Top 30+ IoT Interview Questions and Answers (2024)

The following are the main features and characteristics of IoT:

• Connectivity: 

This is the most critical aspect of IoT. The IoT components, i.e. sensors, compute engines, data hubs, etc., can only operate appropriately with seamless communication among the interrelated members. You can connect to IoT devices in multiple ways, including radio waves, Bluetooth, WiFi, and Li-Fi.

• Analysing/Sensing: 

Once all the relevant things are connected, the next step is to analyse the collected data and use it to build practical business intelligence. For example, a sensor generates data but will only be helpful if appropriately interpreted. It is essential to extract knowledge from the generated data.

• Active Engagements: 

Through IoT, multiple products, cross-platform technologies, and services work together on an operational engagement basis. 

• Scalability: 

Every day, more and more elements connect to the IoT zone. Therefore, IoT setups should be able to handle massive expansion. The data generated as a result is immense, and it should be handled correctly.

IoT devices usually consist of four main components:

• Sensors: 

A sensor is essential for gathering live data from the surroundings; however, the nature of this data can vary. Sensors allow IoT devices to connect to the real world and the environment. This could be as simple as your phone having a temperature sensor, GPS, an accelerometer, or as complex as a live video feature on a social media platform.

• Connectivity: 

All data is sent to a cloud upon collection, which is done by connecting the sensors to the cloud through various communication mediums. Various IoT devices use different types of connectivity.

• Data Processing: 

Once the data is collected and reaches the cloud, the processors process it. Data processing software can enhance IoT devices in various ways, for example, from adjusting the air conditioner's temperature to recognising faces on mobile phones.

• User Interface: 

An IoT device interacts with a user through a User Interface. A user interface is an IoT system's visible, tangible component that users access and involves presenting the information to the end user. A well-designed user interface simplifies the user experience and encourages them to interact more. 

There are several benefits of IoT technology, including:

• Improved user engagement: 

IoT facilitates a better user experience by automating tasks. In a car, for example, any issue will be detected automatically by sensors. It will be notified to both the driver and manufacturer.

• Technical optimisation: 

IoT has improved technology and made it more efficient. It has turned old devices into smarter ones by allowing them to transmit data over the Internet, facilitating communication with people and other IoT-enabled devices—for example, coffee machines, intelligent toys, innovative microwaves, etc.

• Ease of Access: 

IoT enables real-time information from almost any location. All you need is a smart device connected to the Internet.

• Improved Insights: 

IoT provides real-time insights that lead to more efficient resource management.

• New business opportunities: 

By collecting and analysing data from the network, you can uncover new business insights and generate new opportunities while reducing operational costs.

• Effective Time Management: 

The Internet of Things saves time. While we commute to work, we can read the latest news on our phones, browse a blog about our favourite hobbies, or shop online.

• Improved security measures: 

Using IoT, access control systems can provide additional security to organisations and individuals. For example, IoT technology in surveillance can assist in improving an organisation's security standards and identify any suspicious activity.

Some of the drawbacks of IoT are:

• Security: 

IoT technology is an interconnection of connected devices. However, despite sufficient cybersecurity measures, the system may need more authentication control during this process.

• Privacy: 

IoT exposes actual personal data without the user's active participation. This creates lots of privacy issues.

• Flexibility: 

There is considerable concern regarding the flexibility of an IoT system. It is mainly regarding integrating with another system, as many diverse systems are involved in the process.

• Complexity:

Designing the IoT system is quite complicated. Additionally, its deployment and maintenance are also challenging.

• Compliance: 

Since IoT has its own set of rules and regulations because of its complexity, compliance is challenging.

IoT is used to make intelligent devices to use in our everyday lives. These devices are embedded in IoT technology to manifest a more significant quantum of automation than before. IoT can create a more fantastic network enabling different devices to interact with each other, thereby making our daily lives better and more straightforward.

For example, IoT-enabled sensor-driven home appliances automatically turn off when not in use or through virtual assistants. It can regulate most devices, from the lights to television, air conditioning, and many more.

IoT is not limited to our gadgets only. Even our smartwatches, sunglasses, earphones, and many more have evolved through IoT. Additionally, industries like transportation, infrastructure, educational institutes etc., are all affected by IoT.

