Common Internet of Things (IoT) Recruitment Questions and Answers for 2023 - IQCode

Understanding IoT (Internet of Things)

The term IoT or Internet of Things was first introduced by Kevin Ashton in 1999. It describes a global network consisting of interconnected physical objects (often referred to as "things") that can collect and share data without any human intervention. These "things" are equipped with embedded systems, such as software, electronics, networks, sensors, etc., and can collect data based on their surrounding environment, transmit it to other devices over the internet, respond to remote commands or even take actions based on the data collected.

Today, IoT devices or "things" include wearables, implants, vehicles, machinery, smartphones, appliances, computing systems, or any other item that can gather and exchange data.

Integration with cloud-based storage and computing, Cyber-Physical Systems, and big data networks can help to create a robust IoT architecture. The objective of the Internet of Things is to extend internet connectivity beyond conventional devices like computers, mobile phones, and tablets, to any device that has the capability to send or receive data.

Here are some IoT interview questions that are typically asked from freshers/entry-level candidates:

1. What are the characteristics of IoT?

Overview of IoT Components

The Internet of Things (IoT) consists of various components that work together to enable connected devices to gather and process data. Some of the main components of IoT include:

  • Sensors and Actuators
  • Connectivity
  • Data Processing and Analytics
  • User Interface and Applications
  • Security and Privacy

Each component plays a crucial role in the functioning of IoT systems, which can be used in various applications such as smart homes, healthcare, transportation, and agriculture.

Advantages of IoT

IoT brings numerous advantages, some of which are:

- Efficiency: IoT allows devices to communicate with each other and automate tasks, leading to increased efficiency and reduced workload.

- Convenience: Smart devices can be controlled remotely through connected devices such as smartphones, providing convenience and ease of use.

- Cost-saving: By automating tasks and improving efficiency, IoT can assist in reducing costs associated with manual labor.

- Personalization: IoT can provide personalized experiences by collecting and analyzing data from connected devices, tailoring environments to individual preferences and needs.

- Improved monitoring: IoT sensors can continuously monitor and measure various metrics, providing real-time information for better decision-making processes.

- Enhanced safety: Wearables and other IoT devices can provide safety and monitoring features, such as alerting for potential health hazards or dangerous situations.

Overall, IoT has numerous advantages that can improve our daily lives and reshape business operations.

Challenges and Risks in IoT

The Internet of Things (IoT) technology is rapidly advancing and has become ubiquitous in many areas of our lives. However, with the benefits come certain challenges and risks. Here are a few:

  • Security: As more devices are connected to the internet, there's an increased risk of cyber attacks. This could mean loss of confidential data, interference with device functionality, and even physical harm.
  • Data privacy: With so many data points being collected, stored, and processed, there's a risk of sensitive personal information being exposed or misused.
  • Interoperability: Different devices and systems may be built on different protocols, which can lead to issues in communication and integration.
  • Scalability: As the number of connected devices expands, it becomes increasingly challenging to manage them all.
  • Regulatory compliance: IoT devices and data collection may be subject to various regulations, and not adhering to them can result in legal and financial consequences.
  • Cost: Implementing and maintaining IoT infrastructure can be expensive, especially for smaller companies or individuals.
  • Ethics: The increasing prevalence of IoT raises ethical concerns, such as the potential for misuse of data and invasion of privacy.

It's important to address these challenges as IoT technology continues to evolve, and ensure that proper measures are taken to mitigate risks where possible.

// Example of measuring temperature with the help of a temperature sensor and sending it to the cloud

Different Types of Sensors in IoT

In the world of IoT, there are many types of sensors that are used to collect and transmit data. Some of the most common types of sensors include:

  • Temperature sensors: used to measure the temperature of the environment or an object.
  • Humidity sensors: used to measure the humidity or moisture content in the air or a substance.
  • Pressure sensors: used to measure the pressure of gases or liquids.
  • Light sensors: used to measure the intensity or amount of light in an environment.
  • Proximity sensors: used to detect the presence of an object within a certain distance.
  • Accelerometers: used to measure changes in velocity or acceleration.
  • Gyroscopes: used to measure angular velocity or rotational motion.
  • GPS sensors: used to track the location of an object or individual.

