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SparkFun Bluetooth Modem - BlueSMiRF Gold

We rebooted this amazing product. See our new BlueSMiRF v2.

The BlueSMiRF is the latest Bluetooth****wireless serial cable replacement from SparkFun Electronics! These modems work as a serial (RX/TX) pipe. Any serial stream from 2400 to 115200bps can be passed seamlessly from your computer to your target. We've tested these units successfully over open air at 350ft (106m)! The latest version of this board also breaks out PIO4.

Note: The remote unit can be powered from 3.3V up to 6V for easy battery attachment. All signal pins on the remote unit are 3V-6V tolerant. No level shifting is required. Do not attach this device directly to a serial port. You will need an RS232 to TTL converter circuit if you need to attach this to a computer.

Note: This is a single unit only. We recommend the purchase a USB dongle to interface to a computer if you do not already have access to a computer with Bluetooth connectivity.

****Radio Modem * Extremely small radio - 0.15x0.6x1.9" * Very robust link both in integrity and transmission distance (100m) - no more buffer overruns! * Low power consumption : 25mA avg * Hardy frequency hopping scheme - operates in harsh RF environments like WiFi, 802.11g, and Zigbee * Encrypted connection * Frequency: 2.402~2.480 GHz * Operating Voltage: 3.3V-6V * Serial communications: 2400-115200bps * Operating Temperature: -40 ~ +70C * Built-in antenna

  • v6.15 Firmware
  • FCC Approved Class 1 Bluetooth
  • 42x16.5x5.6mm

SparkFun Bluetooth Modem - BlueSMiRF Gold Product Help and Resources

Using the BlueSMiRF

September 16, 2013

How to get started using the BlueSMiRF and Bluetooth Mate Silvers.

SparkFun Arduino ProtoShield Hookup Guide

May 17, 2018

The SparkFun Arduino ProtoShield PCB and ProtoShield kit lets you customize your own Arduino shield using whatever custom circuit you can come up with! This tutorial will go over its features, hardware assembly, and how to use the shield with an Arduino R3 footprint.


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Does any one know what the right number for "RS232 to TTL converter circuit " so I could connect the Bluetooth to my pc? There are plenty of them in Sparkfun website but I have not idea which one fits.

  • Member #838098 / about 8 years ago / 1

    Does anyone know how to do a factory reset of the BlueSMiRF Gold ?

    The data sheet isn't clear about this. I tried setting the pin PIO4 to HIGH multiple times but it didn't worked.

  • Member #895736 / about 7 years ago * / 0

    -snip- nevermind, I read over the page again and got my answer

  • Member #660058 / about 9 years ago * / 2

    A great small unit that works well with the Arduino UNO. I personally have found it is much easier to connect and talk to than other similar Bluetooth devices.

    I had some issues where removing power from the device meant that it no longer communicated on power up. After a few false starts (command mode, and factory reset using: 'SF,1') to re-establish connection I found that I had to enter command mode, set the bluetooth to the lower baud rate ('SU,96' ; i.e. 9600) to the device, exit the command mode (---) and then run my default bluetooth code. It wasn't enough to just have the baud rate change in my code. Now I can power down and up without communication issues.

  • DaG / about 9 years ago / 1

    Has anyone had success connecting it to an Arduino Due or Parallax Propeller? I've setup the bluetooth with my laptop, COM ports make sense, and when I open the Propeller Serial Terminal and select the COM port the light goes green solid, indicating there is a connection, but after that nothing appears, I've tried it using the example programs made by GadgetGangster here: http://www.gadgetgangster.com/news/56-jeffs-shop/534-bluetooth-howto.html

    Hooked up an oscilloscope, nothing seems to be registering from the TX pin of the bluetooth module... plenty of activity in the RX pin though.... not sure what to make of it.

    • DaG / about 9 years ago / 1

      As for Arduino, it appears Due is the only board in existence that cannot use Software Serial due to a different architecture, just my luck.... Does anyone know anything about how to hook up bluetooth on a Due?

      • M-Short / about 9 years ago / 1

        For help with Software Serial on a Due try emailing techsupport@sparkfun.com. But don't forget the Due has 4 hardware serial lines which should be enough for most applications (if you need more check out the FreeSoC)

  • Member #38182 / about 9 years ago / 1

    Is there a command to reset the module to the same state as I received it from Sparkfun?

