at the momant our frontdoor opend with the fingerprint, but this wouldn’t work 100%. Now I’m looking for a solution. My idea is a 12v relay with a potentialfree contact. Outside a bring a NFC stiker near the frontdoor and wenn only I scan the tack the door open.
The 2 question are is a 12v relay with a potentialfree contact supportet in home assistant?
And is it possible to trigger the automation from the nfc only with my smartphone?
From the 12v to the buck converter (12->5v) this powersupply to the esp. From the esp 3.3v and ground to the relay and the pin 5 use for the in from the relay.
Should be. You need to have the automation set up and the ha app running on your phone. Also being connected to ha the time you do the scan (probably via wifi) would be mandatory that your “call” reaches ha to trigger the automation to open your door.
That way of setup might be smarter safer than using a nfc/rfid reader on the door that opens when a specific uid is presented. That’s because many readers don’t even check cryptographic signatures of tags (or they don’t have one at all) or even when they do the implemented way can have it’s own weaknesses (like mifare classic)…
The way you do is that you keep all the “secretes” with you in your pocket (your phone stores the passwords etc.) and they actually never get “read out” but just trigger something if you give the input (in that case reading a nfc tag)