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Asked — Edited

Bluetooth Connection Error Firmware V16

Hi DJ & EZ-Robot community,

My Ez-Robot worked well in the old ARC version.
Today I installed the new ARC version.
The robot is not able to connect to Bluetooth.

I checked the tutorial about firmware update and Bluetooth connection.
I have XP 32-bit.
I have usb Bluetooth module (own software)
I do not have Microsoft Native Bluetooth program.
My bluetooth software show only one comport.
I think that is the problem.
Please help me!
Where can I download Microsoft Native Bluetooth program?
What can I do now ?

Thank you for your help


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Here is the log:

Attempting connection to COM7
Connection Failed: System.IO.IOException: The network location cannot be reached. For information about network troubleshooting, see Windows Help.

at System.IO.Ports.InternalResources.WinIOError(Int32 errorCode, String str)
at System.IO.Ports.SerialStream..ctor(String portName, Int32 baudRate, Parity parity, Int32 dataBits, StopBits stopBits, Int32 readTimeout, Int32 writeTimeout, Handshake handshake, Boolean dtrEnable, Boolean rtsEnable, Boolean discardNull, Byte parityReplace)
at System.IO.Ports.SerialPort.Open()
at EZ_B.EZB.Connect(String portName)

For what it's worth I ran the following test to see if any of the steps helped. No connection. Same log at beginning and end.

1. Windows 7 desktop computer. Only the Builder connection window (no code of mine). Robot tail-on at 10 ft, red and blue LEDs pulsing, clear line of sight from the kit bluetooth dongle to the robot.

2. Reduce range to 5 and 2 ft.

3. Exit Builder and reload.

4. Recycle robot power.

5 Restart computer.

6. Shut down computer.

7. Turn robot side-on.

8. Recycle robot power.
Sometimes it seems to be a range problem, but my laptop is only 10 ft from the robot.

Ten feet is too far away. The class 2 bluetooth is only good for about 3 feet.

30ft/10m is more like it. From Wikipedia (http://en.wikipedia.org/wiki/Bluetooth), and many other references):

Class Maximum permitted power Range(m)
(mW) (dBm)

Class 1 100 20 ~100
Class 2 2.5 4 ~10
Class 3 1 0 ~1

( "Basics | Bluetooth Technology Website". Bluetooth.com. 23 May 2010.)
I certainly agree with the data posted about the different class distances for bluetooth builder/designers. In actuality this does not seem to be the case. I should have stated the original comment in another way like "try moving the EZ-B closer to the PC and re-test".
wiki, really?....dude, real world results, i also vouch for the 3 foot range.

i havent updated my ezb in 4 months....v16 up and running and no unconnecting issues....unless i wonder away about 3-5 feet.
In any case, see Step 2 of my post where I closed to 2 ft; and the remaining steps were performed at 2 ft. My computer is on the floor with the robot directly in front.
Well I think I may have solved my immediate problem. I had taken the bluetooth dongle from my desktop computer in the den and plugged into my wife's laptop in the kitchen, where I would have more room for robot maneuvering. I had not installed ARC on that computer so I did it. It came up with COM7, whereas I had COM5 in the den. I had connection issues in the kitchen, but today I had NO connection back in the den. So in desperation I deleted EZ-Robot from the Windows Devices and Printers menu and reinstalled it using the tutorial procedure. Now I am back at COM5 and connecting. Whether it remains stable is another question.

I've still been having connecting problems. But I just stumbled on at least one cause of my connecting problem: the camera. If I turn it off I get solid connecting. If I turn it on I get connecting problems.

The camera is mounted in front of and a little above the EZ-B board. The wireless camera and EZ-Robot Bluetooth configuration both operate in the 2.4 GHz band. So interference is possible if not probable. I will look into shielding to verify that it is RF interference. If that is the case a two level robot would allow the camera to be either above or below the EZ-B with a grounded aluminum plate between. That should be enough isolation.
When connecting you'll want to disable tracking and any communication. If you're flooding the communication channel while trying to connect, some computers will have issues.:)

My robots all have their camera's mounted very near the EZ-B. Maybe you're experiencing interference - I haven't experienced it. Good to hear you have resolution!
I didn't mention that I have the camera connected to power and on-signal as you did in your tutorial. So to rule out conducted interference I unhooked the camera and EZ-B. Only the Connect window was showing.

The robot was at 10 feet aimed 180 degrees from the sightline. With camera on (running on camera internal battery) and camera off I ran two tests where I tried connecting 10 times. The results were the same on both runs for each case: 1 connect, 9 No-connect for camera on and 6 connect, 4 No-connect for camera off. I was surprised by the number of missed connects for camera off because earlier the percentage of connects seemed higher.

I then placed an aluminum shield between the camera and EZ-B. Whether the shield was ungrounded or grounded (attached to battery negative) the result was the same 7 connects for 10 tries with camera on (and 9 connects for 10 tries with camera off)). So the shield definitely seemed to help with camera on but can't say for sure in this limited test.

At 5 feet with no shield the result was 7 out of 10 for camera on and 9 out of 10 for camera off. (Same as 10 feet with shield.) So closer range seemed to help. But Bluetooth should certainly be good for 10 feet.

There has been so much variability in my Bluetooth connection from day to day and hour to hour that I can't say that for sure that camera radiative interference is a factor, but the above results do point in that direction. In one of your posts you talk about the variation in connection performance that you have experienced (and feel that the problem is in Windows); that is really discouraging.

