The insight we gain from an IoT system is derived from the data obtained by its sensors. Driven by innovations in materials and nanotechnology, sensor technology has been developing at unprecedented speeds and has resulted in lower-cost sensors that have better accuracy, are smaller in size, and able to detect or measure the presence of objects that were previously not possible.
A sensor is a type of physical device that converts one form of energy into another. Industries and organizations have been using various kinds of sensors for a long time, but the invention of IoT has taken the sensor evolution to a completely different level. IoT systems collect different types of data using a variety of sensors and share it with a network of connected devices. The abundance of data makes it possible for devices to function autonomously and enables the IoT ecosystem to become “smarter” every day. Through combining a set of sensors with a communication network, IoT devices can share information with each other and improve their overall effectiveness and functionality.
Common IoT Sensors
Finoit has compiled the top 15 sensor types being used in IoT. See Figure 1.
Temperature Sensors – Detects a physical change in heat energy for a particular source and converts this change into data for a device or user. Temperature sensors have been deployed in countless devices and applications over the years.
Proximity Sensors – Detects and converts the presence or the properties of a nearby object into a signal that can be interpreted by a user or an electronic instrument that does not need to come into contact with said object. These sensors are primarily used in the retail industry because they can detect motion and provide retailers with insights about their customers who show potential product interest. Motor vehicles are another popular use case for these sensors. When you are notified about an obstacle while driving in reverse, a proximity sensor has done its work.
Pressure Sensors – Measures the force required to keep a material from expanding within a given space and convert this into an electrical signal. The strength of the electrical signal depends upon the amount of pressure detected. Pressure sensors are used in a class of IoT applications that are very useful in manufacturing because they monitor systems and devices that are pressure propelled.
Water Quality Sensors – Detects, monitors, and maintains various ion levels in water distribution systems. Since clean water is essential for human survival, these sensors play a vital role in ensuring water quality for a variety of industries.
Chemical Sensors – Detects changes in targeted liquids and gases and transforms this into a measurable signal. Use cases for these sensors include industrial environmental monitoring and process control, detection of intentional or accidental release of chemicals as well as explosives and radioactive materials, and processes of the pharmaceutical industries and laboratories.
Biosensors – Measures biological or chemical reactions by generating signals proportional to the concentration of an analyte in the reaction. Biosensors are ubiquitous in biomedical diagnosis, as well as a wide range of other areas such as point-of-care monitoring of treatment and disease progression, environmental monitoring, food control, drug discovery, forensics, and biomedical research.
Gas Sensors – Similar to chemical sensors, but they are specifically used to monitor changes in air quality or to detect the presence of gases. Gas sensors are used in numerous industries such as manufacturing, agriculture, mining, petrochemical, and pharmaceutical.
Smoke Sensors – Detects specific airborne particulates, gases, and the smoke level in a given space. When they are connected to an IoT system, they can immediately alert occupants and emergency personnel when smoke is sensed and help minimize damage and injuries.
IR (Infrared) Sensors – Identifies certain characteristics about their surroundings by emitting or detecting infrared radiation. IR is invisible to the human eye, as its wavelength is longer than that of visible light. Anything that emits heat gives off infrared radiation. IR sensors can measure the heat of objects as well as detecting motion.
Level Sensors – Determines the amount of liquids, fluids, or other fluidized solids that can flow in systems or containers. They are primarily known for measuring fuel levels, but they are also used in industries that work with liquid materials.
Image Sensors – Converts optical images into electronic signals to digitally display or store files. They are primarily used in digital cameras, medical imaging and night vision equipment, thermal imaging devices, radar, sonar, and biometric and iris devices.
Motion Detection Sensors – In a given area, motion detection sensors detect the physical movement, or motion, of an object or person and transform it into an electric signal. Motion detection plays an important role in the security industry.
Accelerometer Sensors – Detects physical or measurable acceleration of objects responding to inertial forces and converts mechanical motion into electrical output. These sensors are present in millions of devices, including smart phones and smart pedometers, used to detect vibrations, tilting, and other forms of acceleration. They can also be great for monitoring driving fleets.
Gyroscope Sensors – Measures the angular and rotational velocity of objects in 3-axis directions. Common use cases include car navigation systems, game controllers, cellular and camera devices, consumer electronics, robotics control, Unmanned Aerial Vehicle (UAV) or drone control, and Advanced Driver-Assistance Systems (ADAS) or vehicle control.
Humidity Sensors – Detects and measures the amount of moisture in the air and air temperature. Humidity sensors are commonly found in heating, ventilating, and air conditioning systems. They can also be found in vehicles, museums, greenhouses, meteorology stations, paint and coatings industries, and hospitals and pharmaceutical companies.
Automobile IoT Sensors
In addition to common IoT sensors, there are sensors specially designed, configured, and used in the automobile industry that are known as automotive sensors. These sensors usually operate in harsh conditions which involve extreme temperatures, vibrations, and exposure to environmental contaminants. In fact, cars already field more than 100 sensors, according to Dragos Maciuca, the executive director of Ford Motor Co.’s Research and Innovation Center in California. That number of sensors grows to more than 600 for electric vehicles. All these sensors transform automobiles into mobile Internet of Things (IoT) devices.
One typical use case of car sensors is the 360-degree camera system, a key component of a car’s surround view sensors, provides a driver with a real-time view of the area surrounding a car. The 360-degree camera technology combines the perspectives of several video cameras around the vehicle into one image – typically a top-down view. As a driver maneuvers into a parking space, the 360-degree camera system shows nearby obstacles, which helps the driver avoid impact.
So far, we have covered data characteristics and sensors of the IoT ecosystem. Please stay tuned for the next article on data communication in this series about IoT.
Author Biography
Dr. Qiang Lin is a Lead Systems Engineer at The MITRE Corporation and is a well-known expert on data architecture, data modeling, data engineering and data governance; he has assisted DoD, U.S. Army, U.S. Air Force, DHS, VA, IRS on many data management and data engineering projects for over 30 years. He has been an adjunct faculty at George Mason University since 2001. He is the co-author Internet of Things Ecosystem: 3rd Edition, published in March 2022.
‘The author’s affiliation with The MITRE Corporation is provided for identification purposes only, and is not intended to convey or imply MITRE’s concurrence with, or support for, the positions, opinions, or viewpoints expressed by the author.’
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