Each type of sensor has its own unique set of applications and benefits in the IoT ecosystem.

Different Layers of the IoT Protocol Stack and its Classification

The IoT protocol stack is composed of multiple layers that provide specific functionalities to devices. These layers are:

1. Application Layer
2. Network Layer
3. Transport Layer
4. Data Link Layer
5. Physical Layer

The classification of IoT protocols is as follows:

1. Application Protocols
  • HTTP
  • CoAP
  • MQTT
  • XMPP
2. Transport Protocols
  • TCP
  • UDP
  • DCCP
  • SCTP
3. Network Protocols
  • IPv4
  • IPv6
  • RPL
  • 6LoWPAN
4. Data Link Protocols
  • IEEE 802.15.4
  • Bluetooth Low Energy (BLE)
  • ZigBee
  • NFC
5. Physical Layer Protocols
  • Wi-Fi
  • Bluetooth
  • Z-Wave
  • LoRaWAN

Different Communication Models in IoT

IoT (Internet of Things) has various communication models that facilitate the transfer of data between devices. The three main communication models in IoT are:

  1. Device-to-Device (D2D) Communication: This model establishes direct communication between two IoT devices without any intermediate entity. It is mainly used in applications where low-latency communication is required.
  2. Device-to-Cloud (D2C) Communication: This model involves communication between IoT devices and cloud servers. The devices collect data and send it to the cloud for processing and analysis. Examples of D2C communication include smart homes and healthcare monitoring systems.
  3. Device-to-Gateway (D2G) Communication: D2G communication involves IoT devices communicating with an intermediate gateway device that acts as an interface between the devices and the cloud. The gateway device collects and processes data before sending it to the cloud. This model is commonly used in industrial IoT (IIoT) applications.

Each of these communication models serves a specific purpose, and the selection of a model depends on the application requirements, the type of devices being used, and the available resources.

Some of the Most Common IoT Applications

The Internet of Things (IoT) has numerous applications across various industries. Here are some of the most common IoT applications:

  1. Smart Home Devices (e.g. smart thermostats, smart lighting, smart security systems)
  2. Industrial Internet (e.g. predictive maintenance, equipment tracking, supply chain optimization)
  3. Healthcare (e.g. wearables, remote patient monitoring, medication management)
  4. Smart Energy Management (e.g. smart grids, energy consumption monitoring, renewable energy integration)
  5. Transportation (e.g. fleet management, autonomous vehicles, traffic monitoring)

These are just a few examples of the many ways that IoT is being used to improve efficiency, productivity, and convenience in various fields.

How IoT Works

IoT or Internet of Things refers to the connection of everyday devices and objects to the internet, enabling them to send and receive data. The working of IoT involves three main components: sensors/devices, connectivity, and data processing.

Sensors or devices are embedded in objects or systems to collect data like temperature, pressure, or motion. These sensors are connected to the internet or local networks through wired or wireless means, making them accessible from anywhere in the world.

Connectivity refers to the communication network that connects the devices to the internet or local network. The network can be wireless or wired, depending on the device and location. This network makes it possible to access the devices' data and manage them.

The collected data is processed using software tools and analyzed to gain insights into the system's performance or usage metrics. The data can be stored locally or on the cloud, depending on the requirement.

IoT finds its application in various sectors like healthcare, transportation, agriculture, and smart homes. In healthcare, it can be used to monitor patient's vital signs remotely. In transportation, it can be used to optimize fleet management and track cargo. In agriculture, it can be used to monitor soil moisture levels and optimize irrigation. In smart homes, it can be used to automate home appliances' control and security systems.

Overall, IoT enables the exchange of data between various devices and helps in making informed decisions, reducing costs, and improving efficiency.

