Bluetooth Sends Data, Won't receive commands from laptop

Projects Networking, Protocols, and Devices
1

Hi All-

I have a cheap bluetooth from Amazon: RS232
http://www.amazon.com/gp/product/B00B1P1RGO/ref=oh_details_o08_s00_i00?ie=UTF8&psc=1

I have the dongle set up and drivers installed. I have no problem pairing with the device on Windows 7. But I can't get TeraTerm or my PortMon or other programs to monitor the device because it says it is already in use and it can't open.

The bluetooth dongle for some reason creates two different COM ports, both for incoming signals.

Anyway. Everything I have looked up (arduino BT pages, youtube videos, blogs, etc.) makes it look simple and I can't quite find a thread or solution to this problem. Anyone know what is up? Care to educate me a little bit? I feel like I might be missing something little.

Also- I have the RX on the BT connected to TX on Arduino Nano and vice versa.

Any help from the community would be greatly appreciated!

Thanks!

2

I don't know anything about the Nano, or how it communicates, but the most common mistake with Uno etc. is to try using bluetooth with the USB cable still connected. I don't know if the two COM ports is an indication of that.

Here is some background that you might find useful.

http://homepages.ihug.com.au/~npyner/Arduino/GUIDE_2BT.pdf
http://homepages.ihug.com.au/~npyner/Arduino/BT2way.ino

3

Hi Thank you for your reply.
I did a ton of experimenting last night with the bluetooth and my programs and I am almost there but still missing something.

I loaded my sketch via USB cable. It all checked out over the port monitor.

I uplug the cable and hook up my bluetooth. The transmit channel on the bluetooth to the computer is working. The commands are sent from the arduino and they show up on the computers end. But... I can not send a command from the computer to the arduino. I don't know if it is a bluetooth receive issue or something else. Any ideas here?

**To Summarize: ** The bluetooth will send the signal to the computer but the computer is not able to send a signal to the bluetooth/arduino (i.e. like in one of the simple echo programs that are used for BT testing). This is true using the arduino port monitor or other programs.

And, does anyone know how to change the baud rate of the BT on Mac Mavericks?

Thank you for any help!

4

jfarrant05:
Mac

You clearly said Windows 7 before, but now I see the above has crept into the conversation and may be the cause of your problems.
In short: your To Summarize: is insufficiently clear, particularly as you do seem to be doing all the right things, including I understand, proving up the programme with the serial monitor.

5

Thanks to you again for looking. Let me see if I can explain myself:

My bluetooth problems with the COM ports and whatnot seemed to get all goofed up with the inclusion of that bluetooth dongle on the Windows machine. It creates extra ports, and they are all busy, and I can't bring any program to connect with them (arduino port monitor says already in use, teraterm says can't connect. )

So I first verified the sketch:
If I load the sketch with Windows 7, when using the USB cable, I receive and send through arduino port monitor (either on my Windows or on Mac) with no problems (since it is monitoring the port created by the cable).

Then I unplug and connect the bluetooth and plug into alternate power for a wireless setup.

I am unable to establish connection with the Windows machine for whatever reason the dongle doesn't like me, but with my Macbook, the bluetooth will connect and communicate (but only one way). The arduino port monitor can see the messages being sent to it, but I can't send a message to it. For instance, if I run the program you mentioned before that does an echo of the user input, it does not respond to user input. But still prints out "Go on, type something..."

The mac has the .tty and .cu options for ports...which I dont understand yet, (probably the same reason Windows creates two ports also with its dongle), I suppose the answer could lie in there somewhere.

I am kind of lost as to what to try / test next. I was just wondering if this situation stood out to anyone.

So close yet so far. I hope this clears it up a little bit.

About that last note:
When I change the sketch baud rate to be different than 9600. The messages that are printed are coming out as crazy symbols instead of "Go ahead, say something..." I am guessing this has to do with the mismatch in rate?

Thanks again for your reply.

6

While I'm pretty sure you can get the HC-05 to work with a Macbook, I understand it is both difficult and pointless. You should trawl up Wabbitguy on this, he is the best source on Macstuff.

As for the baud rate, yes, both parties must be set the same. I don't know how this is done on anything but Windows wherein you simply set the rate in the terminal but, if there is no indication, it may be automatic.

I'm afraid I have had strife with desktop dongles too. I just take the wimp's way out and use a laptop with bluetooth installed, which works perfectly. I put it all down to the desktop, but it will run a bluetooth mouse OK.

Clearly the Arduino programme is kosher.

7

I am back to Windows system.

The Bluetooth dongle I am using immediately creates two incoming ports before I am ever able to pair with my bluetooth/arduino. I can't delete these 'incoming' com ports. Then when I create a new port, they are always 'outgoing'. In either case, the port is ALWAYS busy when trying to connect on my windows system. I tried removing these automatically created ports, but when attempting to create new ports, they always come back. Anybody working with the CSR Bluetooth dongle?

I am convinced that if I can create an 'incoming' port then it wont keep telling me its busy when I try to monitor.

Why is my bluetooth com port busy / already in use?