Sensors are everywhere. They’re in our homes and workplaces, our shopping centers and hospitals. They’re embedded in smart phones and an integral part of the Internet of Things (IoT). Sensors have been
around for a long time. The first thermostat was introduced in the late 1880s and infrared sensors have been around since the late 1940s. The IoT and its counterpart, the Industrial Internet of Things (IoT), are bringing sensor usage to a new level.

Broadly speaking, sensors are devices that detect and respond to changes in an environment. Inputs can come from a variety of sources such as light, temperature, motion and pressure. Sensors output valuable information and if they are connected to a network, they can share data with other connected devices and management systems.

Sensors are crucial to the operation of many of today’s businesses. They can warn you of potential problems before they become big problems, allowing businesses to perform predictive maintenance and
avoid costly downtime. The data from sensors can also be analyzed for trends allowing business owners to gain insight into crucial trends and make informed evidence-based decisions.

Sensors come in many shapes and sizes. Some are purpose-built containing many built-in individual sensors, allowing you to monitor and measure many sources of data. In brownfield environment, it’s key for sensors to include digital and analog inputs so that they can read data from legacy sensors.

There are many types of IoT sensors and an even greater number of applications and use cases. Here are 10 of the more popular types of IoT sensors and some of their use cases. Followed are some sub categories of Temp Sensors:


Temperature sensors:

By definition, “A device, used to measure amount of heat energy that allows to detect a physical change in temperature from a particular source and converts the data for a device or user, is known as a Temperature Sensor.”

These sensors have been deployed for a long time in a variety of devices. However, with the emergence of IoT, they have found more room to be present in an even greater number of devices.

Only a couple of years ago, their uses mostly included A/C control, refrigerators and similar devices used for environmental control. However, with the advent of the IoT world, they have found their role in manufacturing processes, agriculture and health industry.

In the manufacturing process, many machines require specific environment temperature, as well as device temperature. With this kind of measurement, the manufacturing process can always remain optimal.

On the other hand, in agriculture, the temperature of soil is crucial for crop growth. This helps with the production of plants, maximizing the output.

Followed are some sub-categories of Temp Sensors:

Thermocouples: These are voltage devices that indicate temperature measuring with a change in voltage. As temperature goes up, the output voltage of the thermocouple rises.

Resistor temperature detectors (RTD): The resistance of the device is directly proportional to the temperature, increase in a positive direction when the temperature rises resistance going up

Thermistors: It is a temperature sensitive resistor that changes its physical resistance with the change in

IC (Semiconductor): They are linear devices where the conductivity of the semiconductor increases linearly and it takes advantage of the variable resistance properties of semiconductor materials. It can provide a direct temperature reading in digital form, especially at low temperatures.

Infrared sensors: It detects temperature by intercepting a portion of emitted infrared energy of the object or substance, and sensing its intensity, can be used to measure temperature of solids and liquids only, not possible to use it on gases because of their transparent nature.

Proximity sensor

A device that detects the presence or absence of a nearby object, or properties of that object, and converts it into signal which can be easily read by user or a simple electronic instrument without getting
in contact with them.

Proximity sensors are largely used in the retail industry, as they can detect motion and the correlation between the customer and product they might be interested in. A user is immediately notified of
discounts and special offers of nearby products.

Another big and quite an old use-case is vehicles. You are reversing your car and are alarmed about an obstacle while taking reverse, that’s the work of proximity sensor.

They are also used for parking availability in places such as malls, stadiums or airports.

Following are some of the Proximity Sensors sub-categorized:

Inductive Sensors: Inductive proximity sensors are used for non-contact detection to find out the presence of metallic objects using electromagnetic field or a beam of electromagnetic radiation .It can operate at higher speeds than mechanical switches and also seems more reliable because of its robustness.

  • Capacitive Sensors: Capacitive proximity sensors can detect both metallic as well as non-metallic targets. Nearly all other materials are dielectric different from air. It can be used to sense very small objects through a large portion of target. So, generally used in difficult and complicated applications.
  • Photoelectric Sensors: Photoelectric sensor is made up of light-sensitive parts and uses a beam of light to detect the presence or absence of an object. It is an ideal alternative of inductive sensors. And used for long distance sensing or to sense non-metal object.
  • Ultrasonic Sensors: Ultrasonic sensors are also used to detect the presence or to measure the distance of targets similar to radar or sonar. This makes a reliable solution for harsh and
    demanding conditions.

