You want to receive a call notification when someone is detected by your Google Nest security camera, but the built-in feature does not allow this. To solve this problem, you can use Twilio and CloudMailin to create a system that alerts you via phone call whenever a person is detected by the camera. The process involves configuring the Nest notifications, creating a Twilio project with a custom TwiML response, setting up a CloudMailin account, forwarding GMail notifications to the CloudMailin mailbox, and finally testing the entire integration.