Domoticz

I want to build a simple alarm system. So I would provide the doors with contacts from Xiaomi and send a push message when opening, or play a sound via the Xiaomi gateway. I'm still thinking about how to activate the system. I imagine a button that can be used to activate and deactivate the system. Does anyone know of a thin button that works with Domoticz? But I don't want to work under plaster.
Another idea would be to use a small button for the keychain, e.g. a remote control from Sonoff. Or does someone have a completely different idea?
Thanks for your advice.

if you have zigbee, the aqara buttons work great

Thanks, ordered.