Here are IoT interview questions for fresher as well as experienced candidates to get their dream job.

1) What is the Internet Of Things (IoT)?

Internet of Things (IoT) is a network of physical objects or people called "things" that are embedded with software, electronics, network, and sensors that allow these objects to collect and exchange data. The goal of IoT is to extend to internet connectivity from standard devices like computer, mobile, tablet to relatively dumb devices like a toaster.

2) Explain Raspberry Pi

Raspberry Pi is a computer which is capable of doing all the operations like a conventional computer. It has other features such as onboard WiFi, GPIO pins, and Bluetooth in order to communicate with external things.

3) How to run Raspberry pi in headless mode?

Raspberry pi in headless mode can be run by using SSH. The latest operating system has an inbuilt VNC server that is installed for taking remote desktop on Raspberry Pi.

4) What are the fundamental components of IoT?

The four fundamental components of an IoT system are:

  • Sensors/Devices: Sensors or devices are a key component that helps you to collect live data from the surrounding environment. All this data may have various levels of complexities. It could be a simple temperature monitoring sensor, or it may be in the form of the video feed.
  • Connectivity: All the collected data is sent to a cloud infrastructure. The sensors should be connected to the cloud using various mediums of communications. These communication mediums include mobile or satellite networks, Bluetooth, WI-FI, WAN, etc.
  • Data Processing: Once that data is collected, and it gets to the cloud, the software product performs processing on the gathered data. This process can be just checking the temperature, reading on devices like AC or heaters. However, it can sometimes also be very complex, like identifying objects, using computer vision on video.
  • User Interface: The information needs to be available to the end-user in some way, which can be achieved by triggering alarms on their phones or sending them notification through email or text message. The user sometimes might need an interface which actively checks their IoT system.

5) What is the difference between IoT and IIoT?

The difference between IoT and IIoT is:

The full form of IoT is the Internet of Things. The full form of IIoT is the Industrial Internet of Things.
A service model is human-centric. A service model is machine-centric.
It supports customer-oriented applications. It supports industry-oriented applications.
Communication transportation is done through wireless devices. Communication transportation is done through both wired and wireless devices.
The quality of data is medium to high. The quality of data is high to very high.
Criticality is not severe. Criticality is severe.

6) List layers of IoT protocol stack

Layers of IoT protocol stack are: 1) Sensing and information, 2) Network connectivity, 3) Information processing layer, 4) Application layer.

7) What are the disadvantages of IoT?

The disadvantages of IoT are:

  • Security: IoT technology creates an ecosystem of connected devices. However, during this process, the system may offer little authentication control despite sufficient cybersecurity measures.
  • Privacy: The use of IoT, exposes a substantial amount of personal data, in extreme detail, without the user's active participation. This creates lots of privacy issues.
  • Flexibility: There is a huge concern regarding the flexibility of an IoT system. It is mainly regarding integrating with another system as there are many diverse systems involved in the process.
  • Complexity: The design of the IoT system is also quite complicated. Moreover, it's deployment and maintenance also not very easy.
  • Compliance: IoT has its own set of rules and regulations. However, because of its complexity, the task of compliance is quite challenging.

8) Define Arduino

Arduino is a free electronics platform having easy to use hardware and software. It has a microcontroller capable of reading input from sensors to control the motors programmatically.

9) List mostly used sensors types in IoT

Mostly used sensor types in IoT are:

  • Smoke sensor
  • Temperature sensors
  • Pressure sensor
  • Motion detection sensors
  • Gas sensor
  • Proximity sensor
  • IR sensors

10) Mention the basic difference between IoT and sensor businesses?

A sensor business does not need an active internet connection to work. Internet of Things requires a control side to work.

11) What are the advantages of IoT?

Key benefits of IoT technology are as follows:

  • Technical Optimization: IoT technology helps a lot in improving techniques and making them better. For example, with IoT, a manufacturer is able to collect data from various car sensors. The manufacturer analyses them to improve its design and make them more efficient.
  • Improved Data Collection: Traditional data collection has its limitations and its design for passive use. IoT facilitates immediate action on data.
  • Reduced Waste: IoT offers real-time information leading to effective decision making & management of resources. For example, if a manufacturer finds an issue in multiple car engines, he can track the manufacturing plan of those engines and solves this issue with the manufacturing belt.
  • Improved Customer Engagement: IoT allows you to improve customer experience by detecting problems and improving the process.

