IoT Interview Questions

Dive into the world of Internet of Things (IoT) with 'IoT Interview Questions.' This blog serves as your comprehensive guide for acing IoT-related interviews, offering a diverse array of questions and detailed answers. Whether you're an IoT enthusiast, a solutions architect, or an aspiring IoT developer, our resource covers IoT concepts, protocols, security, and practical applications. Prepare with confidence and explore the transformative potential of IoT in the connected world of technology.

1. What is IoT?

The Internet of Things (IoT) refers to the network of physical objects or "things" embedded with sensors, software, and connectivity to exchange data with other connected devices and systems over the internet.

2. Explain the components of an IoT system.

An IoT system typically includes devices or sensors, connectivity, data processing, and an application or user interface. Devices collect data, transmit it through a network, and the data is processed for meaningful insights.

3. What are different types of sensors in IoT?

In recent years, Internet-of-Thing sensors have gained importance for enhancing productivity, lowering costs, and improving worker safety. Sensors are devices that detect changes in the environment condition and act accordingly. They detect specific types of conditions (such as light, heat, sound, distance, pressure, presence or absence of gas/liquid, etc.) in the physical world and then generate a signal (usually an electrical signal) as a measure of their magnitude. Sensors commonly used in IoT systems include: 

  • Temperature sensors
  • Pressure sensor
  • Motion detection sensors
  • Gas sensor
  • Proximity sensor
  • IR sensors
  • Smoke Sensor, etc.

4. Write some of the most common IoT applications.

Following are some of the most common real-world applications of IoT: 

  • Smart Homes: Smart homes are one of the most practical applications of IoT. Though IoT is applied in smart homes at various levels, the best one combines intelligent systems and entertainment. Example: Set-top box that allows you to record shows from remote, an automatic lighting system, a smart lock, etc.
  • Connect Health: Connected health systems allow for real-time monitoring and patient care. Patient data assists in better medical decisions. Also, IoT improves the power, precision, and availability of current devices.
  • Wearables: Wearable devices have emerged as one of the earliest industries to deploy the IoT at scale. Various wearable devices are available today, such as Fit Bits, heart rate monitors, and smartwatches.
  • Connected Cars: Connected cars use internet connectivity and onboard sensors to optimize their operation, maintenance, and passengers' comfort. Some of the leading automakers are working on bringing the next revolution to the car industry, including Tesla, BMW, Apple, and Google.
  • Hospitality: By applying IoT to the hotel industry, a higher level of service quality is achieved. Various interactions can be automated by using electronic keys that are sent directly to the mobile devices of guests. Therefore, the IoT technology enables integrated applications to manage activities such as tracking guests' locations, sending offers or information about interesting activities, placing orders for room service or room orders, and automatically charging the room account.
  • Farming: A variety of tools are being developed to deal with Drip Irrigation, understanding crop patterns, Water Distribution, drones for farm surveillance, etc. Farmers will be able to increase yields and address concerns using these methods.

5. Explain how IoT works.

Artificial Intelligence is at the core of IoT devices. The IoT consists of multiple components: sensors, a cloud component, data processing software, and cutting-edge user interfaces.   

IoT systems consist of sensors/devices connected to the cloud via some form of connectivity. A Raspberry Pi equipped with a quadcore processor can be used as an "Internet gateway" for IoT devices. It is a card-sized computer using which you can control outputs with GIPO (general purpose input/output) pins as well as collect data about real-world conditions using sensors. A sensor gathers live data from the surrounding environment and sent to a cloud infrastructure. Once the data reaches the cloud, the software can process it and decide what action to take, such as sending an alert or automatically adjusting the sensors/devices without user intervention.

A user interface is used if user input is required or if they want to check in on the system. Adjustments made by the user are then sent inversely through the system - from the user interface to the cloud, and from the cloud back to the sensors/devices to make changes. As a result, a highly reactive and intuitive device is created which greatly increases automation. 

6. What do you mean by PWM (Pulse Width Modulation)?

Have trouble adjusting the brightness of the LEDs in your project? Changing the voltage of the power supply directly in the circuit isn't easy. In that case, you can use Pulse Width Modulation (PWM).  

Pulse Width Modulation (PWM), also referred to as PDM (Pulse Duration Modulation) refers to changing the amount of power that is delivered to a device. PWM is a technique for generating an analog signal from a digital source and is an efficient way to control the amount of energy delivered to a load without wasting any energy. PWM regulates voltage and is therefore used to control brightness in Smart Lighting Systems and also to control motor speed. 

