What do we mean by environmental monitoring?

Sensors play a critical role in environmental monitoring. They help to measure a quantity and provide a signal, typically electrical, as an output. A sensor can be considered an intersecting coordinate of a two-dimensional graph with two varying parameters, such as temperature and resistance or distance and time. Based on the output, sensors can be further classified as analog (continuous), digital (discrete), or binary (zero or one). With the advancements in silicon nanotechnology and digital electronics, sensors have rapidly evolved, reducing in size, improving in accuracy, methods of sensing and speed, and so on. Integrating the compute, storage, and transmission modules within the sensor unit has blurred the boundaries of the actual capability of the components.

Figure 3.2 generalizes the types of sensors pertinent to the industry with the property as a basis of classification. Each fulfills a specific role in quantifying a manufacturing...