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Bluetooth Modules — HC-05, HC-06, BLE 4.0 and NRF Wireless Modules for Arduino
Quick Answer
A Bluetooth module is a compact wireless communication board that enables microcontrollers such as Arduino, ESP32, and Raspberry Pi to send and receive data wirelessly over the 2.4GHz band using Bluetooth Classic 2.0 or Bluetooth Low Energy BLE 4.0 protocols.
KitsGuru stocks 18 Bluetooth and NRF wireless modules, including HC-05, HC-06, HM-10 BLE 4.0, NRF51822, and Bluetooth audio boards, priced from Rs 113 to Rs 1,099. Classic UART modules such as HC-05 and HC-06 operate at 3.3V–5V with around 10m range, while BLE modules such as HM-10 and NRF51822 draw under 15mA, making them suitable for battery-powered IoT devices, wearables, and beacons.
Key Takeaways
- KitsGuru stocks 18 Bluetooth and NRF wireless modules, including HC-05, HC-06, HM-10 BLE 4.0, NRF51822, and MH-M18 audio boards.
- HC-05 supports Master and Slave mode, while HC-06 is Slave-only.
- BLE 4.0 modules like HM-10 and NRF51822 draw around 8–15mA, making them better for low-power projects.
- Classic Bluetooth modules like HC-05 and HC-06 draw around 30–40mA and are suitable for Arduino UART serial communication.
- All UART Bluetooth modules connect through TX/RX pins; a voltage divider is recommended on the RX pin when using 5V Arduino boards.
What Is a Bluetooth Module?
A Bluetooth module is a compact printed circuit board containing a Bluetooth radio transceiver, antenna, and supporting components that allows microcontrollers to communicate wirelessly. The module handles the Bluetooth protocol stack internally and provides a simple UART serial interface to the host microcontroller, so no low-level radio programming is required.
KitsGuru's Bluetooth and NRF module collection covers three main wireless categories: Classic Bluetooth UART modules for direct serial communication, Bluetooth Low Energy 4.0 modules for power-sensitive IoT applications, and Bluetooth audio receiver boards for wireless audio streaming. These modules are useful for Arduino projects, ESP32 systems, Raspberry Pi interfaces, robotics, IoT devices, wireless controls, beacons, and DIY speaker projects.
Types of Bluetooth Modules — Classic vs BLE vs Audio
Choose the correct Bluetooth module based on your application’s data rate, power budget, range requirement, and device compatibility.
| Type | Modules | Voltage | Current | Range | Best For |
|---|---|---|---|---|---|
| Classic BT 2.0 | HC-05, HC-06 | 3.3V, 5V tolerant | 30–40mA | 10m | Arduino UART serial communication and smartphone app control |
| BLE 4.0 | HM-10, NRF51822 | 3.3V | 8–15mA | 15–50m | IoT sensors, wearables, beacons, and low-power devices |
| BT Audio 4.2 | MH-M18, MH-M28 | 5V | 10–20mA | 10m | Wireless audio streaming and DIY speaker projects |
Bluetooth Module Comparison — HC-05 vs HC-06 vs HM-10 vs NRF51822
Use this comparison table to select the right Bluetooth or NRF wireless module for your project.
| Module | BT Type | Voltage | Current | Range | Master / Slave | Best For |
|---|---|---|---|---|---|---|
| HC-05 | Classic 2.0 | 3.3V, 5V tolerant | 30–40mA | 10m | Both | Arduino peer-to-peer communication and AT command configuration |
| HC-06 | Classic 2.0 | 3.3V, 5V tolerant | 30–40mA | 10m | Slave | Smartphone app control and simple serial link projects |
| HM-10 | BLE 4.0 | 3.3V | 8–15mA | 15–20m | Both | IoT devices, iOS BLE apps, and low-power builds |
| NRF51822 | BLE 4.0 | 3.3V | 10–12mA | 30–50m | Both | Beacons, wearables, and long-range BLE projects |
| MH-M18 | BT Audio 4.2 | 5V | 10–20mA | 10m | Slave | Wireless audio receiver and DIY speaker builds |
How to Choose the Right Bluetooth Module
The right Bluetooth module depends on the device you want to connect, the power source, the communication mode, and the required wireless range.
