RN42-I/RM Bluetooth V2.1 Module
RN42-I/RM Bluetooth V2.1 Module
RN42-I/RM Bluetooth V2.1 Module
The RN42-I/RM is a compact Bluetooth V2.1 wireless module engineered for embedded systems requiring low-power, Class 2 wireless connectivity with integrated antenna technology. Professional electronics engineers and IoT developers utilize this module to add wireless capabilities to microcontroller-based projects, industrial automation systems, and consumer electronics without requiring extensive RF expertise. This module solves the critical challenge of implementing reliable Bluetooth communication in space-constrained applications while maintaining power efficiency and maintaining backward compatibility with legacy Bluetooth devices.
Product Overview
The RN42-I/RM operates on the Bluetooth V2.1 specification with Enhanced Data Rate (EDR) support, delivering data rates up to 3 Mbps for faster wireless communication. The module features an integrated PCB antenna and operates in the 2.4 GHz ISM band with Class 2 range capability (approximately 10-100 meters depending on environment and antenna orientation). Built on a proven chipset architecture, the RN42-I/RM provides stable SPP (Serial Port Profile) and HFP (Hands-Free Profile) support, making it ideal for serial communication replacement applications where traditional wired connections are impractical.
This module incorporates advanced power management features including sniff mode for reduced current consumption during idle periods, making it suitable for battery-powered applications. The RN42-I/RM includes firmware that supports both master and slave modes, allowing flexible network topology configurations. The compact form factor (approximately 13x23mm) and standard pin configuration enable straightforward integration into existing PCB designs with minimal external component requirements, typically requiring only decoupling capacitors and antenna matching components for optimal performance.
Key Specifications
| Specification | Details |
| Product Type | Bluetooth V2.1 Wireless Module with EDR |
| Brand | Microchip Technology |
| Origin | Original/Authentic |
| Warranty | 7 days on manufacturing defects |
| Shipping | 1-5 days from Bengaluru |
| Delivery | 7-8 days across India |
| Support | 24/7 via Email and WhatsApp |
| Bluetooth Version | V2.1 with Enhanced Data Rate (EDR) |
| Data Rate | Up to 3 Mbps with EDR, 1 Mbps basic rate |
| Operating Frequency | 2.4 GHz ISM Band (2402-2480 MHz) |
| Transmission Power | Class 2 (4 dBm typical) |
| Range | 10-100 meters depending on environment |
| Operating Voltage | 3.3V DC |
| Current Consumption | Active: 30-50mA, Sniff Mode: 1-5mA |
| Module Dimensions | Approximately 13mm x 23mm |
| Antenna Type | Integrated PCB Antenna |
| Supported Profiles | SPP, HFP, A2DP, AVRCP |
| Operating Temperature | -10 to +60 degrees Celsius |
Key Features
- Bluetooth V2.1 with Enhanced Data Rate delivering 3 Mbps throughput for faster wireless data transmission compared to basic rate implementations
- Integrated PCB antenna eliminating the need for external antenna components and reducing module footprint in compact embedded designs
- Dual-mode operation supporting both master and slave configurations for flexible network topologies in point-to-point and piconet applications
- Advanced power management with sniff mode reducing current consumption to 1-5mA during idle periods, extending battery life in portable applications
- Standard UART interface (TTL/CMOS compatible) enabling straightforward integration with microcontrollers without additional level-shifting components
- Multiple Bluetooth profile support including SPP for serial communication, HFP for hands-free audio, and A2DP for stereo audio streaming
- Class 2 transmission power providing reliable 10-100 meter range suitable for indoor and short-range outdoor wireless applications
- 3.3V single supply operation with minimal external component requirements reducing BOM cost and PCB complexity
Applications and Use Cases
- Wireless Serial Communication: Replace RS-232/RS-485 connections in industrial equipment, data loggers, and test instruments using SPP profile for transparent serial data transfer
- Portable Medical Devices: Integrate into pulse oximeters, glucose monitors, and fitness trackers requiring low-power wireless connectivity to smartphones and tablets
- Automotive Aftermarket Systems: Implement in OBD-II diagnostic adapters, hands-free calling modules, and vehicle telematics systems for Android and iOS integration
