetting is done when you get the mail and flip the hinge back up.) No automations required.
Sometimes, low-tech is the better way to go.