7. Explain Shodan.

Shodan (Sentient Hyper-Optimized Data Access Network) is a search engine similar to Google, but it does not search for websites, but rather maps and information about internet-connected devices/systems. Shodan is sometimes referred to as an IoT search engine. To put it simply, Shodan is an IoT tool used to identify Internet-connected devices. It keeps track of all the machines with direct Internet access. 

Cybersecurity experts use Shodan as a tool to protect individuals, companies, and even public utilities against cyber-attacks. Shodan lets you search for any internet-connected device, and it will tell you if it is publicly available or not. 

8. Name some of the most suitable databases for IoT.

The following databases are suitable for IoT: 

  • InfluxDB
  • Apache Cassandra
  • RethinkDB
  • MongoDB
  • Sqlite

9. Explain sharding.

Sharding is the process of splitting very large databases into smaller, faster, and easier to manage pieces, called data shards. A shard is a small portion or chunk of a large data set. The principle of sharding is to split a logical dataset into multiple databases in order to store it more efficiently. In the case of a dataset that cannot be stored in a single database, sharding is necessary. 

10. State the difference between IoT and M2M.

IoT (Internet of Things): It is referred to as a network comprised of interconnected physical objects that are capable of collecting and exchanging data. These devices contain embedded systems (software, electronics, networks, and sensors) that are able to collect data about the surrounding environment, transmit data over a network, respond to remote commands, or take actions based on data collected. The Internet of Things (IoT) is a subset of M2M (Machine to Machine) technology. In IoT, two machines communicate without human intervention, making it a part of M2M. 

M2M (Machine to Machine): In M2M, devices communicate with each other directly via wired or wireless channels, without any human interaction. It enables devices to communicate and share data with each other without relying on the internet. Several applications of M2M communications are available, including security, tracking, and tracing, manufacturing, and facility management. 

It is a network of connected devices (via the Internet) that have the ability to collect, process, and transmit data automatically without human intervention.    It allows two or more machines to communicate directly and perform certain tasks without requiring human intervention.  
In addition, IoT enables objects to interact with the internal and/or external environments, thereby influencing their decision-making. The M2M model exhibits some degree of intelligence. Devices capture data and share it with other connected devices, forming an intelligent network.
It facilitates cloud-based communication.    End-to-end communication between devices/machines is supported.  
In order to improve the end-user experience, data is shared between other applications.   Only parties communicating with each other have access to the data. 
Internet access is usually required for devices to communicate and share data.    Devices don't usually require an Internet connection for communication.  
Many machines are able to communicate over the internet.   The communication between machines is limited to one at a time.   
Open API integrations are supported.  Open API integrations are not supported.  
A number of Internet protocols are used, including HTTP, FTP, and Telnet.  Communication technologies and traditional protocols are used. 

11. Explain WoT (Web of Things).

WoT (Web of Things) is an advancement of the Internet of Things by integrating smart things not only with the Internet (network) but with the Web Architecture (application). In short, the Web of Things (WoT) is aimed at facilitating the interoperability and usability of IoT.  It is a web standard for enabling communication between smart devices and web applications.

12. Explain Bluegiga APX4 protocol.

The Bluegiga APx4 is a low power wireless System-on-Module (SOM). It's an ideal development platform for developing gateways since it's equipped with integrated Wi-Fi, Bluetooth 4.0, ARM, and Linux. Wireless and Bluetooth low energy (BLE) can be used together without interference as they are compliant with coexistence protocols. Bluegiga Apx4 supports both Wi-Fi and Bluetooth, and its 450mhz Arm9 processor provides smooth performance. 

13. State the difference between IoT and IIoT.

IoT (Internet of Things): Any device that can connect to the internet and transfer data to a remote data server is termed the Internet of Things (IoT). 

IIoT (Industrial Internet of Things): In the case of IoT devices used for industrial purposes, these devices are referred to as Industrial Internet of Things (IIoT). IIoT is the subset of IoT.  

Difference between IIoT and IoT-

It supports industrial-oriented applications such as manufacturing, power plants, oil & gas, etc.  It supports customer-oriented applications such as wearables to robots and machines. 
The focus is on large scale networks.   The focus is on small scale networks. 
Both wired and wireless communication methods are utilized.  Typically, wireless communication methods are utilized. 
A large amount of data is handled.  It can handle data ranging from medium to high. 
This is a B2B (business-to-business) and is designed to increase efficiency and safety at production facilities.  This is B2C (business-to-consumer) and is designed to make the lives of consumers more convenient.  

