While some high school courses like the AP Computer Science Principles cover topics such as the internet, they do not typically include hands-on activities on the Internet of Things (IoT) and related concepts such as distributed computing. Notable reasons include the complexity of programming distributed systems and the cost of supplying an entire classroom with the necessary hardware. However, most students already have access to a smartphone or other mobile device, which contains all the necessary hardware to introduce these topics through highly engaging and interactive projects. We introduce an open-source mobile app called PhoneIoT that allows students to remotely access their devices and query live sensor data or manipulate the app’s customizable interactive display. Importantly, unlike other tools such as App Inventor, PhoneIoT is not an app-creation tool; instead, we take a distributed approach, with students’ code running on their computers and remotely accessing the phone. This makes it possible to have multiple student programs connect to a single device, or one program connect to multiple devices, creating a truly distributed application. To target broad audiences, PhoneIoT supports simple programming interfaces in both block-based form through NetsBlox (a networking-oriented fork of Snap!) and text form through a Python library called PyBlox. This demonstration will include the basic information needed to install and use PhoneIoT, an interactive walkthrough of a compelling NetsBlox project that students could complete on their first day using PhoneIoT, and finally a demonstration of a few interesting projects implemented in Python.