  • Member #38182 / about 9 years ago / 1

    I see a reference to AT command set, but I cannot find any documentation with actual "AT' commands. I see other commands when using the $$$ sequence. What's up?

  • Member #38182 / about 9 years ago * / 1

    Weird Problem. I am using a wireless RS-232 replacement at 115,200 baud. Works great, no issues, but if I send an ASCII "2" the connection breaks down. Have to re-start, re-boot, re-connect, whatever. Is this a design feature on purpose? I used the SF,1 factory default and the issue is not there now. ??

  • Member #621607 / about 9 years ago / 1

    I have a BlueSIMiRF rigged up to an Arduino BlueSMiRF pins rigged as follows viewed from the top: Empty Arduino pin 3 Arduino pin 2 Arduino ground Arduino 5v Empty

    I'm using the Arduino code from the Sparkfun instructions.

    The device is not entering command mode and instead is sitting in start-up mode with out timing out.

    Any ideas?

    • Which Arduino are you connecting to? Formatting of your post makes it difficult to tell if the pins are hooked up correctly, so that would be the first thing I would double check.

  • Member #38182 / about 10 years ago / 1

    A quick power supply question. I am adding this to an embedded design that is powered by 3.3V. This Blue SMiRF Gold board states that it will work at 3.3V but the SMiRF board schematic has a 3.3V LDO regulator on board. Correct me but a 3.3V source voltage may not be able to power this device since it would require a higher voltage than 3.3V to drive the on board LDO. What am I missing here? Trying to release a board layout now and need some advice or help, thanks.

  • Member #618656 / about 10 years ago / 1

    Hi, BLE bee is compatible with XBee arduino and support wireless programming. View and download codes from: http://www.elecfreaks.com/store/products_new.html

  • Member #527686 / about 10 years ago / 1

    Do all four ground pins on the RN-41 have to be connected to ground like is done in the schematic, or is there common ground within the RN-41 so only one needs to be connected to ground? (Pins 1, 12, 28, 29)

  • Member #519563 / about 10 years ago / 1

    Guys I so sorry, I was very afraid, by not to find nothing, really sorry. You Know when is unknown something, by any word more easy that is, it's complicated understand.

  • Member #519563 / about 10 years ago / 1

    Hello guys, can you help me??, so I have a modem BlueSMIRF GOLD and an ARDUINO UNO CARD, I need to change the Name, the Password, and Baud.- How I can connect physically both devices for to do this?. Can I do this with AT commands througth an arduino sketch?

    • Check out this tutorial.

      If that doesn't help contact tech support (techsupport@sparkfun.com). Also, try not to spam the comments section with multiple questions.

  • Member #103262 / about 10 years ago / 1

    Hello all; I am experiencing an interesting issue...I am not able to figure out whether this due to my code or a hardware problem. I was hoping to gauge you all to see if anyone has experienced this. Although the documentation states that such a state is NOT possible, I have experienced it. I have purchased over 20 of these for a project and I have experienced this with 3 of them (although I have not tested each one extensively).

    ISSUE: The module is connected (green led - solid) and then all of a sudden I get the following: BOTH the RED led (fast blink) and GREEN (solid) led are lit up at the same time. This suggests the module is both in command mode and connected at the same time. The documentation states such a state is not possible.

    Suggestions? Thanks.

  • Member #499181 / about 10 years ago / 1

    Can this BT connect to uart/serial port APM 2.5 3drobotics?

    • I couldn't find a pinout for 2.5, but my guess is that you likely can interface them.

      • Member #519563 / about 10 years ago / 1

        ello guys, can you help me??, so I have a modem BlueSMIRF GOLD and an ARDUINO UNO CARD, I need to change the Name, the Password, and Baud.- How I can connect physically both devices for to do this?. Can I do this with AT commands througth an arduino sketch?

        • We have examples on how to change these things on this tutorial. If you want to use this with an Arduino, you would simply send these commands over a serial connection between the Arduino and the BlueSMIRF.

