This tutorial uses the Twilio Narrowband IoT Developer Kit to build a data tracker for a sourdough starter, which is a little yeast-driven pet that eats flour and water and makes sourdough. The kit has some great sensors that can be used to get started, including temperature, humidity, and rise sensors. However, it only works in the US, and there are plans for another bread monitor that connects with Super SIM, which is available everywhere. The project requires a Twilio account, an Arduino IDE, an MQTT broker of choice, and some custom firmware to add functionality. The final product is a small enclosure that can be printed or purchased, which tracks the starter's temperature, humidity, and rise, providing insights into its health.