Top IoT Interview Questions and Answers 2025

IoT is generally described to be a network of interconnected physical devices or objects embedded with sensors, software, and connectivity to collect and exchange data over the Internet. 

An Internet of Things system consists of four key components: 

a) Sensors/Devices: These are physical objects or devices with embedded sensors to collect data. 

b) Connectivity: It enables devices to connect and communicate with each other. 

c) Data processing: It involves processing and analysing the collected data. 

d) User interface (UI): It allows users to interact with the system and control devices. 

Sensor networks in IoT are formed by a collection of interconnected sensors that collaborate to gather data from the surrounding environment. These sensors communicate with each other to transmit the collected data to a central processing unit for further analysis and decision-making. 

MQTT (Message Queuing Telemetry Transport) is a lightweight messaging protocol commonly used in IoT applications. It is designed for efficient communication and data transfer between devices with limited resources and unreliable network connections. 

The Internet of Things ensures data security and privacy through various measures, including: 

a) Encryption: Data transmitted between devices is encrypted to prevent unauthorised access. 

b) Authentication: Devices are authenticated to ensure that only trusted devices can access the system. 

c) Access control: Access to data and devices is restricted based on user privileges. 

d) Regular updates: Devices and systems are kept up to date with the latest security patches. 

Edge computing refers to performing data processing and analysis at the edge of the network, which is closer to the data source. It helps reduce latency and bandwidth usage by processing data locally. On the other hand, cloud computing involves storing and processing data in remote cloud servers, providing scalability, centralised management, and access to advanced analytics. 

HTTP (Hypertext Transfer Protocol) and MQTT (Message Queuing Telemetry Transport) are both communication protocols. HTTP is widely used for web-based applications, while MQTT is specifically designed for efficient machine-to-machine communication in resource-constrained environments. 

IPv6 (Internet Protocol version 6) provides a larger address space compared to IPv4, which is essential for accommodating the vast number of Internet of Things devices. With IPv6, each device can have a unique IP address, enabling seamless connectivity and communication in the IoT ecosystem. 

Zigbee and Z-Wave are wireless communication protocols used for home automation. Zigbee operates on the 2.4 GHz frequency band and has a larger network range, while Z-Wave operates on the sub-GHz frequency band, offering better penetration through walls and objects. Additionally, Zigbee supports a larger number of devices in a network compared to Z-Wave. 

In the Internet of Things, big data refers to the large volumes of data generated by connected devices. Big data analytics techniques are applied to extract valuable insights, patterns, and trends from this data. It helps in making data-driven decisions, improving operational efficiency, and enabling predictive maintenance. 

There are several popular tools and techniques for Internet of Things data visualisation, including: 

a) Dashboards: Interactive graphical interfaces that display real-time data and insights. 

b) Charts and graphs: Visual representations of data using various chart types. 

c) Heatmaps: Visual representations of data density or intensity on a geographic map. 

d) Geospatial visualisation: Visualising data on maps to analyse spatial patterns and relationships. 

Predictive maintenance in the Internet of Things involves using data from sensors and devices to predict when maintenance or repairs are required. By analysing the collected data and applying machine learning algorithms, potential failures or issues can be identified in advance, enabling proactive maintenance actions and reducing downtime. 

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Internet of Things platforms provide a framework and set of tools to develop, deploy, and manage IoT applications and devices. They offer functionalities such as data management, device connectivity, security, analytics, and integration with other systems. These platforms simplify the development process and enable scalability and interoperability. 

In the client-server architecture, the devices or sensors act as clients – while the central server manages and controls the devices. The clients collect and send data to the server, which processes and stores the data. The server can then send commands or instructions back to the clients based on the analysis of the data. 

A Implementing IoT in industrial environments poses challenges such as: 

a) Interoperability: Ensuring seamless integration of diverse devices, protocols, and systems. 

b) Security: Protecting sensitive industrial data from cyber threats and unauthorised access. 

c) Scalability: Managing a large number of connected devices and handling massive data volumes. 

d) Legacy systems: Integrating IoT with existing legacy systems and infrastructure. 

e) Reliability: Ensuring continuous operation and reliability of devices in harsh industrial conditions.