notes-shivam

5. Wireless sensor networks

2 min read

Sensor Networks / Wireless Sensor Networks (WSNs)

Introduction

  1. A Sensor Network is a collection of spatially distributed sensor devices that monitor and record physical or environmental conditions.
  2. A Wireless Sensor Network (WSN) is a type of sensor network where sensors communicate wirelessly.
  3. Common applications include environmental monitoring, healthcare, military surveillance, and smart cities.

Architecture

  1. Sensor Nodes: Small devices with sensing, processing, and communication components.
  2. Sink/Base Station: Collects data from sensor nodes and forwards it to the user or central system.
  3. Communication Links: Wireless connections (typically short-range, low-power).
  4. User Interface: Final destination where collected data is processed and used.

Components of a Sensor Node

  1. Sensing Unit: Detects physical conditions like temperature, light, motion.
  2. Processing Unit: Handles data processing and control (usually a microcontroller).
  3. Communication Module: Enables wireless data transmission (e.g., ZigBee, Bluetooth, RF).
  4. Power Supply: Usually a battery; energy efficiency is critical.
  5. Optional Components: GPS, actuators, or memory depending on use-case.

Features of WSNs

  1. Low Power Consumption: Nodes are often battery-powered.
  2. Self-Organization: Nodes can configure themselves into a network.
  3. Scalability: Can scale from a few to thousands of nodes.
  4. Redundancy and Fault Tolerance: Multiple nodes can sense the same area.
  5. Data Aggregation: Reduces redundant data to save energy and bandwidth.

Communication Protocols

  1. ZigBee (IEEE 802.15.4): Common in WSNs for low-power, short-range communication.
  2. Bluetooth Low Energy (BLE): Used in some small-scale sensor networks.
  3. Wi-Fi / Cellular: Used when long-range or high data rate is required.
  4. Proprietary RF protocols: Customized for specific applications.

Types of Sensor Networks

  1. Static WSNs: Nodes are fixed in place (e.g., agriculture monitoring).
  2. Mobile WSNs: Nodes can move (e.g., wearable health monitors).
  3. Underground WSNs: Nodes are placed below the surface (e.g., soil monitoring).
  4. Underwater WSNs: Used for ocean and lake monitoring.
  5. Multimedia WSNs: Use sensors like cameras and microphones.

Challenges in WSNs

  1. Limited Energy Resources
  2. Scalability and Deployment in Harsh Environments
  3. Data Security and Privacy
  4. Reliable and Efficient Communication
  5. Sensor Fault Tolerance and Maintenance

Applications

  1. Environmental Monitoring: Forest fire detection, pollution tracking
  2. Agriculture: Soil moisture, weather condition monitoring
  3. Health: Patient vital sign tracking (e.g., wearable sensors)
  4. Military: Battlefield surveillance, enemy detection
  5. Industrial Monitoring: Equipment health and performance
  6. Smart Homes and Cities: Energy management, traffic control

Summary & Keywords

  • WSN: Wireless Sensor Network
  • Components: Sensor, Microcontroller, RF module, Battery
  • Protocols: ZigBee, BLE, Wi-Fi
  • Features: Low power, scalable, self-organizing
  • Applications: Healthcare, Environment, Agriculture, Military
  • Challenges: Energy, Security, Scalability

Graph View

Backlinks