Raspberry Pi based Doorbell
Weekend project for a DIY-smart doorbell
What it does
Doorbell that notifies on your Google Home as well as your phone via SMS.
How it works
The expected external circuit should be connected to the GPIO channel for voltage and the GPIO ground to setup a closed circuit. When the circuit's switch is pressed, the circuit will open and the GPIO notification callback will get a message that the circuit is no longer closed. This will trigger the notification code to send SMS message to all your configured recipients via Twilio as well as Chromecast a notification message to your Google Home.
Sources
gpiotest - Used for some simple examples of how to interact with the GPIO bus on Raspberry Pi
GooglePyNotify - Adapted for on-demand Google Home notifications