## 2 Background
### Different Types of Sensors  
A sensor is a device that identifies and captures specific readings when deployed in an environment. A sensor transfers physical phenomena into digital signals that are displayed, read, or processed. Different types of sensors are used in WSN applications. In WSN, several sensor types are considered for environmental monitoring, air and water quality monitoring, smart lighting, traffic management, and healthcare applications. * Temperature sensors: These sensors monitor temperature variations, where the variations could trigger certain actions. * Humidity sensors: These sensors detect water content in the air, and their application could activate after reaching a predetermined threshold. * Wind speed sensors: These are also known as anemometers, employed to compute wind speed in the environment. * Rain sensors: These find the presence and intensity of rainfall. * Proximity sensors: These are motion sensors that detect the presence of objects and calculate their distance. * Pressure sensors: These sensors identify pressure, and their application may alert system administrators to pressure range divergences. * Air and water-quality sensors: These sensors observe the integrity of air that is activated by the presence of contaminants. * Electrical sensors: These sensors determine the active electrical current in voltage or average. This sensor is associated with an alert or preservation ticketing program. * Status sensors: These sensors function as simple on-off switches and vary in status based on different stimuli. * Motion sensors: These sensors are designed to detect motion, and their application may activate the appropriate tangential action. * Optical sensors: These optical sensors are devices that use light, radiation, electric, and magnetic fields to monitor various variables. They are often used in industries such as healthcare. * Gas sensors: These determine precise gaseous pollutants, namely, nitrogen dioxide (NO\({}_{2}\)), carbon monoxide (CO), sulfur dioxide (SO\({}_{2}\)), ozone (O\({}_{3}\)), and volatile organic compounds (VOCs). * pH sensors: These are vital for assessing water quality, detecting pollution, and safeguarding aquatic ecosystems. * Conductivity sensors: These compute the presence of certain gases in the air for finding changes in the heat transfer rate depending on their thermal conductivity. * Dissolved oxygen sensors: These estimate the concentration of dissolved oxygen in water. * UV sensors: These sensors measure the level of ultraviolet radiation in the atmosphere. * Water-quality sensors: These sensors are utilized in ecological organizations to measure the levels of chemicals and ions present in water. * Chemical sensors: These sensors can detect the presence of chemicals in water and are often used to monitor air and water quality in urban areas and industrial processes. * Smoke sensors: These identify the presence of smoke in the air. * Level sensors: These calculate the levels of fluids and other substances in both open and closed systems. While they are commonly used to determine fuel levels, they can also be used to measure the levels of reservoirs. * Image sensors: These sensors are used in digital cameras and medical imaging. * Vehicle detection sensors: These sensors find the presence of vehicles on the road to estimate changes in electromagnetic fields, reflected light, or sound waves based on the sensor type. * Ultrasonic sensors: These determine the presence of vehicles for real-time traffic monitoring. * Body temperature sensors: These observe the patient's temperature for detecting and managing complications. * Heart rate sensors: These examine heart rate, assess cardiovascular health, and recognize irregular heartbeats. * Blood pressure sensors: These measure patients' blood pressure. * Respiration sensors: These compute breathing activity to monitor respiration in healthcare. * Accelerometer sensors: These measure the rate of change in velocity of an object in terms of acceleration.