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Asked — Edited

Help! Bluetooth Connection Questions With New Ez-B

Hi Everyone,

After accidentally finding this site while looking at Roomba reviews on YouTube I decided that I really needed to build a robot. My wife just got the complete kit for me as a birthday present so my children are awaiting the immanent arrival of a robot in our house. The trouble is I cannot get the EZ-B to connect to ARC or do a firmware update. I've trawled the forum and seen similar issues but never an actual fix for the problem, hopefully I've covered all the obvious stuff in my post (sorry it's so long).

So far the steps I've taken are...

I've paired the EZ-B with my laptop (running windows 7). It shows up under Bluetooth devices as linvor. COM6 and COM7 were shown as the ports when it connected

At this point on the EZ-B I have a flashing red light (Bluetooth module) and a solid blue light.

In control panel \ device manager under Bluetooth radio it shows Microsoft Bluetooth Enumerator, Driver provider for this is Microsoft. and Dell Wireless 365 Bluetooth Module, Driver provider Broadcom So I think I'm using the right Bluetooth stack everything looks like DJs tutorial video when I paired the EZ-B, can someone confirm?

Next I opened ARC selected COM6 in the drop-down for connection 0. Pressed Connect. Red light stops flashing briefly and I got this message...

Attempting connection on COM6 Comm Err: The operation has timed out. BbytesToExpect: 1

Received: Disconnected Connection Failed: System.Exception: Controller Not Responding at EZ_B.EZB.Connect(String hostname, String tcpPassword, Int32 baudRate) Disconnected

I went back and read/watched the online support/tutorial. I tried firmware update (I think I need this since device name is linvor and I have a flashing blue not 'pulsating' when it's not connected to bluetooth), got similar message.

At his point I went back to online support again and tried the 'hardware diagnostic', the board passed resistance and voltage tests.

So at this point I think I've exhausted all the resources currently on the website. Any help you can give me to get this up and running would be greatly appreciated. Looks like it'll be a great bit of kit if I can ever get connected!



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How many times did you try to connect with ARC and the firmware updater? It can be a little hit and miss on occasion and take a few tries.

@Technopro, you can't pair it incorrectly, it either is paired or it isn't.


@peter_d77 If you still can't get it to after trying what @Rich mentioned you can also try re-seating the bluetooth module on the EZ-B, carefully pop it out of it's socket and pop it back in. It could be just an intermittent connection at the 4-pin female bluetooth header.


I know the rule is to normally use the lowest com port but have you tried using com 7 ? Also have you tried establishing a connection using another terminal program like Hyperterm or Realterm ?

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Thanks for all the quick responses...

@Rich I couldn't give the exact number of tries but it's a lot, I tried several times over two days.

@Robot-Doc I had COM6 and COM7 available, I tried both. These were the only two ports available in the drop down since I've removed all other Bluetooth devices in case there was any conflict. I've never used Hyperterm or Realterm, how would I go about this?

@skater_j10 I've checked the resistance of the pins on the Bluetooth modules, they are behaving as described in the hardware diagnostic section on this website


Peter, i'm sorry to hear about your issue. Before we consider the unit faulty, can you please examine the back of the circuit board? Look for a connection that has not been soldered. On occasion, this has happened... Usually it's one of the pins on the IC (usually at each edge).

Can you verify that the Blue LED is flashing?

If all looks fine and the blue LED is flashing... Then we will have to replace your EZ-B. There have been a few occasions where the IC was statically damaged during shipping. It has happened nearly 5 times in the past year - however, this is an acceptable tolerance from thousands of shipments. I wish there was something more we can do, but it creeps up on us from time to time.

I can tell from the description that the Bluetooth connects and disconnects without communicating to the IC. Also, you mention the EZ-B is still being recognized as LINVOR and not EZ-Robot. On first connection, it will be recognized as Linvor. Following all other pairing, it will be recognized as EZ-Robot.

Contact Us to have your EZ-B returned to our location and we'll send you a replacement - if the blue led is not flashing, and all traces appear to be soldered.

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Hi @DJ Sures, thanks for response.

I've just visually checked the board all connections appear to be soldered and look good to my untrained eye.

The blue LED starts flashing fast when I power up the EZ-B then it stops flashing (I think once it connects to the laptop?). What does that mean?


peter_d77 - "I've never used Hyperterm or Realterm, how would I go about this?"

Those two programs can be downloaded from the web. Just do an internet search for them. I use either one since they both work the same, they just have different screens depending on what you like. They can be used to perform basic troubleshooting in the case of EZ-B and bluetooth. You just specify which com port you want to connect to (in your case 6) and then see if the connection is established.

You will not have to do this test though since DJ mentioned that he suspects your board has a damaged IC due to ESD.


I have a similar problem, and my blue led is not flashing, the pins seem to be soldered well enough. Its only the red led which flashes on and off


@emalinga, you need to go through the troubleshooting steps located in the Support tab since the Blue LED is not flashing.


My Blue LED also does nothing. I'm powering the EZ-Bv3 from a 7.2v rechargable pack (it's fully charged). When I first powered it up I got the red flashing LED from the bluetooth and nothing from blue LED.

I paired my bluetooth device, went to connect under the ARC version 2013.06.04.00 software and was informed I need to do a firmware update. I followed the video instructions from support and completed the firmware update successfully.

I reconnected to the EZ-B board in the ARC and it shows connected. But never durring any of this does or did the blue LED do anything. It's never been on, flashed, blinked, nothing.

I really wanted my blue LED to light up stress confused Any thoughts on what the issue might be?

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Yes unsolder the blue LED and turn it round. From the rear of the board the LED should look like this User-inserted image


It appears that your board is working, just the LED is not turning on. Check for a cold solder joint on the underside of the printed circuit assembly board.


@winstn60 When I saw your reply I thought Ah-HA, has to be the issue. But when I look at my board from the rear as in your picture the LED is in the same directional placement as yours (my LED matches your picture). So, I don't think I want to flip it around. But thank you for the picture! :D

I powered up the board and flipped it over and checked the voltage pins on the back as suggested in troubleshooting and I get the correct voltages. With my board flipped over and the LED towards the top left side and I put my meter on the LED as follows (positive RED lead to the left outmost LED pin) and (ground/negative BLACK on the right inside most LED pin) I get fluxating voltage reading close to these that follow: .5, 1.2, 2.8, 3.5, 4.2V And it just cycles back those readings up and down.

Those readings make sense to me if the blue LED should be pulsating before the board is synced via bluetooth (which I believe is correct).

Tomorrow I'll try resoldering the LED to see if it is a cold solder joint. :(


Well, I couldn't sleep, so I resoldered the LED and sure enough, it was a bad solder joint. @Robot-Doc, thank you! My blue LED is working just fine now.

In the words of ESPN sports channel "C'mon Man!"
Ya can't have the diagnostic LED not soldered in, right off the bat it looks broke. stress Fingers crossed that's the last and only bad solder joint.

Have you guys seen other bad solder joints elsewere on your boards?

@winstn60, did you have to filp your LED around?

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Hi Justin no what I meant was the way the picture shows is for a working LED. Only flip it around if the anode larger land inside the LED is the opposite to my pic

Glad you got working good bit of fault finding. I had a pin not soldered but that was in the very early days of the EZ-B


@JustinRatiff I've been running two different EZ-B boards and have had no issues with construction faults or assembly errors. These boards are built well for the most part. The one important consideration is failure due to ESD which can be avoided with proper grounding procedures in your work area.