Much of computer system development today is programming in the large-systems of millions of lines of code distributed across servers and the web. At the same time, microcontrollers have also become pervasive in everyday products, economical to manufacture, and represent a different level of learning about system development. Real world systems at this level require integrated development of custom hardware and software.How can academic institutions give students a view of this other extreme-programming on small microcontrollers with specialized hardware? Full scale system development including custom hardware and software is expensive, beyond the range of any but the larger engineering oriented universities, and hard to fit into a typical length course. The course described here is a solution using microcontroller programming in high level language, small hardware components, and the Arduino open source microcontroller. The results of the hands-on course show that student programmers with limited hardware knowledge are able to build custom devices, handle the complexity of basic hardware design, and learn to appreciate the differences between large and small scale programming.