Types of sensors used in the Internet of Things
There are many types of sensors, some of which are described here.
Temperature sensors
To measure the external temperature we have temperature sensors. This is estimated by environmental factors such as physical, chemical, mechanical, electronic, and biological systems showing variations with a rise or fall in temperature. There are basically four kinds of temperature sensors:
Thermocouple sensors: This is a type of sensor that contains two distinct and unlike conductors in contact. The power is created with the help of the thermoelectric effect. The sensor is comprised by assembling two disparate metals on one end.
Resistance temperature detector (RTD) sensors: These are radar equipment that senses temperatures, and even minute changes can be recorded and resisted. They were used for a long time for recording temperatures in laboratories and other industrial processes. They have proved themselves for accuracy and efficiency.
Thermostats: These are similar to the RTDs, they have no resistance to changes in temperatures. They are made from semiconductor materials.
Semiconductor sensors: These are of various types, like the voltage output, the output for current, digitally supported output, resistance output, and silicon-diode temperature sensors. The new types of sensors are accurate and highly efficient.
Pressure sensors
Such sensors aid in measuring the pressures of solids, liquids, or gases and they also include water levels, and the flow, speed, and height of fluids. Examples of such sensors are those used for compressors, pumps, hydraulic systems, and refrigerators, etc.
Imaging sensors
These are complicated sensors that are deployed in digital cameras, computer vision, medical imaging such as X-ray scans, and night vision tools. They give a precise record of information by capturing the image that supports great lens capacities and then convert the variable attenuation of waves into signals.
Noise sensors
These help to edit the high noise which may damage human ears (e.g., permanent or temporary deafness, cardiovascular diseases, stress, hypertension, etc.) and even animals (for instance, deafness). The noise may be caused by appliances at home, machines, construction sites, airplanes, trains, and loudspeakers, etc. and are basic causes of noise pollution. Many firms have started to install sensors to keep a track of noise pollution. Ambient sensors for noise monitoring are also used in health care for patient comfort in hospitals. Noise level changes are explicitly observed and the signals of change are transferred over the device for appropriate action which may be automatic or manual.
Air pollution sensors
The rising pollution concerns are giving way to the installation of such sensors that monitor and even regulate air quality in urban areas. Air pollution sensors detect and monitor the presence of air pollution in the surrounding environment. They are basically concerned with five components: ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrous oxide.
Proximity and displacement sensors
These sensors aid in detecting the existence or absence of an object by utilizing electromagnetic fields, waves of light, or sound. There are various types that suit specific applications and surroundings.
Inductive sensors: To monitor very close-range detection of ferrous elements;
Capacitive sensors: These are meant for nonferrous materials detection;
Photoelectric sensors: These are to detect long-range targets;
Ultrasonic sensors: These serve the purpose of detecting the long-range distance of objects with very rough surfaces.
Infrared sensors
These sensors help to track the movement of an object. Heat helps to detect infrared rays and this eases the process of detection.
Moisture and humidity sensors
These are also known as hygrometer sensors. They enable us to report and calculate the degree of relative humidity of the atmosphere. They tend to rely on electrical capacitance to discover the degree of capacitive measurements.
Speed sensors
These sensors are generally used to measure the speed of means of transport, such as those in air, water, or land. Wheel speed sensors, speedometers, Doppler radar, and laser surface velocity meter are examples of these sensors. There are other sensors available in the market including sensors that measure acceleration, biosensors, sensors for gas and chemical reactions, mass sensors, tilt sensors, force sensors, etc.