The author, David Gouldin, created a "Poop Button" using Amazon IoT button, Twilio's Python Helper Library, and AWS Lambda function to help potty train his toddler. The button triggers an AWS Lambda function that uses Twilio to call the parent's phone when the child presses it, indicating they need to use the bathroom. To set up the Poop Button, one needs to purchase an Amazon IoT button, sign up for a Twilio account and an AWS account, and configure the AWS Lambda function with Twilio's Python Helper Library. The author provides step-by-step instructions on how to set up the system, including configuring environment variables, creating a new Lambda function, and setting up the AWS IoT trigger. The Poop Button is a creative solution that uses third-party services to help parents with potty training, and it has been successful in helping the author's toddler overcome nighttime emergencies.