Pressure sensor

A pressure sensor is a device that senses pressure and converts it into an electric signal. Here, the amount depends upon the level of pressure applied. There are plenty of devices that rely on liquid or other forms of pressure.

These sensors make it possible to create IoT systems that monitor systems and devices that are pressure propelled. With any deviation from standard pressure range, the device notifies the system administrator about any problems that should be fixed. Deployment of these sensors is not only very useful in manufacturing, but also in the maintenance of whole water systems and heating systems, as it is easy to detect any fluctuation or drops in pressure.

Chemical sensor

Chemical sensors are applied in a number of different industries. Their goal is to indicate changes in liquid or to find out air chemical changes. They play an important role in bigger cities, where it is necessary to track changes and protect the population.

Main use cases of chemical sensors can be found in Industrial environmental monitoring and process control, intentionally or accidentally released harmful chemical detection, explosive and radioactive detection, recycling processes on Space Station, pharma industries and laboratory etc.

Following are most common kind of chemical sensors in use:

  • Chemical field-effect transistor
  • Chemiresistor
  • Electrochemical gas sensor
  • Fluorescent chloride sensor
  • Hydrogen sulfide sensor
  • Nondispersive infrared sensor
  • pH glass electrode
  • Potentiometric sensor
  • Zinc oxide nanorod sensor

Gas sensor

Gas sensors are similar to the chemical ones, but are specifically used to monitor changes of the air quality and detect the presence of various gases. Like chemical sensors, they are used in numerous
industries such as manufacturing, agriculture and health and used for air quality monitoring, detection of toxic or combustible gas, hazardous gas monitoring in coal mines, oil & gas industries, chemical
laboratory research, manufacturing – paints, plastics, rubber, pharmaceutical & petrochemical etc.

Following are some common Gas sensors:

  • Carbon dioxide sensor
  • Breathalyzer
  • Carbon monoxide detector
  • Catalytic bead sensor
  • Hydrogen sensor
  • Air pollution sensor
  • Nitrogen oxide sensor
  • Oxygen sensor
  • Ozone monitor
  • Electrochemical gas sensor
  • Gas detector
  • Hygrometer

Smoke sensor

A smoke sensor is a device that senses smoke (airborne particulates & gases), and it’s level. They have been in use for a long period of time. However, with the development of IoT, they are now even more effective, as they are plugged into a system that immediately notifies the user about any problem that occurs in different industries.

Smoke sensors are extensively used by the manufacturing industry, HVAC, buildings, and accommodation infra to detect fire and gas incidences. This serves to protect people working in dangerous environments, as the whole system is much more effective in comparison to the older ones.

Common Types of Smoke Sensors
Smoke sensors detect the presence of Smoke, Gases and Flame surrounding their field. It can be detected either optically or by the physical process or by the use of both the methods.

Optical smoke sensor (Photoelectric):

Optical smoke sensor used the light scatter principle trigger to occupants.
Ionization smoke sensor: Ionization smoke sensor works on the principle of ionization, kind of chemistry to detect molecules causing a trigger alarm.

IR sensors

An infrared sensor is a sensor that is used to sense certain characteristics of its surroundings by either emitting or detecting infrared radiation. It is also capable of measuring the heat being emitted by objects.

They are now used in a variety of IoT projects built by IoT development companies, especially in Healthcare as they make monitoring blood flow and blood pressure simple. They are even used in a wide array of regular smart devices such as smartwatches and smartphones as well.

Other common use includes home appliances & remote control, breath analysis, Infrared vision (i.e. visualize heat leaks in electronics, monitor blood flow, art historians to see under layers of paint), wearable electronics, optical communication, non-contact based temperature measurements, automotive blind-angle detection.

Their usage does not end there, they are also a great tool for ensuring high-level security in your home. Also, their application includes environment checks, as they can detect a variety of chemicals and
heat leaks. They are going to play an important role in the smart home industry, as they have a wide range of applications.

Level sensors

A sensor which is used to determine the level or amount of fluids, liquids or other substances that flow in an open or closed system is called Level sensor.

Like IR sensors, level sensors are present in a wide array of industries. They are primarily known for measuring fuel levels, but they are also used in businesses that work with liquid materials. For example, the recycling industry, as well as the juice and alcohol industry rely on these sensors to measure the number of liquid assets in their possession.

