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October 2011


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Andy Traiger <[log in to unmask]>
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Andy Traiger <[log in to unmask]>
Thu, 27 Oct 2011 21:18:30 -0400
text/plain (3933 bytes) , text/html (12 kB)
On another thread some coaches were mentioning having trouble with Bluetooth
problems.  We have loads of trouble with our Bluetooth connection.  However,
the time saved in developing our software missions when the Bluetooth
connection is working makes it well worth the time it takes to get the
connection started.

Here is a procedure for connecting to the NXT with Bluetooth that we have
found very useful.  I copied this from the NXT Step Blog found here:


I don't have the Bluethooth USB adapter that LEGO sells.  Instead, I bought
the cheapest one I could find (about $10).  The Bluetooth connection to the
NXT is very finicky on our computer, but if this procedure is followed we
can establish a connection most of the time.  I've heard that the LEGO
adapter will cause less trouble than a generic adapter like I have.  I don't
really know if this is true since I don't have one to experiment with.


Here's the procedure that I copied from thenxtstep:


Switch on the PC

2. Slide in the Bluetooth dongle (my PC doesn't boot with the dongle

3. On the PC, open the Bluetooth Devices window

4. If any NXT device is listed in the Devices list, Remove it (otherwise, a
'Line Busy' error will pop up later). Make sure 'Turn discovery on' is
selected. Close the Bluetooth Devices window.

5. Switch on the NXT, and select 'Search' from the bluetooth menu, then
'Connect' to the found computer. Accept the passcode [1234].

6. On the PC, a window comes up mentioning that a Bluetooth device is
requesting to connect, asking if you want to allow connection. Click on the
message to allow connection. A new window pops up, asking for the passcode.
Type in the passcode and click Next. Again, the NXT beeps to verify the
passcode; press the orange button on NXT to accept.

7. Open the Bluetooth Devices window. Select the NXT device and press
'Properties'. In the new window that opens, click the 'Services' tab. Now,
Windows starts searching for services that NXT supports. Select all
available services (in my case, two serial ports) and press OK. Windows now
installs some new drivers. After that, close the Bluetooth Devices window.

8. Now, start the Mindstorms software on the PC, and open the NXT window.
Scan for NXT devices, and after finding NXT, click "Connect" (if not already
connected during scanning).

9. YES! It works! (for me anyway).


Some comments:

 Steps 1 and 2 are not necessary for my Bluetooth adapter / Version of
Windows 7.  But I've found steps 4-6 are critical to establishing / fixing a
connection that used to be working but isn't working any longer.  I have
also found step 7 is not necessary to get my Bluetooth adapter talking.
Sometimes, even this procedure fails for me.  I've found that shutting off
Bluetooth on the NXT brick (something everyone should do before they bring
their robots to the tournament!) and then turning it back on again fixes the
problem and then I go through the procedure above to get things going again.
Sometimes when the LEGO robot shuts off automatically, you can just turn it
back on and get it talking again.  Other times, it is necessary to go
through steps 4-8 (skipping 7).


I hope this helps those of you teams that are struggling with Bluetooth


Andy Traiger

Vienna Robotics


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