12) What is Bluegiga APX4 protocol?

The Bluegiga APX4 is a solution that supports both the WiFI and BLE platform, and it is based on a 450MHz ARM9 processor.

13) What are the most common IoT applications?

The most common IoT applications are:

  • Smart Thermostats: Helps you to save resources on heating bills by knowing your usage patterns.
  • Connected Cars: IoT helps automobile companies handle billing, parking, insurance, and other related stuff automatically.
  • Activity Trackers: Helps you to capture heart rate patterns, calorie expenditure, activity levels, and skin temperature on your wrist.
  • Smart Outlets: Remotely turn any device on or off. It also allows you to track a device's energy level and get custom notifications directly into your smartphone.
  • Parking Sensors: IoT technology helps users to identify the real-time availability of parking spaces on their phones.
  • Connect Health: The concept of a connected healthcare system facilitates real-time health monitoring and patient care. It helps in improved medical decision-making based on patient data.

14) What is Pulse Width Modulation?

PWM or Pulse Width Modulation is a variation of how much time the signal is high in an analog fashion. The signal can be high or low, and the user can even change the proportion of the time.

15) Mention applications of PWM in IoT

Applications of PWM in IoT are controlling the speed of DC motor, Controlling the direction of a servo moto, Dimming LED, etc.

16) List available wireless communications boards available in Raspberry Pi?

Wireless communications boards available in Raspberry Pi are 1) WiFi and 2) BLE/Bluetooth.

17) What are the functions used to read analog and digital data from a sensor in Arduino?

Functions used to read analog and digital data from a sensor in Arduino are: digitalRead() and digitalWrite().

18) What is Bluetooth Low Energy?

Bluetooth Low Energy is a wireless PAN (Personal Area Network) technology. It uses less power to transmit long-distance over a short distance.

19) Define MicroPython

MicroPython is a Python implementation, which includes a small subset of its standard library. It can be optimized to run on the ModeMCU microcontroller.

20) List available models in Raspberry Pi

Models of Raspberry Pi are:

  • Raspberry Pi 1 Model B
  • Raspberry Pi 1 Model B+
  • Raspberry Pi 1 Model A
  • Raspberry Pi Zero
  • Raspberry Pi 3 Model B
  • Raspberry Pi 1model A+
  • Raspberry Pi Zero W
  • Raspberry Pi 2

21) What are the challenges of IoT?

Important challenges of IoT are:

  • Insufficient testing and updating
  • Concern regarding data security and privacy
  • Software complexity
  • Data volumes and interpretation
  • Integration with AI and automation
  • Devices require a constant power supply which is difficult
  • Interaction and short-range communication

22) Mention some of the commonly used water sensors

The commonly used water sensors are:

  • Turbidity sensor
  • Total organic carbon sensor
  • pH sensor
  • Conductivity sensor

23) Differentiate between Arduino and Raspberry pi

The difference between Arduino and Raspberry pi is:

Arduino Raspberry pi
Arduino is an open, programmable USB microcontroller. It can execute one program at a time.
Raspberry pi is a credit card size computer. Users can run more than one program at a time.

24) What are mostly used IoT protocols?

The mostly used IoT protocols are:

  • XMPP
  • AMQP
  • Very Simple Control Protocol (VSCP)
  • Data Distribution Service (DDS)
  • MQTT protocol
  • WiFi
  • Simple Text Oriented Messaging Protocol(STOMP)
  • Zigbee

25) What are IoT publishers?

IoT Publishers are sensors that send real-time data to intermediate devices or middleware.

26) What is a library in Arduino?

Arduino library is a collection of code that is already written for controlling module or sensor.

27) Mention some of the wearable Arduino boards

Wearable Arduino boards are:

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

28) What is replication?

Replication is the act of syncing data between two or more servers.

29) What is IoT Thingworx?

Thingworx is a platform for the fast development and deployment of connected devices. It is a collection of integrated IoT development tools that support analysis, production, property, and alternative aspects of IoT development.

30) What is Salesforce IoT Cloud?

The Salesforce IoT Cloud is an online platform for storing and processing IoT information.

It is an assortment of various application development elements, which are called lightning.

This program gathers information from websites, devices, customers, and partners. It then triggers actions for period responses.

31) Explain IoT GE-PREDIX

GE or General Electric Predix is a software for the information assortment from industrial instruments. It offers a PaaS which allows users performance management and operation optimization facility. It connects instrumentation, people, and information in an exceedingly conventional technique.