The best use cases of the level sensor are fuel gauging & liquid levels in open or closed containers, sea level monitoring & Tsunami warning, water reservoirs, medical equipment, compressors, hydraulic reservoirs, machine tools, beverage and pharmaceutical processing, high or low-level detection, etc.

This helps better streamline their businesses, as sensors collect all the important data at all times. With the use of these sensors, any product manager can precisely see how much liquid is ready to be distributed and whether the manufacturing should be stepped up.

There are two basic level measurement types:

Point level sensors: Point level sensors usually detect the particular specific level and respond to the user if the sensing object is above or below that level. It is integrated into single device to get an alarm or trigger
Continuous level Sensor: Continuous level sensors measure liquid or dry material levels within a specified range and provide outputs which continuously indicate the level. The best example of it is fuel level display in the vehicle.
Image sensors

Image sensors are instruments which are used to convert optical images into electronic signals for displaying or storing files electronically.

The major use of image sensors is found in digital cameras & modules, medical imaging and night vision equipment, thermal imaging devices, radar, sonar, media houses, and Biometric & IRIS devices.

Two main types of sensors are used in:

  • CCD (charge-coupled device), and
  • CMOS (complementary metal-oxide semiconductor) imagers.

Although each type of sensor uses different technology to capture images, both CCD and CMOS imagers use metal-oxide semiconductors, having the same degree of sensitivity to light, and no inherent quality difference

An average consumer would think that this is a regular camera, but even though this is not far from the truth, image sensors are connected to a wide range of different devices, making their functionality much better.

One of the best-known uses includes the car industry, in which imagery plays a very important role and a automotive software development company would heavily rely on it to bring automation. With these sensors, the system can recognize signs, obstacles and many other things that a driver would generally notice on the road. They play a very important role in the IoT industry, as they directly affect the progress of driverless cars.

They are also implemented in improved security systems, where images help capture details about the perpetrator.

In the retail industry, these sensors serve to collect data about customers, helping businesses get a better insight into who is actually visiting their store, race, gender, age are only some of the useful parameters that retail owners get by using these IoT sensors.

Motion detection sensors

A motion detector is an electronic device which is used to detect the physical movement (motion) in a given area and it transforms motion into an electric signal; motion of any object or motion of human

Motion detection plays an important role in the security industry. Businesses utilize these sensors in areas where no movement should be detected at all times, and it is easy to notice anybody’s presence with these sensors installed.

A software development firm or IoT company will use these sensors primarily for intrusion detection systems, automatic door control, boom barrier, smart camera (i.e motion-based capture/video
recording), toll plaza, automatic parking systems, automated sinks/toilet flusher, hand dryers, energy management systems(i.e. Automated Lighting, AC, Fan, Appliances Control), etc.

On the other hand, these sensors can also decipher different types of movements, making them useful in some industries where a customer can communicate with the system by waving a hand or by performing
a similar action. For example, someone can wave to a sensor in the retail store to request assistance with making the right purchase decision.

Even though their primary use is correlated with the security industry, as technology advances, the number of possible applications of these sensors is only going to grow.

Following are key motion sensor types widely used:

  • Passive Infrared (PIR): It Detects body heat (infrared energy) and the most widely used motion sensor in home security systems.
  • Ultrasonic: Sends out pulses of ultrasonic waves and measures the reflection off a moving object by tracking the speed of sound waves.
  • Microwave: Sends out radio wave pulses and measures the reflection off a moving object. They cover a larger area than infrared & ultrasonic sensors, but they are vulnerable to electrical interference and more expensive.

Accelerometer sensors

An accelerometer is a transducer that is used to measure the physical or measurable acceleration experienced by an object due to inertial forces and converts the mechanical motion into an electrical output. It is defined as rate of change of velocity with respect to time.

These sensors are now present in millions of devices, such as smartphones. Their uses involve the detection of vibrations, tilting, and acceleration in general. This is great for monitoring your driving
fleet, or using a smart pedometer.

some instances, it is used as a form of anti-theft protection, as the sensor can send an alert through the system if an object that should remain stationary is moved. They are widely used in cellular & media devices, vibration measurement, automotive control and detection, free fall detection, aircraft and aviation industries, movement detection, sports academy/athletes behavior monitoring, consumer electronics, industrial & construction sites etc.