- IoT Sensor Networks: Deploy in wireless sensor nodes for environmental monitoring, building automation, and industrial IoT applications with battery backup requirements
- Consumer Electronics: Add Bluetooth capability to gaming controllers, smart home devices, and audio equipment requiring backward compatibility with legacy Bluetooth devices
- Robotics and Hobby Projects: Enable wireless control of Arduino-based robots, drone systems, and remote-controlled vehicles through smartphone applications
How to Use
The RN42-I/RM module connects to your microcontroller via UART interface using four primary connections: VCC (3.3V), GND, RX (receive), and TX (transmit). Ensure proper decoupling with a 10uF capacitor across VCC and GND placed as close as possible to the module pins to prevent power supply noise. The module requires 3.3V supply; if your microcontroller operates at 5V, implement voltage dividers on the RX line (using 10k and 20k resistors) to protect the module input while the TX output is typically 3.3V compatible with 5V logic inputs.
Configure the module using AT commands through the UART interface before deployment. Key commands include AT+BTNAME to set the Bluetooth device name, AT+BTPIN to configure the pairing PIN, and AT+BTMODE to select master or slave operation. After pairing with a host device, the module operates in transparent serial mode where data sent to the UART is transmitted wirelessly and vice versa. For optimal performance, position the module away from metal enclosures and high-frequency noise sources, and test range in your specific environment as obstacles and interference affect actual wireless range.
Frequently Asked Questions
What is the difference between RN42-I/RM and other Bluetooth modules like HC-05?
The RN42-I/RM features Bluetooth V2.1 with EDR support providing 3 Mbps data rate compared to HC-05's 1 Mbps basic rate. RN42 includes advanced power management with sniff mode for better battery efficiency and supports multiple profiles including A2DP for audio streaming. However, HC-05 offers simpler AT command sets and lower cost, making it suitable for basic serial communication while RN42 is preferred for applications requiring higher throughput and audio capability.
Can I use the RN42-I/RM with 5V microcontrollers directly?
The RN42-I/RM operates on 3.3V and its input pins are not 5V tolerant. You must implement voltage division on the RX line using a 10k and 20k resistor divider to reduce 5V signals to approximately 3.3V. The TX output from the module is 3.3V which is typically recognized as logic high by 5V microcontrollers. Always verify your specific microcontroller's input voltage specifications before connecting.
How do I pair the RN42-I/RM with a smartphone?
Put the module in pairing mode using the AT+BTD command or by holding the pairing button if available on your development board. The module will appear in your smartphone's Bluetooth device list with the name you configured using AT+BTNAME. Select it from the available devices list and enter the PIN code (default is usually 1234 or as configured with AT+BTPIN). Once paired, the module will automatically reconnect when powered on if within range.
What is sniff mode and how do I enable it?
Sniff mode is a low-power Bluetooth feature that reduces current consumption to 1-5mA by periodically checking for incoming data instead of continuously listening. This significantly extends battery life in portable applications. Enable sniff mode using AT+SNIFF command with parameters specifying sniff intervals. The module automatically enters sniff mode after a configurable idle period, reducing power consumption without disconnecting from the paired device.
When will I receive my order?
Orders are dispatched within 1-5 business days from our Bengaluru warehouse. Delivery takes 7-8 days to most locations across India.
What is your return and warranty policy?
We offer a 7-day return policy on manufacturing defects only. Contact support within 7 days of receipt for free replacement or full refund. Not applicable for user damage or misuse.
Are bulk discounts available?
Yes, wholesale pricing for orders of 10 or more units. Contact our sales team via WhatsApp or email for a customized bulk quote.
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- Returns: 7-day return policy on manufacturing defects only
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