Thursday, March 1, 2012

Arduino RN-42 Bluetooth Module

I received this Sparkfun RN-42 Bluetooth Module, which has no level shifter or voltage regulator unlike the Bluetooth Mate Gold which has all the stuff included. All you have to do is hook it up directly to Arduino +5v, TX, and RX, BUT its costs $50 more(basically a circuit board and VERY few components). While, i just looked at the datasheet, used a few resistors(10k and a 20k), some wire and a header; and got the same exact functionality. It requires four connections: TX, RX, VCC(3.3v), and GND; and these were quite easy to solder with a bit of flux on my first try. After connecting it according to the scheme below, just turn on your Arduino(and the RN42), get a serial Bluetooth enabled computer etc, pair them(default password: 1234), and then you can exchange serial data. :)


Front

Back

Connected!

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13 comments:

  1. Blue CreationMay 23, 2012 at 3:57 AM

    Its best feature is that its a serial data exchange Bluetooth Module. Now its easy to get a serial Bluetooth enabled computer.

    ReplyDelete
  2. UnknownNovember 15, 2012 at 3:49 AM

    could you please provide how you connected the rn-42 to the arduino board

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    Replies
    1. JordanNovember 15, 2012 at 4:18 AM

      look at the first image. its not perfect, but it shows you, in red, what the connections are.

      Delete
  3. phprunnerFebruary 2, 2013 at 9:14 PM

    Great tutorial, helped to get me started with my first Arduino project.

    I'm implementing the same setup and hit the wall trying to make Arduino communicate with RN-42. RN-42 itself powers up, pairs with my laptop and echoes everything back when short RX and TX. However when I'm trying to hook it up to Arduino and upload any sketch (even the one that doesn't communicate with serial) Arduino ends up blinking TX led and not finishing the upload.

    Probably I'm not grounding it properly. Any idea how can I troubleshoot this?

    Could you post your Arduino initialization code just in case?

    Thanks a lot!

    ReplyDelete
  4. JordanFebruary 2, 2013 at 9:59 PM

    you need to un-connect the RN42 while uploading ssketches.

    it is no different in any way than using regular serial. the default baud of the RN42 is 9600.

    ReplyDelete
    Replies
    1. JordanFebruary 2, 2013 at 9:59 PM

      at least tx and rx un-connected atleast, i mean.

      Delete
    2. phprunnerFebruary 3, 2013 at 10:33 AM

      Jordan, thanks, it helped. Can send and receive data now!

      Delete
  5. MilindMay 3, 2013 at 1:47 PM

    Hi. i receive the RN-42 Bluetooth Module from Sparkfun. i have try your tutorial for my arduino mega adk. with this setup i'm able to find the RN42 by my android device but application name blue term(andoird app) can not able to connect the device.

    i have add 10k resistors beetween the rx(rn42) and tx(arduino), the 20k resistors add with 10k and gnd to arduino. but still cant connected.

    please help me out.

    ReplyDelete
    Replies
    1. JordanMay 3, 2013 at 9:22 PM

      I'm guessing your entering the password; 1234 ? any exact errors given?

      Delete
    2. MilindMay 4, 2013 at 12:20 PM

      yes i'm entering the password 1234 the device can pair but not connected and dont get any error i just got unable to connect using blue term apk, i have try to use amarino example application, with this application i am able to connect the device but the arduino cant receive the command. please help me out.

      Delete
    3. JordanMay 4, 2013 at 12:48 PM

      hmm. do you have a computer you could test it with?

      Delete
    4. MilindMay 6, 2013 at 12:02 PM

      yes i can debug it.

      Delete
  6. UnknownDecember 31, 2014 at 11:02 PM

    Hi, I need to use RN42 to communicate with Arduino. I need to do a PCB design of the circuit . So is it ok to leave all other pins except those four pins free? Plz help me out.

    ReplyDelete

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