Let's Make Robots!

Bluetooth and Arduino

Calculon320's picture

Happy Holidays LMR,

Calculon is wondering if any of you have used bluetooth with arduino successfully. And if so, what did you use?

He's aware that there's an Arduino BT board, but he's looking to use a standalone module with his Mega to talk to his android phone. Anyone have any experience with this?

Would this work for this purpose?

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rogue's picture

Sparkfun now sells a $40 module, the BlueSmirf Silver.  This is a class 2 module (less range than class 1) but I'm sure thats what you phone is too.  I have a robot that uses an AVR and the same Bluetooth module (different board) to communicate with my smartphone.  Check it out here.  Unfortunately there's no Arduino code there as it uses a straight AVR microcontroller.  However I did include the schematic and all code.

Also, you may look into Python for Android to create Bluetooth applications!

arbarnhart's picture

You may have inferred that my answer is "No" - that device won't do it. It is a slave and you need a master.

RobotFreak's picture

RobotFreak disagree. Depends on your phone. Modern Smartphone can act as master to establisch a connection to a bluetooth slave device. RobotFreak have a similar module and will test it later.

The bad thing with those cheap BT modules is:

  •  These are 3.3V devices. You can't connect it directly to a 5V microcontroller. You will need level shifters for the signal lines and a seperate 3.3V power supply (or the Arduino internal 3.3V PS). 
  • Changing the configuration (Baudrate etc) is only possible from UART (serial) side, not the Bluetooth side. You will need a USB UART module to configure it from a PC, or need to make the configuration from your microcontroller (difficult, you don*'t have a feedback).


rogue's picture

I really like the RN-42/RN-41 used on the Bluesmirf silver/gold from SFE (and also available with breakout from Roving Networks-> RN-42-SM).  You can change the Baudrate and all other commands wirelessly via Bluetooth, frreakin' awesome :-)

FYI the baudrate setting doesn't change until the module is reset (following baudrate configuration).

arbarnhart's picture

I completely forgot about how phones do accessories. Sometimes it even seems more like peer to peer. If you pair one of hose little "hang on your ear" BT headsets you do it from the phone, but my car did the pairing for its BT handsfree with my phone and I only had to use the phone to confirm it was okay.

arbarnhart's picture

I use the BlueTooth Mate. I like it as it mates with an FTDI connection, making it easy to use with the Pro Mini and Fio. I also used it on the breadboard with the Mega. But in all cases, it was just a serial port from the Arduino side. Windows did all the heavylifting to set up the connection. It s far less trivial to be a master. There is a shield that does it that someone posted about recently, but if I remember correctly most of what has been done with it is for cameras.