There are various kinds of accelerometers and following are few mainly used in IoT projects:

  • Hall-effect accelerometers: Hall-effect accelerometers are using Hall principle to measure the acceleration, it measures the voltage variations caused by changes in a magnetic field
  • around them.
  • Capacitive accelerometers: Capacitive accelerometers sensing output voltage dependents on the distance between two planar surfaces. Capacitive accelerometers are also less prone to noise and variation with temperature.
  • Piezoelectric accelerometers: Piezoelectric sensing principle is working on the piezoelectric effect. Piezo-film based accelerometers are best used to measure vibration, shock, and pressure.

Each accelerometer sensing technology has its own advantages and compromises. Before selecting, it’s important to understand the basic differences of the various types and the test requirements.

Gyroscope sensors

A sensor or device which is used to measure the angular rate or angular velocity is known as Gyro sensors, Angular velocity is simply defined as a measurement of speed of rotation around an axis. It is a device used primarily for navigation and measurement of angular and rotational velocity in 3-axis\ directions. The most important application is monitoring the orientation of an object.

Their main applications are in car navigation systems, game controllers, cellular & camera devices, consumer electronics, robotics control, drone & RC control helicopter or UAV control, vehicle
control/ADAS and many more.

There are several different kinds of gyro sensors which are selected by their working mechanism, output type, power, sensing range and environmental conditions.

Rotary (classical) gyroscopes
Vibrating Structure Gyroscope
Optical Gyroscopes
MEMS(micro-electro-mechanical systems) Gyroscopes

These sensors are always combined with accelerometers. The use of these two sensors simply provides more feedback to the system. With gyroscopic sensors installed, many devices can help athletes improve the efficiency of their movements, as they gain access to the athletes movement during sports activities.

This is only one example of its application, however, as the role of this sensor is to detect rotation or twist, its application is crucial for the automation of some manufacturing processes.

Humidity sensors

Humidity is defined as the amount of water vapour in an atmosphere of air or other gases. The most commonly used terms are “Relative Humidity (RH)

These sensors usually follow the use of temperature sensors, as many manufacturing processes require perfect working conditions. Through measuring humidity, you can ensure that the whole process
runs smoothly, and when there is any sudden change, action can be taken immediately, as sensors detect the change almost instantaneously.

Their applications and use can be found in Industrial & residential domain for heating, ventilating, and air conditioning systems control. They can also be found in Automotive, museums, industrial spaces
and greenhouses , meteorology stations,Paint and coatings industries, hospitals & pharma industries to protect medicines

Optical sensors

A sensor which measures the physical quantity of light rays and convert it into electrical signal which can be easily readable by user or an electronic instrument/device is called optical sensor.

Optical sensors are loved by IoT experts, as they are practical for measuring different things simultaneously. The technology behind this sensor allows it to monitor electromagnetic energy, which includes, electricity, light and so on.

Due to this fact, these sensors have found use in healthcare, environment monitoring, energy, aerospace and many more industries. With their presence oil companies, pharmaceutical companies and mining companies are in a much better position to track environmental changes while keeping their employees safe.

Their main use can be found in ambient light detection, digital optical switches, optical fibres communications,due to electrical isolation best suited for oil and gas applications, civil and transportation fields, high speed network systems, elevator door control, assembly line part
counters and safety systems.

Following are key type of optical sensors:

  • Photodetector: It uses light sensitive semiconductor materials like photocells,photodiodes or phototransistors to work as photodetector
  • Fiber Optics: Fibers optics carry no current, So its immune to electrical & electromagnetics interference and even in damaged condition no sparking or shock hazard happens.
  • Pyrometer: It estimates the temperature of an object by sensing the color of the light and Objects radiate light according to their temperature and produce same colors at same temperature.
  • Proximity & Infrared: Proximity use light to sense objects nearby and Infrared are used where visible light would be inconvenient.

It is clear that IoT has become incredibly popular, and current trends show that it is the future. It simply helps with automation of various processes, making these systems quite useful for both regular consumers and businesses.

We are yet to see the full potential this technology carries, as the whole platform is becoming smarter through the fusion of all the abovementioned sensors. When you consider the fact that all of the measured data is collected and can be analyzed, it is obvious that IoT is going to become even smarter in the future.

Leave a Reply

Your email address will not be published. Required fields are marked *