Top Sensor Types That Are Being Used in IoT

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The Internet of Things (IoT) is a system of interrelated computing devices, mechanical and digital machines, objects, animals or people that are provided with unique identifiers and the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction.

If your reaction after reading the above definition was “um… what did I just read?”, don’t sweat!

There are many who share the same opinion. For beginners, taking so much technical mumbo-jumbo naturally would be difficult. Instead, let us carefully explore what the IoT is and what makes it unique and efficient, without too many technical terminologies.

You might be seeing this post on a desktop or your mobile phone with the help of the internet. So, your device is connected with the internet. That’s pretty much what IoT entails; taking all the devices of the world and connecting them to the internet so that they can both send and receive data.

This example might you better understand it.

Imagine you are driving back home from work after a tiresome day, 3 days before Christmas. Bath before you get home, you want the water to be warm in your shower. Also, it’s already sundown, so you would prefer that the lights and decorations around the house are lit. Imagine, both things have their sensors connected to the internet which is also connected to you.

All you need to do is just click on your mobile screen and the water in your bathroom will become warmer and with another click, you can simply turn on the lights on your front porch.

Essentially, this technology brings together many devices where their sensors are connected to the internet to receive and send information. If you know about Google cars that can judge distances with their sensitive cameras and sensors, that’s an example of IoT as well. It can vary from checking water quality to Infra-Red sensors.

To learn more about IoT and how it works, try the “Raspberry Pi and the Internet of Things” course. The course contains 7 hours of video, that covers over 8 sections. They include the essentials of IoT, Pis Academy, coding with Python, Physical computing with Raspberry pi, and much more.

Now let us take a closer look at some of the popular sensors known in the IoT-sphere.

#1. Sensors to Judge Proximity or Distances


The example of Google cars or autonomous vehicles is an excellent example of the use of proximity sensors. But also, it is used in the retail sector as well. They can detect the motion and co-relation between the customer and product they might be willing to purchase.

Also, they are used in car parking spots to check the availability of space to park your vehicle.

Currently, we have four main types of proximity sensors.

Ultrasonic– These sensors act much like a radar or sonar technology, in order to detect the presence of objects in the nearby vicinity.
Photoelectric– Created out of light-sensitive parts that use a beam of light to the presence of an object.
Inductive– It is used to search metallic objects using an electromagnetic field or an electromagnetic radiation beam.
Capacitive– It can detect both metallic and non-metallic objects. It can sense very minuscule objects through a large portion of the target.

#2. Sensors for Temperature

This device measures the amount of heat energy that allows detecting a physical change in temperature from a particular source. This later converts the data for a device or user. With the increase of sensors, they are now available on multiple devices. In the past, these would generally be in ACs, refrigerators, and devices as such. But with IoT, they have spread into more fields pertaining to agriculture and manufacturing. In agriculture, the soil’s temperature is vital to the growth of crops, while checking the optimal temperature for a device to function efficiently.

They also have further sub-categories.

Thermistors– It changes its physical resistance with the change in temperature.
Thermocouples– They measure any sudden change in voltage.
Resistors Temperature Detectors– Resistance of the device is directly proportional to the temperature.
Infrared– It detects a portion of the infrared emitted and sensing its intensity. It can also measure the temperature of gasses.

#3. Chemical Sensors


The purpose of this is to indicate any changes in the composition of any liquid or any change in the atmospheric gasses in the given area. One example of it would be in cities where to keep a check on the air quality or to check the contents of the drinking water can be measured by it. These are vital in such cases.

They are even used in areas to check radiation as well as the changes in the environment after an accidental or intentional exposition. They are imperative to a person’s safety.

There are many common chemical sensors that are used.

Chemical Field-Effect Resistor
pH Glass Electrode
Zinc Oxide Nano Sensors
Potentiometric Sensors
Fluorescent Chloride Sensor

#4. Sensors for Testing Water Quality

It is used mainly for ion monitoring and keep a check on the water quality. This is especially helpful in big cities where clean and safe drinking water is needed 24X7.

They too have many common sub-groups.

TOC or Total Organic Carbon sensor– It measures the quantity of organic Carbon in the water.
Chlorine Residual Sensor– Chlorine is used as a disinfectant in water but much of it can hamper many organs in a human body. So, properly supervising the quantity of Chlorine helps to maintain a healthy amount of it in the water.
PH Sensor– It detects the acidity present in the water or the amount of alkali.

#5. Image Sensors

They are tasked with converting optical images into electronic signals to have it stored and displayed on your device. They are used in digital cameras, medical imaging, media house, radars, sonar, and such devices.

There are two types of sensors pertaining to this category.

Charge-Couple Device
Complementary Metal-Oxide-Semiconductor

#6. Motion Detection Sensors

bank safe

If you have seen any movie with the classic “steal the jewel from the bank”, you might be familiar with a spy using the most flexible moves to evade the surrounding web of laser lights and to steal it. And if they are caught in any of the laser beams, a bell goes out alerting the authorities of possible theft.

The sensor converts the detection of physical movement in a given area into electric signals. These motions can be of any animate or inanimate objects.

There are many main motion sensors used widely.

Ultrasonic– Sends out a wave of ultrasonic waves and receives it back measuring the reflection.
Microwave– It is used to send out radio-wave pulses to measure the reflection from an object in motion.

#7. Gyroscope Sensors

It measures the angular velocity and angular rate of an object. It is mainly used to measure and analyze the angular and rotational velocity of an object in a 3D plane. They are mainly found in many car navigation systems, mobile devices, drones and helicopters, and consumer electronics of many kinds.

There are a few popular gyro sensors.

Optical Gyroscope
Vibrating Structure Gyroscope
Micro-Electro-Mechanical System Gyroscope
Rotary Gyroscope


IoT brings with itself numerous benefits and transforms our lives for the better. But, with so many sensors and access points, the threat of attacks on your systems can also take place.

If you want to learn more about security to protect your personal devices, you can try out the “Cyber Security For Normal People: Protect Yourself Online” online course. The course comes with 1.5 hours of video that covers 7 sections with topics such as multi-factor authentication, Google two-factor authentication, Encryption and many more.

I hope you have found this article very informative and if you would like to share any feedback, let us know in the comments below.


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