Explanation of BLE (Bluetooth Low Energy)

BLE stands for Bluetooth Low Energy, which is a wireless communication technology designed for short-range communication. It is a subset of Bluetooth technology that uses less power and requires less processing than traditional Bluetooth. This makes it ideal for use in applications that require low power consumption and small form factors, such as wearable devices, wireless sensors, and smart home appliances. BLE has become popular due to its ability to connect with multiple devices and is now being widely used in the Internet of Things (IoT) industry.

Understanding Thermocouple Sensors

A thermocouple sensor is a type of temperature sensor that operates on the principle of thermoelectric effect. It consists of two wires made of different metals, joined together at one end known as the measuring junction, and connected at the other end known as the reference junction. When the measuring junction is exposed to a temperature change, a voltage is generated across the two wires due to the difference in the Seebeck coefficient of the metals. This voltage is proportional to the temperature change and can be measured and converted into a temperature reading using specialized instrumentation.

Explanation of the term 'Smart City' in IoT

A smart city is a connected city that leverages the Internet of Things (IoT) to improve the quality of life for residents and optimize city operations. IoT sensors, devices and systems are integrated into the city's infrastructure to collect and analyze data, allowing for real-time monitoring and decision-making. This leads to increased efficiency, sustainability and responsiveness to the needs of citizens. Smart cities can use IoT technology to manage traffic flow, reduce energy consumption, monitor air quality, improve public safety and offer a variety of smart services.

Understanding Pulse Width Modulation (PWM)

PWM stands for Pulse Width Modulation, which is a technique used in electronics to control the amount of power delivered to a load. It involves turning a signal on and off at a specific frequency and adjusting the width of the pulse to vary the average power delivered to the load. Essentially, PWM can be used to simulate an analog signal by adjusting the duty cycle of a digital signal. This technique is commonly used to control things like motors, LEDs, and audio signals in electronic devices.

IOT Contiki: Explaining the Basics

Contiki is an open-source operating system designed for resource-constrained Internet of Things (IoT) devices. It allows devices to communicate with each other and with the internet, even with limited memory and processing power. IoT Contiki is a version of Contiki OS specifically tailored for IoT devices. It provides a range of protocols and tools for developing IoT applications. Its lightweight design makes it ideal for small, battery-powered devices that need to be efficient and cost-effective. Overall, IoT Contiki is a popular choice among developers for building IoT systems.

Suitable Databases for IoT

There are several databases that are suitable for IoT applications:

1. MongoDB: This document-based NoSQL database is great for handling unstructured data commonly found in IoT applications. It can also handle large volumes of data and scale as needed.

2. Cassandra: This distributed database system excels at handling high volumes of data and offers great scalability.

3. InfluxDB: This time-series database is designed specifically for handling IoT data that is generated over time. It can efficiently manage data from sensors and other IoT devices.

4. Redis: Often referred to as a "data structure server," Redis excels at handling real-time data streams. It's commonly used to process data from IoT sensors and deliver it to other systems.

5. MySQL: This traditional relational database is commonly used for IoT applications where data needs to be reliably stored and accessed. It's also easy to integrate with other systems.

Sharding Explanation

Sharding is a technique used in database management systems to horizontally partition data across multiple servers. This approach enables high scalability and performance by distributing data and user requests across various servers. By splitting data into different shards, the system can handle a much larger dataset, as well as a higher volume of requests.

In sharding, each server is responsible for servicing a specific subset of data, typically defined by a shard key, which can be a specific attribute or field in the data. Requests that include the shard key are directed to the corresponding server, while requests that do not include it are broadcasted to all servers to ensure all data is captured.

Sharding requires careful planning and management to ensure data consistency and minimize issues such as data loss or network latency. However, when implemented properly, sharding can significantly improve database performance and reliability.

Understanding Replication

Replication refers to the process of creating and maintaining copies of a database or data set. It involves copying data from a primary database to one or more secondary databases. The purpose of replication is to improve data availability, enhance performance and provide redundancy in case the primary database fails. Replication can be done using various techniques such as snapshot replication, transactional replication and merge replication, depending on the specific requirements of the system.