IoT protocols protect data and ensure it is exchanged securely between devices via the Internet. Additionally, these protocols define how data is transmitted over the Internet, ensuring that the data exchanged between connected IoT devices is secure.

Different communication layers and their IoT protocols are-

The most common IoT applications are:

• Smart Thermostats: 

Knowing your usage patterns helps save resources on heating bills.

• Activity Trackers: 

This helps to capture heart rate patterns, calorie expenditure, activity levels, and skin temperature on your wrist.

• Smart Outlets: 

You can remotely turn on or off any device. It also lets you track a device's energy level and get custom notifications directly to your phone.

• Parking Sensors: 

IoT technology helps users to identify the availability of parking spaces on their phones.

• Connected Health: 

The concept facilitates real-time health monitoring and patient care. It helps in improved medical decision-making based on patient data.

The mainly 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

Many industries can benefit from IoT, such as:

• healthcare,
• agriculture,
• manufacturing,
• automotive,
• public transportation,
• environment,
• smart cities,
• smart homes,
• consumer devices, etc.

The Raspberry Pi is a small credit card-sized, low-cost computer plugged into a computer monitor or TV. It uses a standard keyboard and mouse and performs all the operations like a typical computer. Additionally, it also has onboard Wi-Fi, GPIO pins, and Bluetooth to communicate with external electronic devices.

Sensors are the most critical components used in IoT devices because they are the input devices that detect changes in the environmental condition and act accordingly. Sensors detect specific conditions such as heat, light, sound, distance, pressure, etc., and then generate an electrical signal after measuring their magnitude. 

Recently, IoT sensors have evolved significantly to enhance productivity, low cost, and improve safety.

The most commonly used sensors in IoT-

• IR sensors

• Pressure sensors

• Gas sensors

• Temperature sensors

• Proximity sensors

• Motion detection sensors

• Smoke Sensors

The primary differences between IoT and IIoT are as follows:

The databases that are suitable for IoT and can store data of IoT applications include:

• Influx DB

• MongoDB

• Apache Cassandra

• RethinkDB

• SQLite

IoT contains multiple components like sensors, cloud components, data processing software, cutting-edge user interfaces, etc. It uses Raspberry Pi with a quad-core processor as an Internet gateway for IoT devices. Here, sensors connect the devices to the cloud.

Raspberry Pi controls outputs with GIPO (general purpose input/output) pins. It collects data using sensors. When the cloud receives the data, the software processes it and decides what action to perform without user intervention.

A user interface is required to check if user input is needed or if they want to check in on the system. The user's adjustments are then sent to the cloud and from the cloud back to the sensors or devices to make changes. As a result, it thoroughly creates a highly reactive and intuitive device which increases the automation of the device.

Arduino is a platform that offers easy-to-use hardware and software to create electronic projects. It has a microcontroller and software to write and upload code to the physical board. Arduino boards read inputs like a light on a sensor and turn them into an output like activating a motor.

Some features of Arduino are: 

• Cross-platform – The Arduino IDE is designed to run on different operating systems, like Windows, macOS, and Linux.

• Open source and extensible software and hardware.

• Easy to use for beginners.

• Inexpensive compared to other microcontroller platforms.

IoT devices need to be updated on a timely basis once installed. Occasionally, it must be replaced or repaired, resulting in downtime. The problem can be solved using IoT Device management to keep the devices in good shape. 

IoT device management involves provisioning, authenticating, configuring, monitoring, and maintaining connected devices and software. Effective device management ensures IoT devices' health, security, and connectivity.  

To manage IoT devices, you need to meet the following four requirements. 

• Provisioning and Authentication: 

IoT devices can be attacked easily since their network can be accessed via the Internet. This problem is solved by provisioning and authenticating the devices. 

By provisioning, you modify the device's off-the-shelf settings to those needed to work with your network. To prevent intrusions and safeguard proprietary information, authentication ensures that only authorized devices are enrolled.

• Configuration and Control: 

It is always necessary to configure a new device before you begin using it. It is also critical to control and configure devices after deployment to ensure certain aspects such as performance, security, and functionality. 

• Monitoring and Diagnostics: 

The device may perform poorly due to software bugs or other issues. To diagnose these issues, users must constantly monitor their devices. Device management assists in analysing these issues to resolve them quickly, and efficiently.

