The phone will ring if you have an alert in your AWS Cloudwatch. If you pick up the handset, it tells you whats wrong. For this project I hacked an old rotary phone, so it will tell me if a HTTP server in my AWS account is down. To do this a Lambda function will check via Cloudwatch Events an EC2 instance by checking a HTML page. The Lambda function is tracked by a Cloudwatch Alert. If the check fails, an alert is triggered and a SNS message is sent to a topic. A second Lambda function is connected to this SNS topic and will forward this message to a MQTT topic. The Pi Zero in the red phone is subscribed to this topic. If a MQTT message is reaching the red phone, it will ring, the Pi than calls the AWS Polly API to transform the text message into an Audio File an plays it on the handset.”