14. Explain the meaning of Arduino.

Arduino is an open-source platform for building electronics projects using easy-to-use hardware and software. A microcontroller is the common feature of all Arduino boards. The microcontrollers on board are capable of reading inputs (e.g., light on a sensor, an object near a sensor) and converting them to outputs (drive a motor, ring an alarm, turn on an LED, display information on an LCD). It is possible to connect multiple devices and exchange data in real-time between them. It is also possible to monitor them remotely using a simple interface. 

15. What do you mean by Raspberry Pi?

Raspberry Pi is a card-sized computer with features like General Purpose Input Output (GPIO) pins, WiFi, and Bluetooth that allow it to communicate, control, and connect to other external devices. Combining IoT applications with Raspberry Pi helps businesses embrace technology more effectively. 

16. Explain sketch in Arduino and how will you reduce the size of sketch.

Arduino refers to a program as a sketch. In other words, it is a bit of code that is uploaded to and executed on an Arduino board. It is possible to reduce the size of the sketch by removing unnecessary libraries from the code and making it simple and short. 

17. What is GPIO (General Purpose Input/Output)?

GPIO (General-purpose input/output) is a standard interface using which Raspberry Pi and other microcontrollers can connect to external electronic components/devices. These are basically programmable pins on an integrated circuit or board that allow digital input or output signals to be controlled programmatically.

18. State different between Arduino and Raspberry Pi.

We can use many different kinds of controller boards for our hardware projects. Arduino and Raspberry Pi are among the most popular. 

Difference between Arduino and Raspberry Pi-

Arduino Raspberry Pi
Arduino is an open-source, programmable USB microcontroller.  It is a microprocessor-based minicomputer (SBC).  
Arduino boards have a microcontroller that includes a CPU, RAM, and ROM. The Arduino Board has additional hardware for power supply, programming, and IO (Input/Output) connectivity.    The Raspberry Pi SBC (Single board computer) comes with everything you need to run a computer, from a processor, memory, storage, graphics driver, to connectors.  
With Arduino, you can interface sensors and control LEDs and motors.  It works well for developing Python-based applications.   
It has a simple hardware and software architecture.   On the other hand, Raspberry Pi boards have a complex architecture.  
It is possible to build your own Arduino board using the open-source hardware and software files of Arduino.   Since the Raspberry Pi is not open-source, it cannot be used for this purpose.   
It is used to run one single task at a time.  It can perform several tasks at once such as running software, web browsing, doing programming, etc.. 

19. State difference between IoT and WSN (Wireless Sensor Network)?

WSN (Wireless sensor network): It uses a network of dedicated sensors to monitor and record the physical conditions of the environment and to organize the recorded data at one central location. WSN: Sensor nodes connected without a wire to gather data. 

IoT (Internet of Things): It is referred to as a network comprised of interconnected physical objects that are capable of collecting and exchanging data. These devices contain embedded systems (software, electronics, networks, and sensors) that are able to collect data about the surrounding environment, transmit data over a network, respond to remote commands, or take actions based on data collected. IoT: WSN + Any physical object (Thing) + IP address + Internet + App + Cloud computing + etc.… 

20. Explain IoT GE-PREDIX.

GE (General Electric) Predix is a software platform for collecting industrial instrument data. This platform enables industrial-grade analytics for operations optimization and performance management via a cloud-based PaaS (platform as a service). 

21. Name some of the wearable Arduino Boards.

The following wearable Arduino boards are available: 

  • Lilypad Arduino main board
  • Lilypad Arduino simple
  • Lilypad Arduino simple snap
  • Lilypad Arduino USB

22. Explain IoT asset tracking.

"Asset tracking" entails tracking a particular asset and its location, whether it's a hammer, an X-ray machine, a vehicle, a shipping crate, or even a person. How does the IoT fit in here? Rather than manually tracking assets like a supervisor filling out a form when the asset arrives at a specific location, IoT tracking systems use sensors and asset management software to track things automatically. The assets are fitted with sensors, which broadcast their location over the internet on a continuous or periodic basis, and the software displays this information for you to see. Different types of IoT asset tracking systems transmit location information differently, such as via GPS, Wi-Fi, or cellular networks.

23. Code Snippet: Basic IoT Device Code

// Sample IoT Device Code (Arduino)
#include <Wire.h>

void setup() {
    Wire.begin(); // Initialize the I2C communication

void loop() {
    // Read sensor data
    int sensorValue = analogRead(A0);

    // Send data to the cloud


24. Online Resources:

Published On: 2024-01-31