Distinguishing IoT from M2M

As an experienced individual, could you explain the difference between the Internet of Things (IoT) and Machine-to-Machine (M2M) communication?

Understanding IoT Gateway and Its Role in IoT

An IoT gateway is a physical device or software program that serves as a critical intermediate connection point between devices, sensors, and the cloud. Its role is to enhance the security and reliability of IoT networks by connecting devices to the internet and allowing them to communicate with each other.

The IoT gateway also performs various other functions, including:

1. Protocol conversion: It helps in converting data from various sensors and devices so that it can be understood by the cloud.

2. Device management: It enables the management of devices and sensors connected to the network, including their status and configuration.

3. Security: It helps in securing the IoT network and data by acting as a buffer between the cloud and devices.

4. Analytics: It performs data analytics and processing, which is helpful in making real-time decisions and enhancing system performance.

In summary, the IoT gateway is a fundamental component of an IoT network that provides a secure and reliable data exchange between devices and cloud-based services.

Web of Things (WoT) - An Explanation

The Web of Things (WoT) is an extension of the Internet of Things (IoT) that aims to make the devices and services involved in the IoT more easily accessible through a standardized web-based interface. WoT aims to bridge the gap between the physical world of objects and the digital world of the internet by providing a common framework for communicating with devices across different IoT platforms.

In a WoT system, a device or service is represented on the web by a Uniform Resource Identifier (URI), which acts as a unique web address. A WoT-enabled device or service can be accessed and controlled through this web address, using standard web protocols like HTTP and web sockets. This allows developers to create applications that can interact with a wide range of devices and services over the web, regardless of whether they are using the same IoT platform or programming language.

With WoT, developers can build applications that interact with a broad range of devices, such as sensors, actuators, and smart home appliances, using a standardized web-based interface. WoT also allows for the creation of new, interconnected services that can interact with multiple devices and platforms. For example, a WoT-enabled home automation system could integrate with a weather service to adjust heating and cooling based on current weather conditions.

Overall, the Web of Things has the potential to make IoT applications more accessible, interoperable, and scalable, which could unlock new possibilities for innovation and collaboration in the IoT space.

Explanation of MQTT (Message Queue Telemetry Transport Protocol)

MQTT is a machine-to-machine (M2M) communication protocol that is used in Internet of Things (IoT) devices. It is a lightweight protocol that is designed to be efficient and reliable in low-bandwidth and high-latency environments. It works by allowing devices to publish messages to a broker and subscribe to messages from a broker. This publish-subscribe model enables multiple devices to communicate with each other, without the need for a direct connection between them. Overall, MQTT is a popular choice for IoT applications due to its simplicity, speed, and scalability.

Overview of the Bluegiga APX4 Protocol

The Bluegiga APX4 protocol is a wireless communication protocol used for device-to-device communication in IoT (Internet of Things) networks. It operates on the 2.4 GHz frequency band and provides a low-power, low-latency, and secure communication link between devices.

The protocol uses a star topology, where one central device acts as a coordinator and controls the communication between other devices, which are known as nodes. The coordinator device can communicate with up to hundreds of nodes simultaneously.

The APX4 protocol uses a packet-based data transfer mechanism, where data is sent and received in packets. The protocol provides reliable data transfer with error detection and correction mechanisms to ensure data integrity.

In terms of security, the protocol provides AES-128 encryption for secure data transfer, preventing unauthorized access to sensitive data.

Overall, the Bluegiga APX4 protocol is a reliable and secure wireless communication protocol suitable for IoT networks requiring low-power and low-latency communication.

Understanding IoT Device Management and its Importance

IoT device management refers to the administration of IoT devices, including their deployment, configuration, monitoring, and maintenance. It is crucial in ensuring the smooth and efficient operation of large-scale IoT deployments, enabling organizations to manage their vast fleets of devices effectively.

