907  Bluetooth Fundamentals and Architecture: Overview

907.1 Introduction

Bluetooth is one of the most ubiquitous wireless technologies in IoT, powering everything from fitness trackers and smart locks to industrial sensors and building automation systems. This chapter series provides a comprehensive guide to Bluetooth technology, covering both Classic Bluetooth and Bluetooth Low Energy (BLE).

TipFor Beginners: What is Bluetooth?

Think of Bluetooth like a wireless conversation between two devices that are close together. Just like how you can talk to a friend standing next to you without needing a phone line, Bluetooth lets devices “talk” to each other without wires.

Simple analogy: Bluetooth is like a short-distance walkie-talkie for your devices. Your phone can “talk” to your headphones, your fitness tracker, or your smart lock—all without any cables!

Two types of Bluetooth:

  • Classic Bluetooth: Like a phone call—good for long conversations (music streaming)
  • BLE (Bluetooth Low Energy): Like text messages—quick updates, then the device goes back to sleep (fitness trackers, sensors)

907.2 Chapter Series Overview

This topic has been split into focused chapters for easier learning. Each chapter builds on the previous one:

907.2.1 Core Chapters

  1. Classic Bluetooth vs BLE
    • Evolution of Bluetooth from 1994 to present
    • Key differences between Classic and BLE
    • Power consumption and battery life calculations
    • When to choose each technology
  2. Bluetooth Topologies
    • Star, broadcast, and mesh network configurations
    • BLE advertising modes for beacons
    • Bluetooth Mesh for building-scale deployments
    • Power optimization for different topologies
  3. Bluetooth Piconet Architecture
    • Central/peripheral (master/slave) roles
    • The 7-device active limit in Classic Bluetooth
    • Scatternet formation for extended networks
    • Workarounds for connection limits
  4. Bluetooth Connection Establishment
    • Classic Bluetooth discovery (inquiry and paging)
    • BLE advertising and scanning
    • Connection parameters (interval, latency, timeout)
    • Bonding and pairing methods
  5. Bluetooth Protocol Stack
    • Classic vs BLE protocol layers
    • GATT architecture (services, characteristics, descriptors)
    • Notification vs indication for data delivery
    • Adaptive Frequency Hopping (AFH)
  6. Bluetooth Profiles
    • Serial Port Profile (SPP) for wireless UART
    • Human Interface Device (HID) for input devices
    • Advanced Audio Distribution Profile (A2DP)
    • Choosing the right profile for your application

907.2.2 Hands-On Learning

  1. Bluetooth Hands-On Lab
    • Build a BLE sensor beacon using Wokwi simulator
    • Implement GATT services and characteristics
    • Handle connections and send notifications
    • No hardware required—browser-based simulation

907.3 Quick Reference

907.3.1 Classic Bluetooth vs BLE at a Glance

Aspect Classic Bluetooth BLE
Purpose Audio streaming, file transfer Sensors, beacons, wearables
Power Medium (mA range) Very low (uA range)
Battery Life Days to weeks Months to years
Data Rate 1-3 Mbps 125 kbps - 2 Mbps
Connection Persistent Can be transient
Profiles A2DP, HFP, SPP GATT services

907.3.2 When to Use Bluetooth

Choose Bluetooth when:

  • Smartphone connectivity is required (BLE built into all phones)
  • Short-range communication (10-100m) is sufficient
  • Battery life is important (BLE)
  • Audio streaming is needed (Classic A2DP)

Consider alternatives when:

  • Internet connectivity required (use Wi-Fi)
  • Large mesh network needed (consider Zigbee, Thread)
  • Very long range required (use LoRa, cellular)

907.4 Learning Path

907.4.1 Beginner Path (2-3 hours)

  1. Read Classic Bluetooth vs BLE for foundational understanding
  2. Skim Bluetooth Topologies for network concepts
  3. Complete Bluetooth Hands-On Lab for practical experience

907.4.2 Intermediate Path (4-6 hours)

  1. Complete beginner path
  2. Study Piconet Architecture for deeper understanding
  3. Learn Connection Establishment for optimization
  4. Explore Protocol Stack for GATT development

907.4.3 Advanced Path (8+ hours)

  1. Complete intermediate path
  2. Master Bluetooth Profiles for application development
  3. Review case studies and worked examples in each chapter
  4. Implement challenge exercises in the hands-on lab

907.5 Key Takeaways

  • BLE is not backward compatible with Classic Bluetooth—they are separate protocols
  • Power optimization requires understanding advertising intervals, connection parameters, and sleep modes
  • GATT is the foundation of BLE data exchange—services contain characteristics with properties
  • Bluetooth Mesh extends BLE to building-scale with managed flooding
  • Profile selection depends on your use case (audio, sensors, input devices)

907.6 What’s Next

Start with Classic Bluetooth vs BLE to understand the fundamental differences between the two Bluetooth technologies and when to use each in your IoT projects.

For hands-on learners, jump directly to the Bluetooth Hands-On Lab to build a working BLE sensor beacon in your browser.

Deep Dives:

Comparisons:

Hubs: