Trying to connect via Bluetooth.

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

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brentp
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Post by brentp »

Yes, you would need to supply 3.3v, GND and 3.3v level RX and TX to the module from your PC, then you can issue the commands to change the baud rate.
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Alex B
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Post by Alex B »

Cool, the module I have can operate both on 3.3 and 5 volts so that makes life a bit simpler (that is, if the wretched thing is still alive.......).

alex

Alex B
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Post by Alex B »

Right, so I scored some old connector cables and got creative with the soldering iron. The BT-module is now connected with the RX-TX TX-RX pins of the COM port and gets 5 volts from a USB connection. I can program ports with Tera Term but I have no idea if I am only changing baud rate at the COM-port connection or if it is really done to the module. Never mind that now, what is more worrying now is the potential risk that I can't connect because the ports won't meet. The module connects itself through a newly installed COM40 port, while the Megajolt program doesn't go higher than COM20 :( . Is there a way to expand the number of COM ports in the MJ program to 40 or at least create an extra port?

Alex

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Post by brentp »

depending on the bluetooth module you have there is a certain command for setting the baud rate, BT name and password.

For setting the COM port, you can use device manager to force switch the COM port windows assigns to a virtual com port device, like a USB to serial adapter or BT adapter.
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bobclevenger
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Post by bobclevenger »

I believe the problem is that one can only use the AT command set from the wired side of the BT module, that is, the side that is connected to the MJLJ module. The name can be changed from the wireless side of the connection, but nothing else. Am I mistaken?

Oops, I missed a few posts here.

Regarding the COM 40 problem. Yeah, that happens when you keep trying to make a BT connection. Windows does not have a neat solution for removing or renaming unused COM ports. It can be done but it's really stupid.

Go into device manager;
Expand [Ports (COM & LPT)] -- you will see a list of COM ports;
Select COM 1;
Click on the Port Settings tab;
Click on the Advanced button;
At the bottom you will see a box with the COM port number in it (it will say "COM1" at this time);
Click on the down arrow at the right of this box;
Click on any unused COM port that's easy to remember (such as COM99);
Click on OK;
Click on OK in the box that follows;
You have now successfully renamed COM1 to COM99.

Using this process rename COM40 to COM1;
Rename COM 39 to COM1 (if Windows asks just click on YES or OK);
Continue renaming unwanted COM ports to COM1 using the same process.

After you have finished renaming all the unwanted COM ports, use this process to rename COM99 (or whatever number you chose to rename COM1 in an earlier step) back to COM1.

Now all your unused COM ports should be freed up and COM1 is back where it was to begin with.

It's been a while since I did this on my own computers, but I think I have remembered all the steps.
Last edited by bobclevenger on Fri May 09, 2014 3:15 am, edited 1 time in total.
...Bob

brentp
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Post by brentp »

That is correct - you have to change the baud rate from the wired side.

bobclevenger
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Post by bobclevenger »

Just a bump to let you know that I added some stuff to my last post.
...Bob

Alex B
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Post by Alex B »

Changing COM1 to another number went ok, but then the doodah hit the fan. When I try to work on the BT COM-ports the Port Settings tab doesn't show :evil: . Could it be because I am running Windows XP (without SP3 added)?

Alex

brentp
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Post by brentp »

Honestly do not know. There are so many variations of windows and service packs. Did you get the baud rate changed on the bluetooth module to 38400?

Alex B
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Post by Alex B »

Don't know. Bluetooth is a big black hole for me. I tried something with Tera Term but if that changed the baud rate?...... I saw some clips on Youtube that show how you can check if info is transfered, but I haven't come so far that I think I can try it.

Alex

bobclevenger
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Post by bobclevenger »

Alex, that method I posted for removing unused COM ports is for Windows 7.
For Windows XP try this link -- http://www.ehow.com/how_6216286_remove- ... ws-xp.html
...Bob

Alex B
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Post by Alex B »

Thanks for the link Bob, will try that. But first to get into the BT module on the wired side. I saw some clips on Youtube and it gave me the impression that it is possible to connect via a USB connector. But are the connections D+ and D- on the USB connector interchangeable with RX and TX on the BT module? Or are the communication protocols completely different?

Alex

bobclevenger
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Post by bobclevenger »

I believe they are different protocols.
I have ordered an adapter from eBay that should allow me to use a USB port to connect with the TTL serial data on the wired side of the BT module. It was cheap enough and when it arrives I shall try this once again. The link for that adapter is --

http://www.ebay.com/itm/310742466145?ss ... 1497.l2649

-- be aware that I haven't tried this yet. I'll update after I have tried it.
...Bob

Alex B
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Post by Alex B »

After I asked the question I found out myself that the answer is no :( ; when I hooked the module up to the computer through an USB connector a message popped up that an unknown USB device was detected. After that and some browsing on Youtube I found a video that mentioned using a FTDI board, which connects between a USB port and the BT module. On Ebay I found things like this:

http://www.ebay.co.uk/itm/FT232RL-FTDI- ... 5113wt_983.

A lot of BT diy gadgets loom up that are connected to Arduino. I'll wait for your result first Bob. Maybe the cable you on order has some hardware in the back of the connector, if not then it is only a connector cable for hooking up to an Arduino mother board (which also has the ability to communicate with BT modules).

Alex

Alex B
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Post by Alex B »

If only things were simple for once. The Administrator's password is in safe mode different from normal mode :evil:. I am using an old laptop from work and there hasn't been proper registration of all the passwords :( . Time to try the even older and slower laptop with SP3 installed and a limited BT function. Never give up without a fight :!:

Alex

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