Widely used Sensors in IoT Development Industry

Sensors are the small electronic components which are integrated into smart devices surrounding us. Today every device we use has a sensor. For Example, a washing machine or a computer or mobile phones. But what exactly sensors are, have you ever thought?

 A sensor is an electronic component which is used to measure different inputs from the surroundings which are then converted into a human-readable format. The input can be anything from sound to temperature or humidity to N, P, K values, etc. These devices are embedded with different machines or devices to make them work accordingly. The data collected by the sensors is usually depicted in visual form via IoT dashboard.

Let’s talk about the most used sensors in the IoT Development Industry.

Humidity sensors

The humidity sensor is used for measuring the amount of moisture content available in the specimen, also used to determine the water vapours in the air or gas. The data collected by the humidity sensor are then converted into electrical signals which are further converted into human readable text. The size and functionality of humidity sensors vary depending upon its purpose. Some humidity sensors are embedded into larger systems and used for meteorological purposes, automobiles, medical equipment, HVAC, and manufacturing systems.  

Working of humidity sensor

The humidity sensor collects the information related to the amount of water vapour present in the air and detects changes in electrical current or temperature in the surroundings. Different humidity sensors work on different working principles to provide the humidity value. Capacitive humidity sensor has a pair of electrodes stuffed with hydroelectric dielectric which forms a small capacitor. A resistive humidity sensor works by collecting different resistance values. The resistance changes as the humidity changes.

iot humidity sensor

Types of humidity sensor

  1. Capacitive humidity sensor: Capacitive humidity sensors are used for measuring relative humidity and comprise two different roles for storing electric charge.
  2. Thermal humidity sensor: Thermal humidity sensors are mostly used for measuring the absolute humidity of a place.
  3. Resistive humidity sensor: The relative humidity sensor measures the electrical impedance of atoms by utilizing ions.

Applications of humidity sensor

  1. Soil Quality Monitoring system
  2. Humidity indicator device
  3. Refrigerator 
  4. Weather forecast
  5. Temperature monitoring
  6. Air pollution measuring system

Optical sensors

Optical sensors are designed for converting light rays into electronic signals and measure the physical value of light. Based on the kind of sensor, the data is translated into a readable format that is integrated into a measuring device. These sensors are particularly suited for contactless counting, protection for positioning of physical parts etc. Optical sensors are also used for measuring velocity, liquid level, temperature, chemical species, displacement, force radiation, electric and electrostatic field, strain, PH value, etc.

Working of Optical Sensor

The principle on which an optical sensor works is transmitting and Receiving light rays. The sensor converts light beams into electronic signals. In basic terms, the optical sensor is used to measure the light quantity physically. The result is then transmitted in the human-readable format. The measurements of the light beam differ based on the object type by which the light beam is reflected. The sensor can be used in various ways, which further categorise the sensors in 3 types.

  • Through-Beam Sensors
  • Retro-Reflective Sensors
  • Diffuse Reflection Sensors
IOT Optical sensor


  1. PHOTOCONDUCTIVE DEVICES: Coverts the change of incident light into the change of resistance.
  2. PHOTOVOLTAIC CELL: Converts incident light rays into voltage. 
  3. PHOTODIODES: Converts incident light rays into the current.
  4. PHOTOTRANSISTOR: Converts incident light rays into CURRENT WITH INTERNAL GAIN.

Applications of optical Sensor

  1. Ambient Light sensors in our phones
  2. Liquid Level Indicator
  3. Military and law enforcement
  4. Camera
  5. Biometric devices
  6. Biomedical equipment
  7. Photo sensing

Proximity sensors

The proximity sensor is a type of non-contact sensor that is used for recognizing the presence of an object when it enters the sensor field. Based on the kind of proximity sensor light, sound, electromagnetic field, infrared radiation is used for the detection of the target. Usually, proximity sensors are used in recycling plants, anti-aircraft systems, self- driving cars and smartphones. 

Working of proximity sensor

The proximity sensor is used to detect any object. The capacitive proximity sensor can detect any kind of object whereas the inductive proximity can only detect metal. A coil is present in the sensor which produces an electrical field which is generated by providing power supply to the circuit. Whenever any metal comes into proximity, an eddy current is generated which revolves around the object. As the distance between the sensor and metal object decreases, the eddy current increases and gives the signals. 

iot proximity sensor

Types of proximity sensor

The most common types of proximity sensors are capacitive sensors and inductive sensors.

