Long before the Internet, sensor- and actuator-based electronic control systems existed in high-tech automation systems. In those systems, sensors were interfaced to the microcontroller via hard-wired connections. Due to extensibility limitations, the coverage area of these systems was geographically restricted. Examples of these high-tech systems included factory automation, satellite systems, weapon systems, and so on. In most cases, the sensors used in these systems were huge and the microcontrollers were also limited by their low computational capabilities.

With recent advancements in technology, especially in the semiconductor industry, the physical size of sensors and microcontrollers has significantly reduced. It has also been made possible to manufacture low-cost and highly efficient electronic components, hence today it is relatively inexpensive to develop small and efficient sensor-based hardware products. Arduino and Raspberry Pi are great examples...