Make your apartment buzzer smart with Twilio Functions

I wanted to make my apartment buzzer acessible without a physical key, so I created these Twilio Functions to make my buzzer smarter. Features include:

• Voice password (make your friends shout stupid things in public to get into your building!)
• PIN password, a classic
• No obvious weirdness or extra waiting for first-time guests or delivery people
• Notify multiple people until someone picks up the phone - as long as one of the roommates pick up, you won't miss your package

I kind of went overboard I think, given my original goal. But this was actually really easy to develop and set up. And also really cheap.

How to set this up

1. You could git clone https://github.com/jlian/smart-door-buzzer-twilio-functions.git, but it's not critical.
2. Get a Twilio account and valid Twilio number.
3. Go to https://www.twilio.com/console/runtime/functions/manage and hit +.
4. Add each of the 4 .js files into its own function with names that you'd remember.
5. Go to https://www.twilio.com/console/runtime/functions/configure and configure the environment variables:

• TWILIO_PHONE with the Twilio number you bought
• PASSPHRASE for voice password
• PASSCODE for PIN
• JOHN_PHONE and others for your cellphone number

5. Go to https://www.twilio.com/console/phone-numbers/incoming and select the phone number you bought earlier.
6. Scroll to where it says A call comes in, select Function, and then the function that corresponds to buzzer-activated.js.
7. Contact your HOA to make the Twilio number your buzzer number - this might be the hardest step.

How this works

Twilio Functions is pretty sweet. It's completely serverless so you don't need a VM or computer to keep running an app. It's perfect for something small scale like your apartment buzzer. The flow of this program goes like this:

1. A call comes to the Twilio phone number, buzzer-activated.js runs.
2. The Gather verb is used to get either a voice password or a 4-digit PIN.
   1. If correct, door-open.js dials a 9 to the buzzer (my building's buzzer code, yours may be different), which opens the door.
   2. If incorrect, call-residents.js calls all the residents until someone picks up and manually dial 9 to open the door.
3. When everything is finished, text-me.js texts a specified number with info on what happened.

How much this costs

According to Twilio docs, collecting speech is charged at $.02 per 15 seconds. A Twilio number costs $1/month. Looking at my own billing dashboard, it never exceeds $2/month - pretty reasonable.

More details

See State of my home automation in 2018.