Physical Computing is about integrating the real world with sensing, communication, and computation. It is about rapidly prototyping devices that can react and interact directly with their environment, rather than being accessed through a keyboard and monitor. The class introduces students to the idea of using small, programmable microcomputers to build self-contained, physical systems that help automate everyday tasks. The course exposes students to basic electronics, microcontroller programming, wireless networking (WiFi and Bluetooth), mobile interfaces (smartphones), and embedded sensing. The class centers on Arduino and ESP development boards that allow one to rapidly build reactive and/or interactive everyday items, without the need for attaching a Mac or PC to them.