[drewzero1]

Wow, and I thought my doorbell was complicated! I used an ESP-01 with a button to send an HTTP request to my home server, which would send me an XMPP message (to my phone and watch) and also send an HTTP request to another ESP01 which was connected through a relay to an old elevator bell, which would flash and ding twice. It worked reliably enough but some times it would take up to 30 seconds after pushing the button before the bell would ring.

Now that I'm in a house I installed a boring old wired doorbell which doesn't send me any messages, but does ring instantly every time it's pushed.

Edit: How does the reed switch work inside the doorbell? Very intrigued by this setup.

[rcarmo]

Electromagnetism. It’s inside the bell coil.

[drewzero1]

Oh, that makes so much more sense. For some reason I was thinking the reed switch was inside the button! Those coils are pretty strong.