  1. Capacitive sensors: These sensors are capable of detecting all kinds of objects that can store electrical charge.
  2. Inductive sensors: These sensors can only detect metal targets with the help of an electromagnetic field.

Applications of proximity sensor

  1. Blind stick 
  2. Mobile Phones
  3. Home automation system
  4. Automobiles
  5. Direction sensing device
  6. Recycling planar craft systems

Temperature sensors

Temperature sensors are devices that can measure the temperature of an object or surroundings and convert them into electronic data. Temperature sensors are used for keeping track of temperature changes of an item or place. There are different varieties of temperature sensors some require physical contact with the item for temperature measurement while others can detect the temperature indirectly.  

Working of Temperature Sensor

Temperature sensor works on the principle of determining temperatures through voltage across the diode terminals. The temperature rise is measured with the increase in voltage. The rise in temperature results in decreased voltage between the transistor terminal emitter and base present in the diode émitter. The vibrating wire temperature meter is designed on the principle that dissimilar metals have a different linear coefficient of expansion with temperature variation. The wire is specially built and known as encardio-rite vibrating wire.

Temperature sensing

Types of Temperature sensor

  1. Contact Type. As the name suggests, the contact type temperature sensor measures the rise or decrease in temperature by directly contacting the object.
  2. Non Contact type: The temperature rise or fall is measured and detecting the emitted heat radiation from the is required Source. No direct contact is needed for measuring the temperature.

Applications of Temperature sensor

Temperature sensors are being used in cooking appliances, apparatus, mobiles, and various other types of instruments. Some applications of temperature sensor are:

  1. Temperature Guns at entry
  2. Heating, ventilation, and air conditioning (HVAC)
  3. Home appliances
  4. Computers
  5. Electrical radiators warmers
  6. Motorsport vehicles

IR Sensors

An infrared sensor or IR sensor as it is popularly known is a type of electronic component used for detecting and measuring infrared radiation in the environment. Typically infrared radiations are not seen by the human eye because of its longer wavelength compared to visible light. Any object emitting heat with temperatures above 5 Kelvin is an emitter of infrared radiation.

Working of IR sensor

Working of IR sensor is based on two integrated components, i.e. IR transmitter and IR receiver. The IR transmitter transmits infrared Radiations which are not visible to humans. These radiations are then detected by the IR receiver. The IR transmitter comes in the form of LEDs whereas the IR receiver is in the form of a photodiode. In simple terms, the IR LED transmits rays which reflect after coming in contact with an object. The reflective rays are received by a photodiode and complete the working of the IR sensor.

IR Sensor

Types of IR sensor

Infrared sensors are of two types:

  1. Active IR sensors: Active sensors can detect as well as emit infrared radiation. Active infrared sensors are used as proximity sensors in obstacle detection.
  2. Passive IR sensor: On the other hand, passive infrared sensors can only identify infrared radiation from a source. Motion-based detection systems typically use passive infrared sensors.

Applications of IR sensor

  1. Night vision camera
  2. IR imaging systems
  3. Infrared tracking
  4. Radiation thermometer  
  5. Gas detectors
  6. Flame monitors

Electrochemical sensors

Electrochemical sensors are used for the detection of toxic gases and oxygen in the surroundings; it is used for measuring the concentration of harmful gases in a particular place. Detection of gases is done through oxidation and reduction reactions that generate positive or negative current flow in external circuits. 

Working of Electrochemical sensors

Electrochemical sensors comprise electrodes, namely the working electrode, a counter electrode, and the reference electrode placed inside a sensor housing immersed in an electrolyte. These sensors work by diffusion of gases that result in the flow of electrons from the working electrode to the counter electrode via the external circuit. The reduction reaction causes an alternative flow of electrons; the concentration of current generated is directly proportional to the volume of gas.

Electochemical Sensors

Types of Electrochemical sensors

  1. Potentiometric Sensor: In potentiometric sensors, a nearby equilibrium is established in the sensor port, at which both the electrode or membrane potential is quantified, and data regarding the composition of a sample is obtained in the possible gap between two electrodes.
  2. Amperometric Sensor: The Amperometric Sensor exploits the usage of a potential applied between a benchmark and a working electrode, to induce the oxidation or loss of an electroactive species; the consequent current is measured. 
  3. Conductometric sensors: The conductometric sensors are included with the measurement of conductivity in a set of frequencies.

