The RN-42 Bluetooth Module provides a reliable method for creating a wireless serial communication interface between two devices such as a microcontroller, PC, cell phone, or another module. This module can pair up with devices supporting Bluetooth SPP (Serial Port Profile) to establish a serial interface. The RN-42 Bluetooth Module is breadboard-friendly and is compatible with all 5V and 3.3V microcontroller platforms.
The RN-42 Bluetooth Module communicates using asynchronous serial and supporting RTS/CTS flow control. If you do not wish to use hardware flow control or your device does not support it, you may tie the RTS and CTS lines together on the module.
The command set used by the RN-42 Class 2 Bluetooth device is similar to the industry standard Hayes AT protocol.
There are four pairs of configuration jumpers on this board. One is for easy selection of 9600 baud or a software-selectable baud rate (1200 to 921K; default 115.2K). One sets the device as a Bluetooth Master. One is used for Auto Discovery (acts differently depending on setting of the Master jumper; see user manual). One is used to restore the device to factory settings (must be set on power-up then toggled three times, so you can't accidentally reset the unit).
A 3-pin jumper is used to set the module for use with 3.3V or 5V systems.
The module has three LEDs. The green LED blinks at various rates to provide an indication of system status. The blue LED illuminates when a Bluetooth connection has been established. The red LED indicates data being sent over the UART when the module is in its remote configuration mode.
RN-42 Bluetooth Module Features
- Fully qualified Bluetooth 2.1/2.0/1.2/1.1 module
- Low power consumption for long-lasting battery-powered projects
- Range typically between 35 and 50 feet line-of-sight indoors
- Auto-connect/discovery/pairing modes make connecting to other modules easy
- Compatible with 5V and 3.3V microcontrollers
- LEDs provide visual indication of connection/mode status
- 9600 default baud rate
- Remove jumper for 115K baud rate or custom baud rate set in software (1200 to 921K)
- 2×7 male header with 0.1" spacing (extra row provides more stable connection to your hardware)
- Power requirements: 5.0V DC or 3.3V DC @ ~5mA sleep; ~15mA idle; ~20mA transmit; ~50mA max
- Communication interface: 5V/3.3V asynchronous serial interface with RTS/CTS flow control, from 1200 bps to 921K bps
- Operating temperature: -40 to +185 °F (-40 to +85 °C)
- Dimensions: 2.33 × 1.16 × 0.45 inches (59.18 × 29.46 × 11.43 mm)
|Pin ||Name ||Function |
|1||GND||Digital Ground |
|2||VIN||5V or 3.3V power input (must be regulated) |
|3||RST||Resets the device when brought to GND (0V) |
|4||RX||Receive data input to RN-42 UART |
|5||TX||Transmit data output from RN-42 UART |
|6||RTS||Ready To Send output from RN-42 UART |
|7||CTS||Clear To Send input from RN-42 UART |
Bluetooth Transceiver Module Resources
Remember to order two of these boards unless one of your devices already has a Bluetooth modem!