I bought an RF keypad based front door lock from the states on an Amazon sale cheap, about $120 NZ landed. I thought the Mi brand would be fairly cheap quality based on the price, but it isn't actually too bad at all. Solidly built. The only possible issue is the 4 x AA batteries in the back to trigger the lock/unlock mechanism didn't last long - I say possible, as I can't remember if they were new batteries I put in or ones my kids use in their Wii remotes! I guess I'll find out soon now I have brand new batteries in, anyways I digress...
I wanted to have the door lock automated / controlled from OpenHAB, so ripped open the key fob and wired it up. I got it working with an ESP8266-01 initially, but had issues because you have to keep GPIO pins 0 high on startup - doing this triggered the transistor to switch, unlocking the front door on power up. Not good! Experimented with NPN and PNP combo's but eventually gave up - I went to a Wemos with a couple 2N7000 MOSFETs and 2 x 10K pull down resistors. The keyfob generally uses 6V's (2 x 3V button cell batteries) but I'm just powering it using 5V from the breadboard - seems to be ok, no different than when a battery gets old I guess.
The Wemos is pretty cool, but its a bit bigger than the native ESP8266. I have an ESP8266 v12 around somewhere so might give that a go instead as its smaller. Anyhow the point of the post is an option to provide a basic / cheap alternative automated front door lock. I have it triggered to lock automatically at night, and can remotely unlock/lock the front door from my iPhone too. Always good for those "did you lock the front door honey?",... "no, i told you too",... "but I was already in the car you were last out",... "well I'm not walking back up the front steps to check the door, if you weren't so %#$ lazy i wouldn't have had to run around after the kids getting them ready to go out while you sit there all afternoon drinking beer and watching the league!",... "argh, i'll lock the door with my phone. and oh yeah, you're right - i've been drinking,... here you drive" moments.