IoT device management provides several benefits, including improved security, better device performance, reduced downtime, and enhanced scalability. It also enables remote device management, facilitating cost-effective operation and troubleshooting of IoT deployments.

Overall, IoT device management is essential in enabling seamless and secure operation of IoT deployments, enhancing their performance and efficiency, and reducing operational costs.

Difference between IoT and IIoT

The Internet of Things (IoT) is the interconnection of all physical devices with the internet or each other to exchange data and share information. It includes consumer devices such as smartphones, smart home devices, wearables, and more.

On the other hand, the Industrial Internet of Things (IIoT) is the use of IoT technologies in industrial applications and processes. IIoT involves connecting machines, sensors, and devices used in manufacturing, energy, agriculture, transportation, and other industries to the internet to collect and analyze data for optimizing and automating industrial processes.

While both IoT and IIoT involve connecting physical devices to the internet, the main difference lies in their applications. IoT focuses on enhancing everyday life and convenience, whereas IIoT is geared towards improving efficiency, safety, and productivity in industrial settings.

//Example of IIoT
const sensorData = require('sensor-data');
const machineLearning = require('machine-learning');

const sensors = sensorData.getSensors('manufacturing');
const data = sensors.readData();

const optimizedData = machineLearning.optimizeData(data);

Meaning of Arduino

Arduino is an open-source electronics platform based on easy-to-use hardware and software. It consists of a series of microcontrollers and a software development environment that simplifies the process of creating electronics projects. The term "Arduino" is often used to refer to the hardware boards themselves, as well as the software that runs on them. The platform is designed to be accessible to people with little or no experience in electronics, programming, or circuit design. It is widely used in educational settings, DIY projects, and professional productions.

Raspberry Pi

Raspberry Pi is a small and affordable computer that was developed by the Raspberry Pi Foundation. It was designed to provide people with an easy and low-cost way to learn coding and computer programming. The Raspberry Pi can be used for a variety of projects, such as media centers, gaming consoles, and home automation systems. It has multiple input/output options and can run a variety of operating systems, including Linux and Windows 10 IoT Core.

What is a Sketch in Arduino and How to Optimize its Size

A sketch in Arduino is a program written in the Arduino Integrated Development Environment (IDE) using C++ programming language. It contains functions, variables, and libraries necessary to control and interact with Arduino boards.

To reduce the size of a sketch, below are some optimization techniques that can be used:

1. Remove unnecessary code: Remove any code that is not being used or redundant. Be cautious not to delete any code that is necessary for the proper functioning of the sketch.

2. Simplify code: Simplify the code as much as possible by removing any unnecessary loops or conditional statements.

3. Use proper data types: Use data types that are appropriate for the particular use case to reduce memory usage.

4. Utilize library functions: Instead of writing code from scratch, use inbuilt library functions. This not only reduces the size of the sketch but also makes the code more efficient.

5. Avoid using Strings: Strings take up a lot of memory and can quickly fill up the limited memory space available on the Arduino board. It is better to use traditional C-style character arrays.

By implementing these techniques, the size of the sketch can be optimized, making it run more efficiently on the Arduino board.

Understanding GPIO (General Purpose Input/Output)

GPIO, or General Purpose Input/Output, is a term used to describe the physical pins found on computers or other devices that can be programmed to either input or output digital signals. These pins can be controlled by software programs to communicate with various peripherals such as sensors, LEDs, or relays. In simpler terms, GPIO pins allow for two-way communication between the physical world and the software world. This makes them an important tool for interfacing with the outside world in electronic projects.

Differences Between Arduino and Raspberry Pi

Arduino and Raspberry Pi are both popular platforms used for electronic projects. However, there are some key differences between the two:

  • Arduino is a microcontroller board used for building simple projects that interact with the physical world, such as controlling lights or motors. Raspberry Pi, on the other hand, is a single-board computer that can be used to run a full operating system and perform more complex tasks such as web browsing and video playback.
  • Arduino has a simpler programming language and is easier for beginners to learn. Raspberry Pi programming requires knowledge of higher-level languages such as Python or Java.
  • Arduino is more suited for tasks that require real-time processing and controlling of physical hardware, while Raspberry Pi is more suitable for tasks that require more computing power and data processing capabilities.
  • Arduino is less expensive and consumes less power than Raspberry Pi.
Overall, the choice between Arduino and Raspberry Pi largely depends on the specific project requirements and the user's level of experience with programming and electronics.

