The objective of this chapter is to demonstrate in action the concepts discussed in this book. Simply put, our goal is to provide the theory, design, and construction of a passively heated greenhouse. We equip the greenhouse with instrumentation to monitor and control key parameters. Using IoT concepts key parameters will be monitored and controlled remotely. Via a greenhouse controller example we demonstrate how to interface different sensors and actuators to an Arduino Opta PLC. These examples may be used and adapted for many other non–greenhouse systems.