I also can't help but wonder if there's a hardware problem with the EZ-B Bluetooth module or the Bluetooth dongle. I tried a test with my cell phone, which has Bluetooth capability. It finds the module but says it's only able to connect to headphones.
You might want to consider changing to a class 1 bluetooth network arrangement. That network will consist of a class 1 bluetooth USB dongle for the PC and a class 1 BlueSM1rf from sparkfun.com
I've never experienced a connection failure even when the PC is 50 feet away from the EZ-B.

Thanks! That's good info to know. It would be wonderful to have a reliable connection.

I would appreciate an answer to the following questions:

1. Were you experiencing serious connection problems at short (<10 feet) range before upgrading?

2. DJ says he's had problems with third party dongles. Which one is working for you?

3. Are you using the gold or silver spark.fun module?

4. How did you configure the 6 pins for EZ-B plug-in? I assume soldering is required.

5. Is the connection procedure the same as DJ's simple procedure?

6. Is connecting totally trouble-free now? (I believe you, but the info is so marvelous that I just have to ask!)


Please add your two cents worth! Think more power is the cure for all the connection problems?
1) I did not have luck trying to flash the EZ-B when I first got it because the EZ-B was in the shop and the PC was in another room.

2) I got the class 1 USB bluetooth from Amazon.com (Targus)

3) Gold (class 1)

4) I used a 6 pin header and soldered it to the BlueSM1rf module. The pinout is identical to the original class 2 bluetooth modules. Only the 4 center pins are used. The outer pin on each end is not connected.

5) Standard connection procedure using bluetooth association.

6) Yes

Contact me via email ( 1 have a few extra BlueSM1rfs) we'll negotiate a price.


I've still been struggling to solve my connection problem. Based on your experience I finally bought the SparkFun class 1 dongle and Gold modem, but no luck. I am getting completely random results in initially connecting and then maintaining connection. The worst part is the dropped connections, making it impossible to enjoy my robot. So now I have bought a FTDI USB-TTL serial cable to eliminate Bluetooth and see what that tells me. Unfortunately, I now have another connection problem: I can't connect and I get the error message saying I have the EZ-B V8.5 firmware and need to upgrade to V16 (which I already have). I'm going to write a new post on this problem if you want to follow my trials and tribulations.

I want to thank you for your above response and offer. Much appreciated.
Sorry, I've never said there is an issue with third party dongles. In many cases, third party dongles have a higher distance than embedded antennas. Please re-read what I had written regarding the third party item that does not work. Specifically, the third party item that does not work is "Bluetooth Stack" or "Bluetooth Software".

The MS Windows Bluetooth Stack is the only supported software for EZ-Robot. This is because it is the only software known to work properly. We don't have access to the source code of any Bluetooth stack (Microsoft or third party) , so we have no idea why they are different. The only thing we know is they are different:)

As for your connection issues with the FTDI reporting V8.5. There can be a few causes with this. Either the module has ECHO enabled. Or, the RX/TX are connected backward. Or, they TX and RX have been shorted and the chip is damaged.

There is no reason to start a new thread on the same topic.

Perhaps post your ARC Project file in this thread. Maybe there is something strange in the project file that is causing the disconnect? You can post a project file by using the "ATTACH FILE" option to the right. Brose for your file, and press UPLOAD.

Also, we cannot diagnose any issues with an EZ-B if there are peripherals connected. This means, the only way to truly test is to disconnect all peripherals from the EZ-B. No servos. No LEDs. No Motor Controllers. Nothing. There can be nothing connected to the EZ-B.

If you can, i'd like to see a photo of the bottom of your EZ-B. On occasion, with so many boards being hand built - there is the odd one with a missing solder joint. Funny thing, it's usually pin #1 on the chip too. We've had a 2 or 3 with pin #1 not soldered.

We'll figure it out for you:)
1. Dongle/Stack. I let Windows 7 install the driver automatically, so should be the right stack.

2. Echo. I don't see any way to check Echo enable using Device Manager. Otherwise: 9600 baud, 8 data bits, 1 stop bit, no parity, and no flow control.

3. Tx/Rx connections. Cable Tx to EZ-B Rx and Cable Rx to EZ-B Tx. No shorts on Cable header connector and the EZ-B Rx,Tx,5V, Gnd pins are visually well isolated (except for the 5V bridge). (The 5V and 3.3V pads are uncomfortably close but an ohm-meter shows no connection.) Can't speak for chip damage.

4. New thread. Sorry, already started one in Hardware thread. I thought an isolated discussion of this problem would be easily found by others. (Take a look at the site. Do the replies seem useful to follow?)

5. Project file. I was doing my testing with only the Connection Control pulled up.

6. Peripherals. I disconnected everything (two servos, one ultrasonic ranger, and one camera). Still have the problem.

EZ-B Photo (Looks good to me!):

User-inserted image
I had the same problem until i update the firmware in the firmware tutorial.

Then i check it at 100 feet away and still work perfect.

I did use a better bluetooth dongle that came with EZB ,that be part of the reason i have a long range

But only check 1 of my 20 EZB'S i bought ,most likely will need to update the firmware in the rest of them.
Also best way to test for bad connections,since some are on top ,it with a 40 pin ic clip and a meter.

Only connections need on the board to get communication is v+,gnd,mclr,2 clock (crystal ) and tx and rx ,

I dont have the data sheet of the microprocessor used in EZB here where i am at,to tell you the pin #.


My problem turned out to be in the EZ-B board. I broke down and ordered a replacement. Don't know what the problem was, but now having no connection problems.