• Updates and Maintenance: 

For a device to function flawlessly, it must be updated after it is installed. Good device management hinges on the ability to update and maintain the software of remote devices securely.

Asset tracking means 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. 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 continuously or periodically, 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.

The different types of frames in CAN are:

• Data frame

• Remote frame

• Error frame

• Overload frame

Pulse Width Modulation (PWM) is a modulation technique used in communication systems. It produces variable-width pulses that signify the amplitude of an analog input signal. It helps in encoding the amplitude of a signal into a pulse width/duration of another signal for transmission.

In IoT, PWM is mainly used to control the DC motor's speed, the direction of a servo motor, dim the LED, etc.

A thermocouple sensor measures temperature by coupling two metal pieces together. The temperature is measured at a junction between these two pieces of metal joined at one end. Metal conductors generate a small voltage, which can be interpreted to calculate the temperature. 

A thermocouple is a simple, robust, cost-effective temperature sensor in multiple types and sizes. Additionally, they measure a wide temperature range, making them suitable for various applications, such as scientific research, industrial settings, home appliances, etc. 

WoT is an advancement of the Internet of Things by integrating the Internet, i.e.network and Web Architecture, i.e. applications. In short, the Web of Things (WoT) aims to facilitate IoT's interoperability and usability. It is a web standard for communication between intelligent devices and web applications.

The Bluegiga APx4 is a low-power wireless System-on-Module (SOM). It's an ideal development platform for gateways since it has integrated Wi-Fi, Bluetooth 4.0, ARM, and Linux. 

Wireless and Bluetooth low energy (BLE) can be used together without interference as they comply with coexistence protocols. Bluegiga Apx4 supports Wi-Fi and Bluetooth, and its 450 mhz Arm9 processor provides smooth performance.

The different types of antennas used for IoT devices are-

• Wire Antenna

• PCB Antenna

• Chip Antenna

• Whip Antenna

• Proprietary Antenna

The differences between Arduino and Raspberry Pi are:

Shodan stands for Sentient Hyper-Optimized Data Access Network. It is an IoT search engine that maps and provides information about internet-connected devices/systems. In other words, Shodan is an IoT tool used to identify Internet-connected devices and keep track of all the machines with direct Internet access.

IoT devices with low memory, power, bandwidth, and computing power were explicitly targeted during the development of the Contiki operating system. Despite its basic design and simplicity, it has many standard capabilities in today's operating systems. It is possible to manage things like programmes, processes, resources, memory, and communication with its assistance. 

Furthermore, its low weight and flexibility have contributed to its popularity, making it the operating system of choice for many professionals, researchers, and academics.

Sharding splits extensive databases into smaller, faster, 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 to store it more efficiently. Sharding is necessary for a dataset that cannot be stored in a single database.

IoT gateways enable communication between devices, sensors, equipment, and systems. It is a central hub for all IoT devices and connects them to the cloud, converting communication among them and analysing data to create valuable information. 

Several critical functions are performed by an IoT gateway, including translating protocols, encrypting, processing, managing, and filtering data. As part of an IoT ecosystem, gateways sit between devices and sensors to communicate with the cloud.  

IoT gateways are commonly used for:

• Interconnecting devices

• Connecting devices to the cloud

• Transforming IoT communications

• Data filtering

• Reducing security risks etc.

The different available models of Raspberry Pi used in IoT are-

• Raspberry Pi 1 Model A

• Raspberry Pi 1 Model A+

• Raspberry Pi 1 Model B

• Raspberry Pi 1 Model B+

• Raspberry Pi Zero

• Raspberry Pi 3 Model B

• Raspberry Pi Zero W

• Raspberry Pi 2

MicroPython is a Python implementation that includes a small subset of its standard library, which can be optimised for running on the ModeMCU microcontroller.

Replication is the act of syncing data between two or more servers. During replication, the data on many servers are synced; this mechanism simultaneously stores comparable data on many websites or servers. Because of this functionality, data may be retrieved smoothly even when the server is experiencing an outage or significant demand. 

Users can maintain constant access to the data without interfering with or slowing down the experience of other users. A server considered the source of the data is called a publisher, and a server considered the location where the data is duplicated is called a subscriber.