August 9, 2025 0 In New posts

HC-05 vs. Ai-Thinker PB-03: Which Bluetooth Module Should You Choose?

HC-05

Content:

 

Bluetooth connectivity is essential for wireless projects, but choosing between the HC-05 (Classic Bluetooth) and Ai-Thinker PB-03 (Bluetooth 5.1 LE) can be tricky. This guide compares their features, power efficiency, range, and best use cases to help you pick the right module.

 Overview: HC-05 vs. PB-03

Feature HC-05 (Classic Bluetooth) Ai-Thinker PB-03 (BLE 5.1)
Bluetooth Version Bluetooth 2.1 + EDR (Classic) Bluetooth 5.1 Low Energy (BLE)
Data Speed ~2.1 Mbps (SPP profile) ~2 Mbps (optimized for bursts)
Range 10–20m (Class 2) Up to 100m (with antenna)
Power Consumption ~30mA (active), no deep sleep ~8mA (active), 0.4μA (sleep)
Interface UART (5V/3.3V compatible) UART/USB (3.3V)
Security Basic PIN code pairing AES encryption, secure BLE

 

Key Differences Explained

A. Bluetooth Technology

  • HC-05:

    • Uses Classic Bluetooth (2.1+EDR) for continuous data streaming (e.g., audio, serial communication).

    • Best for high-throughput applications like wireless speakers.

  • PB-03:

    • Uses Bluetooth Low Energy (BLE 5.1) for battery-efficient, intermittent data (e.g., sensors, wearables).

    • Supports long-range mode (4× coverage with coded PHY).

Winner:

  • HC-05 for audio/continuous data.

  • PB-03 for IoT/battery-powered projects.

B. Power Efficiency

  • HC-05:

    • No sleep mode – constantly draws ~30mA, draining batteries quickly.

  • PB-03:

    • Ultra-low-power sleep mode (0.4μA) – ideal for coin-cell-powered devices.

Winner: PB-03 for long-term battery life.

C. Range & Connectivity

  • HC-05:

    • Limited to 10–20m (standard Class 2 range).

  • PB-03:

    • Up to 100m with external antenna (BLE long-range mode).

Winner: PB-03 for outdoor/remote sensors.

D. Ease of Use

  • HC-05:

    • Plug-and-play with any SPP-compatible app (e.g., Bluetooth Terminal).

    • Works with Arduino, Raspberry Pi via simple AT commands.

  • PB-03:

    • Requires BLE-compatible apps (e.g., nRF Connect).

    • More complex setup for advanced features (beacon mode, mesh).

Winner: HC-05 for beginners.

 Best Use Cases

✔ Choose HC-05 If You Need:

  • Wireless audio (DIY speakers, car kits).

  • Serial communication (Arduino-to-PC/Android).

  • Legacy device support (older phones, industrial systems).

✔ Choose PB-03 If You Need:

  • Battery-powered IoT (sensors, wearables).

  • Long-range BLE (smart agriculture, asset tracking).

  • Secure data transmission (medical/financial devices).

Which One Should You Buy?

Project Type Best Module Why?
Audio streaming HC-05 Classic Bluetooth supports SPP.
Battery IoT sensors PB-03 Ultra-low power + BLE 5.1 range.
Arduino beginners HC-05 Easier UART setup.
Secure BLE projects PB-03 AES encryption, long-range mode.

wiring diagram

HC-05 Bluetooth Module Wiring

Components Needed:

  • HC-05 Module

  • Arduino/ESP32

  • 3.3V or 5V Power (check module version)

  • Voltage Divider (if using 5V Arduino)

Connection Diagram:

  • HC-05 → Arduino/ESP32
  • VCC → 5V (or 3.3V for 3.3V modules)
  • GND → GND
  • TXD → RX (Pin 0 on Arduino)
  • RXD → TX (Pin 1 on Arduino)
  • STATE → Optional (status LED)
  • EN/KEY → Optional (for AT mode, connect to 3.3V via button)

Ai-Thinker PB-03 BLE Module Wiring

Components Needed:

  • PB-03 Module

  • Arduino/ESP32 (3.3V logic only!)

  • USB-to-TTL converter (for debugging)

Connection Diagram:

  • PB-03 → Arduino/ESP32
  • 3.3V → 3.3V (do not use 5V!)
  • GND → GND
  • TXD → RX (Pin 0 on Arduino)
  • RXD → TX (Pin 1 on Arduino)
  • P0/P1 → Optional GPIOs (for buttons/LEDs)

 

Troubleshooting Tips

 

  1. HC-05 Not Responding?

    • Ensure voltage divider is used if connecting to 5V Arduino.

    • Try AT+ORGL to reset factory settings.

  2. PB-03 Not Pairing?

    • Confirm 3.3V power and check baud rate.

    • Use nRF Connect App to debug BLE connections.

 

External Resources

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