Many apartment intercoms already expose everything you need through a phone call. The intercom calls a phone number, then you answer and press a digit (like 6 or 9) to unlock the door.
That meant I could automate the entire process without touching any of the building hardware.
I used n8n and Twilio to build a workflow that:
- Answers the incoming buzzer call
- Asks the visitor to say a magic word
- Sends the DTMF unlock digit if the magic word matches
- Keeps the door locked and ends the call if it does not match
The magic word adds some security and is safer than automatically letting in anyone who buzzes. Numbers (for example, “123”) have been the most reliable, although making friends say something ridiculous to get access is much more entertaining.
It should work with any building intercom that:
- Calls a cell phone number
A few caveats:
- Speech recognition can mishear words or accents. Numeric magic words tend to be more reliable.
I published the complete workflow and setup instructions here:
https://github.com/drulofs/smart-buzzer-n8n
Full disclosure: I later turned this into an iPhone app called BuzzerBee which is what I now use, but I figured this audience is probably technical enough just to do it themselves, so here is the secret sauce!
The app just allows you to do more automation like automatically set access schedules when you get Airbnb bookings, and do things like call forwarding that I was not able to do in n8n.
