Development of nodes for the Internet of Things (IoT) requires a robust set of tools. Along with the usual tools used in embedded systems such as compilers and debugging tools, there is a need for a modular set of software tools for connectivity, software interoperability, and flexibility. Such a system is the mbed platform for the ARM Cortex series of embedded processors. With the recent introduction of version 5, the ARM mbed group has a mature yet still growing platform of open-source tools that are being developed and refined by a network of partners around the globe. In this introductory course, we will look at the history and structure of mbed, the tool chains that are supported, and the direction that mbed is taking in the development of the IoT. In later CEC courses, we will look in more detail at some of the more complex aspects of mbed including communications, porting, and security.