32) List out Some popular companies are working on IoT

Popular companies working on IoT are: 1) Philips, 2) LG, 3) Google, 4) Apple and 5) Samsung.

33) What are various types are of CAN Frame?

Various types of CAN frames are: 1) data frame, 2) request frame, 3) error frame, and 4) overload frame.

34) What is the main difference between floating CPU and fixed-point CPU?

Floating CPU can take floating value directly, whereas fixed CPU is converted to integer format. Thereby, it leads to the loss of some resolution.

35) Define GPIO

GPIO is a programmable pin that can be used to control input or output pins programmatically.

36) Explain Android things

Android things is an Android-based OS that is built for embedded devices.

37) What is the aim of airflow sensors?

The main aim of airflow sensors is to measure the air level in the soil. This sensor enables one to measure it dynamically, from one location, or multiple locations of the garden.

38) Mention suitable databases for IoT

Suitable databases for IoT are:

  • influx DB
  • Apache Cassandra
  • RethinkDB
  • MongoDB
  • Sqlite

39) Why use the scheduler in RTOS?

Scheduler in RTOS is used for switching one task to another.

40) Mention real-time usage of Raspberry pi

  • Home a
  • Portable webserver
  • manipulating the robots
  • Internet radio

41) Define IoT Contiki

IoT Contiki is software that targets explicitly little devices connected with the Internet. It is used with process power bandwidth, power, and restricted memory. Contiki helps for the management of programs, resources, processes, communication, and memory.

42) What is data in IoT?

Data in IoT refers to the information that is collected by the installed devices at any building.

43) List majorly used IoT controllers by industries

Majorly used IoT controllers by industries are: 1) Siemens IoT 2020 and 2) Arduino.

44) What is a crystal oscillator?

A crystal oscillator is the main part of the microprocessor. It executes every single pulse one instruction in CPU.

45) What is the importance of the Internet of Everything?

Internet of Everything is important because:

  • It brings together people, processes, things, and data to make network connections valuable and relevant.
  • It converts the information into actions to create new capabilities and opportunities for businesses.

46) What is WSN?

The full form of WSN is Wireless Sensor Network. It is a network of notes, design to observe and to study physical parameters of the application.

47) What is Zigbee?

Zigbee is the same like Bluetooth. It used in a complex system for low power operation, robustness, and high security.

48) What is Z-Wave?

Z-Wave is an IoT technology that uses low power RF communication. It is designed for home automation products like lamp controllers and sensors.

49) How to install a new library in Arduino?

A new library in Arduino can be installed by selecting the library from the sketch option in Toolbar.

50) What is MQTT?

The full form of MQTT is Message Queue Telemetry Transport Protocol. It is a messaging protocol that is used for tracking devices in IoT.

51) Name some important IoT hardware

IoT hardware includes varieties of devices like router, bridge, sensor, etc.

52) What are the operating systems supported by Pi?

Operating systems supported by Pi are:

  • Raspbian
  • Open ELEC (Open Embedded Linux Entertainment center)
  • Lakka
  • OSMC (Open Source Media Centre)
  • Windows IoT Core

53) How to reduce the size of the sketch?

Reducing the size of the sketch is can be reduced by removing unwanted libraries from the code and make code short and simple.

54) What are the various types of antennas designed for IoT devices?

Various types of antennas designed for IoT devices are:

  • Chip Antenna
  • PCB Antenna
  • Wire Antenna
  • Proprietary Antenna
  • Whip Antenna

55) What is the difference between M2M and IoT?

The difference between M2M and IoT is:

Communication is done within an embedded software at the client site. Communication is done for grand-scale projects.
It uses isolated systems of devices having the same standards. It uses integrated devices, applications, and data across varying standards.
M2M offers limited scalability options. IoT is inherently more scalable.
A cellular network or wired network is used for device connectivity. It uses an active Internet connection for device connectivity.
Machines can communicate with one machine at a time. Many machines can communicate with each other over the Internet.

56) What are the features of influxDB?

Features of influxDB are:

  • Provides support of visualization tools
  • Works with distributed time-series database
  • It does not have any external dependencies

57) How to program Arduino?

Programmers can use the Arduino IDE in order to write an Arduino program. Developers can also use Node.js Johny five-module in order to control Arduino.

