Generally speaking, a sensor is a device that is able to detect changes in an environment. By itself, a sensor is useless, but when we use it in an electronic system, it plays a key role. A sensor is able to measure a physical phenomenon (like temperature, pressure, and so on) and transform it into an electric signal.The Internet of Things is one of the most important and promising technological topics today. Some market researchers estimate that there are more than 20 billion connected devices and counting. Around us, there are smartphones, wearables, and other devices, all of which use sensors. Nowadays, sensors play an important role in our everyday life and in IoT. Sensors monitor our health status (e.g. a heartbeat), air quality, home security, and are widely used in the Industrial Internet of Things (IIoT) to monitor production processes. For these reasons, it is important to know how they work and how we can use them to acquire information.
The development of prototyping boards and the low price of sensors allow us easily use them in IoT projects. There are several prototyping boards on the market, suited for different projects depending on features and specifications. In this context, we will consider the two most popular boards: the Arduino Uno and Raspberry Pi 2.
Sensors can be grouped using several criteria:
Passive or Active. Passive sensors do not require an external power source to monitor an environment, while Active sensors require such a source in order to work.
Another classification is based on the method used to detect and measure the property (mechanical, chemical, etc.).
Analog and Digital. Analog sensors produce an analog, or continuous, signal while digital sensors produce a discrete signal.
Let’s take a look at some of the key sensors, extensively being used in the IoT world.
1. Temperature Sensors
By definition, “A device used to measure the 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 a 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 the soil is crucial for crop growth. This helps with the production of plants, maximizing the output.
Followed are some sub-categories of Temp Sensors:
A device that detects the presence or absence of a nearby object, or properties of that object, and converts it into a signal which can be easily read by the 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 checking parking availability in places such as malls, stadiums or airports.
Following are some of the Proximity Sensors sub-categorised:
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 easily detects any fluctuation or drops in pressure.
Water quality sensors are used to detect the water quality and Ion monitoring primarily in water distribution systems.
Water is practically used everywhere. These sensors play an important role as they monitor the quality of water for different purposes. They are used in a variety of industries.
Following is a list of the most common kind of water sensors in use.
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 a space station, pharma industries and laboratory etc.
Following are most common kind of chemical sensors in use:
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:
A smoke sensor is a device that senses smoke (airborne particulates & gases) and its 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 Type 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.
An infrared sensor is a sensor which 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 the objects.
They are now used in a variety of IoT projects, especially in Healthcare as they make monitoring of 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 here; 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.
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 a 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.
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 to 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:
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 sensor is found in digital camera & modules, medical imaging and night vision equipment, thermal imaging devices, radar, sonar, media house, 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 with 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. 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 of which race, gender, age are some of the useful parameters that retail owners get by using these IoT 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 an object or motion of human beings.
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. These are primarily used in 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 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 for making the right purchase decision.
Even though their primary use is correlated with the security industry, as the technology advances, the number of possible applications of these sensors is only going to grow.
Following are key motion sensor types widely used:
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 the rate of change of velocity with respect to time.
These sensors are now present in millions of devices, such as smartphones. Their uses involve detection of vibrations, tilting and acceleration in general. This is great for monitoring your driving fleet or using a smart pedometer. In 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, movement detection, behavior monitoring in sports academy, consumer electronics, industrial & construction sites, aircraft and aviation industries, etc.
There are various kinds of accelerometers and following are few mainly used in IoT projects:
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.
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 the 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.
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 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 precise 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 can be found in the 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.
A sensor which measures the physical quantity of light rays and converts it into an electrical signal which can be easily readable by a user or an electronic instrument/device is called an 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:
It is clear that IoT has become incredibly popular, and current trends show that it is the future. It simply helps with the 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 above-mentioned 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.As IoT applications grow, so does the demand for sensors. There are a wide variety of sensors available. But for an IoT application, choosing the right sensor as well as the right IoT platform is important.
An IoT device is connected with other IoT devices, providing data through Internet transfer protocols. So the two main divisions in an IoT system are the network and IoT platform at the back-end and the sensors and actuators at the front-end.
Most of the IoT platforms are dependent on sensors. There are many IoT platforms available but two main IoT platforms that stand out are industrial and consumer. Both these platforms slightly differ in their applications and requirements. The industrial IoT platform must be stable, reliable and secure as the platform failure may cost millions of dollars or even lives. On the other hand, a failure in consumer IoT platform can be just an inconvenience to you.
However, there are some common parameters to be considered when choosing the best IoT platform for your application. Some of these parameters include reliability, stability, flexibility, security support, pricing model, mobile/web application support, ability to handle a number of connected products, data retention or backup when power or network connection fails, and the speed and time to launch the product.
Some of the IoT platforms are listed below.
It is an IoT platform backed by IBM’s hybrid cloud PaaS (platform as a service) development platform, the Bluemix. It features device management, secure communications, real-time data exchange, data storage and weather data service.
This IoT platform makes it a lot easier for developers to connect sensors for multiple applications ranging from automobiles to turbines to smart home light bulbs.
Its features include device shadowing, rules engine, identity registry and information monitoring.
It is one of the best IoT platforms. It is a set of modular cloud-based services that allow you to create anything from simple websites to complex applications.
It is one of the earliest IoT software platforms designed to build and run applications including aerospace, automotive, consumer products, industrial equipment and medical devices.
It offers new ways to manage and store data in the cloud and data centres. Its features include voice and data connectivity, SIM lifecycle management, IP session control, customisable billing and reporting.
It is a simplified way to go from prototype to production. The API allows to add and activate devices, check their status, monitor their usage, and perform other device connectivity management tasks through a REST API.
It offers users complete safety and reliability while storing the data. It is a flexible IoT platform based on open standards and open source. Its cloud services meet the requirements typical of IoT projects.
This integrated smart IoT platform provides the fastest path to secure and interoperable IoT products and services.
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