  • jcholton / about 11 years ago / 1

    Could this be used to connect to an iPhone or Android device using an application?

  • Member #140531 / about 11 years ago / 1

    curious about that 10K series resistor to the RX pin in lieu of level shifting. is there an internal resistor that's forming a divider? the way it seems, a 5V microcontroller would fry that pin after a while... can't find any documentation on this in the datasheet.

  • jcholton / about 11 years ago / 1

    Is it possible to attach an antenna to this such as the 2.4GHz Antenna - Adhesive (U.FL connector) from sparkfun?

    • not without a bit of effort. there is no place to put the antenna, but you theoretically COULD take off the chip antenna and rig something up.

Customer Reviews

4 out of 5

Based on 10 ratings:

Currently viewing all customer reviews.

1 of 1 found this helpful:

Great and easy to work with

The module interfaced easily and was very simple to get working. My only problem is that occasionally the module will freeze. I cannot tell if the module's buffer is filling or if it is receiving a certain string to go into a command mode; either way it freezes until reset now and then. I would use this for prototyping but more research would be needed before I would consider depending on this for anything critical.

1 of 1 found this helpful:

Wonderful Serial Tunnel

This module was purchased to replace a RF system that was giving us trouble in the prototype phase. Once I got this unit wired up it was easy to use and wonderfully simple. The hardest part was finding an android app that would do what I wanted it to do. Changing the settings is really easy once you have a Bluetooth terminal running. I was able to do all of the settings adjustment on the fly with my phone! It has been a blessing to work with. I plan on figuring out how to get this module into many of my future projects.

1 of 1 found this helpful:


I wanted to implement a point-to-multipoint piconet. Since a document I found on the Sparkfun website talked about that very thing, I assumed the bluesmirf would support it. I was disappointed to learn that it doesn't. I tried a serial point-to-point scheme, but it takes several seconds to connect, and that's too slow for my application.

1 of 1 found this helpful:

Susceptible to interference

Tried this module as a Bluetooth interface to a serial port. Configured the module to 57600 baud (which is the port speed on my device) and had multiple instances of either corruption or choking on the speed. I was hoping to use this module to gain a bit more distance with its more power, but even at 3 feet it just could not handle the data flow. If you are using it for audio or something where static is OK, then this is for you. For applications where you need the data to reliably get from point A to point B, then not so good. I think they are trying to pack too much into the module? I don't know. Roving Networks doesn't exist any more, so there is no support either. I guess MicroChip bought them out and kind of abandoned the product line. We used to be able to talk directly to the tech guys at Roving in the old days.

I found that the cheap BT modules from China are far superior for the simple BT-to-SPP applications even though they don't have the most powerful radios in them.

It's very strange, I was just expecting more for 7X the price of the China modules.

Did not work as expected

I purchased this modem to use in conjunction with the SparkFun Arduino ProtoShield v2. My expectation was that I can use this modem to eliminate the USB cable that connects the Arduino to my laptop. It does not do that. I followed a lot of troubleshooting advice and I can only prove that it functions. This means my laptop bluetooth can find it and they can exchange basic info. However, I can't program my Arduino or use the Arduino serial terminal over that bluetooth connection from my laptop to the BlueSMiRF board. It is advertised as "wireless serial cable replacement ". I wish it was.


SMiRF surveillance has never been easier with this module.

Range performance

I had several Arduino projects where I used AT-09 modules. These had a range of about 30 feet going through two walls. I purchased BlueSMiRF modems for the increased range. These modems did not perform any better than the AT-09 modules using the same environmental conditions.

Easiest way to talk to your Arduino / microcontroller over Bluetooth

Solder on some pin headers, connect this baby to your Arduino's UART, and you're ready to talk to a mobile device or laptop. Works like a charm with PyBluez, too!

Just what I needed

Extremely easy to interface to and get running. Sparkfun's quick shipping gave me the edge I needed to get my project started quickly.

Reliable performance; hassle to program

Once I figured out how to program the name and baud rate the BlueSMiRf works great... very reliable and solid connection each time. Programming the module is not straightforward. You have to follow the Hookup guide closely and hold your mouth just right while lifting your left leg to put the module into command mode. Great module otherwise. I will buy more.