58) What are IoT testing tools?

IoT testing tools can be divided into hardware and software:

  • IoT testing software: Tcpdump and Wireshark.
  • Hardware for IoT testing: JTAG Dongle, Digital Storage Oscilloscope, and Software Defined Radio.

59) How to store the high-volume file into Arduino?

A specification called Gridfs can be used for storing high volume file into Arduino.

60) Mention IoT software

IoT software are: 1) Blockchain, 2) windows IoT, 3) Predix, 4) Microsoft Azure, 5) Bluemix, and 6) Node-RED.

61) What is Shodan?

Shodan is an IOT testing tool that can be used to discover which of your devices are connected to the Internet. It allows you to keep track of all the computers which are directly accessible from the Internet.

62) What is a thing in IoT?

IOT thing is an item having an embedded and connected computing device.

63) What is Thermocouple?

A Thermocouple is a device which consists of two different conductors joined together to form an electrical junction.

64) Mention some examples of MEMS sensor

  • MPU6050- Gyroscope
  • ADXL345
  • piezoelectric sensor
  • Accelerometer

65) What are IoT test approaches?

IoT test approaches are: 1) Usability, 2) IoT Security, 3) Connectivity, 4) Performance, 5) Compatibility Testing, 6) Pilot Testing, 7) Regulatory Testing, and 8) Upgrade testing.

66) What is sharding?

Sharding is a method to split data into collections and stored in machines.

67) List hardware prototypes used in IoT

Hardware Prototypes used in IoT are 1) Raspberry Pi, 2) ARM Cortex Family, and 3) Arduino.

68) What is IoT Testing?

IoT testing is a type of testing to check IoT devices. Today there is an increasing need to deliver better and faster services. There is a huge demand to access, create, use, and share data from any device. The thrust is to provide greater insight and control over various interconnected IoT devices. Hence, the IoT testing framework is important.

69) What are the types of IoT?

There are two types of IoT:

  • Internet of Things: It creates a business that uses a gadgets to perform a task.
  • Industrial Internet of Things: It creates business in the industry like agriculture.

70) What is Thingful?

Thingful is a search engine for the Internet of Things. It allows secure interoperability between millions of IoT objects via the Internet. This IOT testing tool also to control how data is used and empowers to take more decisive and valuable decisions.

71) What are interrupts in Arduino?

Interrupts enable specific tasks to process in the background and are enabled by default. Its main job is to ensure the device processor responds fastly to essential events.

72) What is Asset Tracking?

Asset Tracking or Asset management is the process of keeping track of physical assets and information.

73) What are the risks associated with the IOE Internet of Everything?

Risks associated with IOE are 1) Privacy, 2) Security, 3) Network congestion, and 4) Electricity consumption at the peaks.

74) What is the basic difference between the IoT network and Wireless Sensor Network?

Wireless Sensor Network things connected to the wireless network and gather some monitoring environment or data. IoT contains a combination of:

  • WSN
  • Internet
  • Cloud Storage
  • web or mobile application

75) What is the importance of the network in IoT?

The network is the main part of the IoT. It is responsible for providing a practical and smart system that makes strong infrastructure. The network offers scalability to help devices coordinate with other lines with the Internet.

76) What is the connection between IoT and sensors in the commercial enterprise?

Sensors may be used in devices that are not net-connected, while devices need to be connected to the Net with IoT. Yet, sensing is a part of IoT, even if the device is not connected to the Net.

77) Explain the types of testing in IoT?

IoT devises testing types are:

  • Usability Testing: There are so many devices of different shape and form factors are used by the users. Moreover, the perception also varies from one user to others. That's why checking the usability of the system is very important in IoT testing.
  • Compatibility Testing: There are lots of devices that can be connected through the IoT system. These devices have varied software and hardware configuration. Therefore, a possible combination is huge. As a result, checking the compatibility in the IoT system is important.
  • Reliability and Scalability Testing: Reliability and Scalability is important for building an IoT test environment which involves a simulation of sensors by utilizing virtualization tools and technologies.
  • Data Integrity Testing: It's important to check the Data integrity in IoT testing as it requires a large amount of data and its application.
  • Security testing: In the IoT environment, many users are accessing a massive amount of data. Thus, it is important to validate user via authentication, have data privacy controls as part of security testing.
  • Performance Testing: Performance testing is important to create a strategic approach for developing and implementing an IoT testing plan.