Applications of Electrochemical sensors

  1. Forensic drug analysis
  2. Medical diagnostics
  3. Food Monitoring
  4. Water quality analysis
  5. Environmental monitoring

Ultrasonic Sensors

Ultrasonic sensors are widely used in the IoT industry for measuring the distance of an object with the help of ultrasonic sound waves. The ultrasonic sound waves get reflected by the object which is then converted into electrical signals.

Working of Ultrasonic sensor

Ultrasonic sensor has two main components i.e transmitter and receiver. The transmitter transmits ultrasonic soundwaves which strike the object and get reflected. The reflected rays are catched by the receiver on the other hand and converted into electrical signals. The soundwaves sent by the ultrasonic sensors are not audible to human ears. The distance of the object is calculated with respect to the time taken by the sound waves to reflect back and received by the receiver. 

ultra sensor iot

Types of ultrasonic sensors

  1. Diffuse Proximity sensor: The ultrasonic sensors are used for measuring proximity of the object. The proximity type of ultrasonic sensor has a sonic transducer. The transducer sends numerous ultrasonic signals and measures the distance by hearing the sound of waves when returning after reflection.
  2. Retro -reflective sensor: The object is kept on a specified distance. The name retro reflective is given because the sensor sends a series of sound waves which are reflected by fixed position reflectors.
  3. Beam sensor: The Beam ultrasonic sensor has two different holders for transmitter and receiver. The continuous sound Waves are transmitted by the transmitter holder and received continuously by the receiver and the holder. Whenever an object comes in between the transmitter and receiver, the sonic beam disrupts. The disrupting is taken, as input for distance measurement or to find the intruder.

Applications of ultrasonic sensors

  1. Self Parking automobiles
  2. Obstacles detectors
  3. Robotics
  4. Medical equipments
  5. Anti collision detection
  6. Intrusion Detection

Micro-Electromechanical system

The microelectromechanical system is a technology associated with the manufacturing of microscale devices like Sensors, Transducers, Actuators, Gears, Pumps, Switches etc. If a Sensor is designed and manufactured using the MEMS Technology, then it is called a Micromachined Microsensor, or merely a MEMS Sensor Micro-Electromechanical system (MEMS) sensors fulfil a variety of purposes in various industries. These are high precision inertia sensors.

Working of Micro-Electromechanical system

The MEMS is composed of chip technology suspended between capacitive plates. When the sensor is tilted, the change in capacitance is measured as the difference made by suspended mass is detected. This can be measured like an alteration within capacitance. The signal could be changed to produce a stable output signal in digital.

micro electromechanical system

Types of Microelectromechanical system

  1. Accelerometer: Used for electronic stability
  2. Magnetometer: Use for direction control
  3. Pressure sensor: Used to monitor pressure.
  4. Airflow sensor: used to measure airflow

Applications of Microelectromechanical system

  1. Automotive
  2. Chemical and Pharmaceutical
  3. Industrial Automation and Manufacturing
  4. Defence, Space and Aeronautical
  5. Environmental and Health Sciences
  6. Wearables

Acoustic wave sensors

Acoustic wave sensor as the name suggests is the sensor which detects acoustic waves. According to the changes in waves, the change in velocity and amplitude can be detected.

Working of Acoustic Sensor

Acoustic sensors are designed for the detection of acoustic waves that can travel through a material or surface. Changes in the characteristics of the wave are measured and will affect the amplitude and velocity. Velocity changes are recorded by measuring phase characteristics and frequency of the sensor related to the physical quantity. Acoustic waves have differences in their velocities and direction, due to the medium of propagation and boundary conditions sensitivity of acoustic sensors varies due to several factors. 

Types of Acoustic Sensors

  1. Bulk wave sensor: Bulk acoustic wave sensors divide the surface energy through the bulk material to the other surface. 
  2. Surface wave sensor: Surface acoustic sensor focuses the surface energy on the surface itself to make it more sensitive.

Applications of Acoustic Sensor

The telecommunication industry is the largest consumer of acoustic sensors that are used as bandpass filters. Other applications of acoustic sensors include:

  1. Medical devices
  2. Commercial and industrial machinery
  3. Automobiles


The area of IoT devices is vast and spread to the core of our lives. However, without sensors, it is impossible to think about these devices. Therefore as a conclusion, we can say that sensors are a pillar of the smart technology industry. 


PsiBorg Technologies is an end-to-end IoT solution provider, and hence we love to play with sensors. Are you looking for consultation regarding these sensors or want someone to assist you in making a new smart solution? If yes, then let’s connect and find the way out to change the world with this fantastic technology called IoT and its building blocks, i.e. sensors.

Leave a comment