Publisher Summary This chapter presents useful applications for real-time control circuits designed to perform some specific low-level task and interface with a master controller for instructions and overmonitoring. The focus is to provide introductory-level information on how to interface with some common robotics-type sensors and actuators, and in particular to show how these can be tied into the system. An overall system configuration is discussed where all devices are connected directly to the Linux SBC. This configuration is easy to develop and test and is an excellent basis for many types of projects. The concepts of E2BUS PC-host interface, host-to-module communications protocol, stepper motor controller, speed-controlled DC motor, and RS-422–compatible indicator panel are also discussed.