Differences between IoT and Wireless Sensor Networks (WSN)

The Internet of Things (IoT) and Wireless Sensor Networks (WSN) are related technologies that are often used interchangeably. However, there are some key differences between the two:

  • Scope: IoT refers to the network of physical objects that are connected and communicate with each other over the internet. WSN is a type of IoT that is specifically focused on collecting and transmitting sensor data in a specific area.
  • Deployment: IoT can be deployed in a variety of environments, including homes, factories, and smart cities. WSN is typically used in environments where traditional wired networks are impractical, such as in remote or hazardous locations.
  • Range: IoT devices can connect to remote servers over a long range, typically using cellular or satellite networks. WSN devices are designed for short-range communication, often using low-power wireless protocols like Zigbee or Bluetooth.
  • Power: Many IoT devices are powered by batteries, while others are powered by mains electricity. WSN devices are typically battery-powered and designed to operate for extended periods of time without maintenance.
  • Architecture: IoT typically uses a centralized cloud-based architecture, where data is collected and processed in the cloud. WSN often uses a decentralized architecture, where data is collected and processed locally on the sensor nodes before being transmitted to a data sink.

//Example code
public class IoTDevice {
  String name;
  String location;
  String data;

  public void sendToCloud() {
    // Code to send data to cloud server

public class WSNDevice {
  String name;
  String location;
  String data;

  public void transmitToSink() {
    // Code to transmit data to a nearby sink

Explanation of GE-Predix for IoT

GE-Predix is a cloud-based platform developed by General Electric that is specifically designed for Internet of Things (IoT) applications. It provides a comprehensive suite of tools and services that enable companies to build, deploy, and manage industrial applications at scale.

The platform is designed to be developer-friendly, with an open architecture that supports a wide range of programming languages and frameworks. It also provides a set of pre-built components, including data analytics tools, machine learning algorithms, and predictive maintenance capabilities, that can be easily integrated into IoT applications.

One of the key advantages of GE-Predix is its ability to securely connect industrial assets to the cloud. This enables companies to monitor and control their equipment in real-time, giving them greater visibility into their operations and the ability to make more informed decisions. It also allows for the collection and analysis of large volumes of data, which can be used to improve efficiency, reduce downtime, and identify new revenue streams.

Overall, GE-Predix is a powerful platform for companies looking to leverage the benefits of IoT in their operations. Its flexible architecture, robust set of tools and services, and security features make it an ideal choice for large-scale industrial applications.

Some Wearable Arduino Boards

Here are a few examples of wearable Arduino boards:

- LilyPad Arduino
- Adafruit Flora
- Lilypad USB
- Gemma
- TinyLily
- FLORA Wearable Bluefruit LE Module

These boards are specifically designed to be incorporated into wearable projects, with small form factors and low power consumption capabilities. They are great for creating clothing, jewelry, or accessories that can interact with the environment and provide unique functionality.

Explanation of IoT Asset Tracking

IoT (Internet of Things) asset tracking is a system that allows for real-time monitoring and management of assets through the use of connected devices. These devices are embedded with sensors that track the location, movement, and condition of the assets. The data collected is transmitted to a central system where it can be analyzed and used to optimize asset utilization, reduce operational costs, and improve overall performance. This technology has various applications in industries such as logistics, manufacturing, healthcare, and retail, where the ability to track and manage inventory, equipment, and other assets can have a significant impact on productivity and profitability.

Meaning of "Thingful"

"Thingful" is not a commonly used word in the English language. It may be interpreted as a made-up word or a misspelling of the word "thoughtful." Without more context, it is difficult to provide a specific definition for this word.

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