JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech IV INTERNET OF THINGS Previous Question Paper (February/March - 2022 - R18)

The physical design of an IoT system refers to the physical nodes and devices that form the network and provide the functionality for sensing, actuation, data processing, and communication. It consists of two main components: IoT Devices and IoT Communication Blocks.

IoT Devices are the building blocks that provide the ability to sense, actuate, and monitor the environment. These include:

• Sensors: Devices that detect changes in the physical environment and convert them into electrical signals (e.g., temperature, humidity, or motion sensors).
• Actuators: Devices that perform actions based on the signals received from the controller (e.g., motors, relays, or lights).
• Microcontrollers/Processors: The core units, such as Arduino, Raspberry Pi, or ESP8266, that process the data collected from sensors and execute control logic.

IoT Communication Blocks manage the connectivity between devices and the internet or cloud infrastructure. This layer includes:

• Communication Modules: Hardware interfaces that facilitate data transmission, such as Wi-Fi, Bluetooth, ZigBee, LoRa, or cellular modules (GSM/LTE).
• Communication Protocols: Standardized sets of rules that define how data is exchanged, such as MQTT, CoAP, HTTP, or AMQP, ensuring interoperability between heterogeneous devices.

A Wireless Sensor Network (WSN) is a spatially distributed network of autonomous sensors used to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, or pollutants. WSNs are fundamental to IoT as they enable the collection of real-time data from remote or inaccessible locations.

Key characteristics and components of WSNs include:

• Sensor Nodes: Small, low-power devices equipped with a sensing unit, a processing unit, a transceiver for wireless communication, and a power source (typically a battery).
• Topology: Nodes are often deployed in an ad-hoc manner and communicate wirelessly. They typically use multi-hop communication where data is forwarded from node to node until it reaches a central gateway or sink node.
• Gateway/Sink Node: A more powerful node that collects data from all sensor nodes in the network and bridges the WSN to the external internet or a central server for further processing.
• Energy Constraints: Since sensor nodes are often battery-powered and deployed in large numbers, energy efficiency is a critical design requirement. Protocols are designed to minimize power consumption by utilizing sleep cycles and efficient routing algorithms.
• Applications: WSNs are extensively used in precision agriculture, industrial monitoring, structural health monitoring, and environmental surveillance.