Problem cant' connect BT module to Multiwii pro w GPS!

andrea

andrea

Member
Hello
I bought a bluetooth module:
http://www.banggood.com/MWC-Multiwii-Bl ... 86049.html

Connect it to my quadcopter
Start the program " multiwii " on the android device, press connect ( the red light stop blinking) but no data arrives, can't see the pid etc...
I think the baud rate is the problem , but if i can connect the phone to the BT should the baud rate correct ?
I mean if the baud is incorrect i can't create a connection with the phone.
Please help me !
 

Motopreserve

Motopreserve

Drone Enthusiast
Sounds like the baud rate is incorrect. It should be 115200. You'll need to change it with arduino. IIRC, Bluetooth modules usually ship at 9600.
 

andrea

andrea

Member
I tried a lot to change the baud rate with Arduino but when i send AT command nothing appears
I spend a lot of time travelling on the web but nothing seems to work! :(

I tried to change baud rate by following this video and similar :
 



Motopreserve

Motopreserve

Drone Enthusiast
If I recall correctly, you need to change the baud rate in the sketch, and then flash it to the Bluetooth board.

I'll see if I can watch the video if I get time later. But if nothing has been written back to the board, no changes have been made permanent.
 

Motopreserve

Motopreserve

Drone Enthusiast
Sorry, by opening that window and hitting "send" you are compiling that info to the board. So if you've followed the instructions, I'm not sure what the issue would be.

Does it not shoot back "OK" when you type AT?
 


Motopreserve

Motopreserve

Drone Enthusiast
That means it's not connected to the computer.

And I'm assuming you've double checked the way the FTDI is connected? It's a little strange with the swapping of the 2 leads.
 

andrea

andrea

Member
The connection between arduino and computer is ok...The sketch " hello word " works.
but i dont'know why if send AT command there is no OK coming back.

maybe I'm doing something wrong...please tell me!
 

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Motopreserve

Motopreserve

Drone Enthusiast
I believe that the lower right box showing 9600 means that no change has taken place to the board. So somehow you need to determine why the board is not fully connected to the arduino program. It may be connected to the computer (recognized by the COM port), but not correctly connected to the software.

Are you sure you have the wires switched from FTDI to Bluetooth module???
 




Motopreserve

Motopreserve

Drone Enthusiast
Sorry, I'm at a loss. I used a cheap FTDI board to do the connection - so I am unfamiliar with the arduino connection setup.

One thing is clear - there is not a correct connection to the computer. So maybe try to trace that. You may have luck on the arduino forums? Also, we may need @econfly He is a wizard with Arduino :)
 

Motopreserve

Motopreserve

Drone Enthusiast
Go back and watch that video. It looks as if you have the Tx going to Tx, and Rx going to Rx. These need to be flipped usually. I believe the diagram he shows demonstrates this.
 

andrea

andrea

Member
WORKS !!!!!!
The problem was only the tx and rx connected like : tx>tx and rx>rx
but following the video i see clearly that the connections are inverted!
It was something I took for granted !!
THANK YOU VERY MUCH for help me!
Maybe whith out your help I would not be able to see this problem
...Now i can finally set all the PID easly and quickly:D
 




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