1. Choose by Device Compatibility
For Android phones, Windows laptops, and general Arduino serial communication, use HC-05 or HC-06 Classic Bluetooth modules. For iPhone, iPad, and modern low-power mobile applications, use HM-10 or NRF51822 BLE 4.0 modules, because iOS applications generally require BLE unless the device is MFi certified.
2. Choose by Power Budget
For battery-powered projects such as sensor nodes, wearables, and beacons, choose a BLE module such as HM-10 or NRF51822. These modules draw around 8–15mA, compared to around 30–40mA for Classic Bluetooth modules like HC-05 and HC-06.
3. Choose by Communication Mode
If your project needs one Arduino to initiate a connection to another Bluetooth device, use HC-05 because it supports both Master and Slave mode. If your project only needs to receive connections from a phone app, HC-06 is sufficient and easier to configure.
4. Choose by Range Requirement
For standard room-scale wireless communication, HC-05 and HC-06 provide around 10m line-of-sight range. For longer BLE range, use HM-10 or NRF51822, which can support approximately 15–50m range depending on environment and antenna design.
Which Microcontrollers Are These Modules Compatible With?
Most UART Bluetooth modules are compatible with any microcontroller that has a hardware or software serial UART interface.
- Arduino: Compatible with Arduino Uno, Nano, Mega, and Leonardo through TX/RX pins. Use a voltage divider on the RX pin for 3.3V module protection.
- ESP32: External Bluetooth modules can be connected through UART2 pins such as GPIO16 and GPIO17, although ESP32 already includes built-in Bluetooth and BLE.
- Raspberry Pi: Connect using GPIO14 TX and GPIO15 RX with PySerial or similar serial communication tools. Raspberry Pi uses 3.3V logic.
- STM32 Blue Pill: UART-capable STM32 boards can connect through USART peripherals with 3.3V logic compatibility.
Why Buy Bluetooth Modules from KitsGuru?
- Wide range of Bluetooth and NRF modules including Classic Bluetooth, BLE 4.0, and audio variants.
- Suitable for Arduino, ESP32, Raspberry Pi, robotics, IoT, STEM, and DIY electronics projects.
- Options available for serial communication, low-power wireless sensing, and wireless audio streaming.
- GST-compliant invoices available for Indian customers.
- Ships from Lucknow, India with next working day dispatch.
Frequently Asked Questions About Bluetooth Modules
What is the difference between HC-05 and HC-06 Bluetooth modules?
HC-05 supports both Master and Slave mode, allowing it to initiate connections to other Bluetooth devices. HC-06 works only in Slave mode and accepts incoming connections. HC-05 is preferred for Arduino-to-Arduino communication, while HC-06 is suitable for smartphone app control.
What is Bluetooth Low Energy BLE and when should I use it?
Bluetooth Low Energy or BLE is designed for devices that transmit small amounts of data and need low power consumption. BLE modules like HM-10 and NRF51822 are suitable for wearables, IoT sensors, health monitors, and beacon applications.
Can I use these Bluetooth modules with Arduino and ESP32?
Yes. UART Bluetooth modules such as HC-05, HC-06, and HM-10 connect to Arduino TX/RX pins using SoftwareSerial or hardware serial. ESP32 can also use external modules through UART pins such as GPIO16 and GPIO17.
What is the range of HC-05 and NRF51822 Bluetooth modules?
HC-05 usually provides around 10 metres line-of-sight range. NRF51822 BLE modules can achieve around 30–50 metres line-of-sight range depending on the environment, power design, and antenna layout.
What voltage do HC-05 and HC-06 Bluetooth modules operate at?
HC-05 and HC-06 modules generally include an onboard 3.3V regulator for VCC connection with 5V Arduino systems. However, their TX/RX logic works at 3.3V, so a voltage divider is recommended on the RX pin when using 5V logic.
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