[SOLVED] Problem while Pairing with HC-05 BT Module

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#1
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Hi,

 

I am using ATSAMD10c14A processor to pair with HC-05Bt module.

 

First, I connected my SERCOM pins to UART->USB module and tested the connectivity with my PC. I was able to send/receive data from pc.

 

Then I connected the SERCOM pins to HC-05BT

MPU         HC-05BT

Tx  ---------- Rx

Rx ----------- Tx

 

Now when I power up my board having KEY pin of HC-05BT LOW, I see the HC-05 Bluetooth is shown in my Mobile and i could even pair with.

However while power on if I pull the KEY pin HIGH (to enter to command mode) I see the HC-05 Bluetooth profile in my mobile but unable to pair with.

 

Is it so that HC-05 can not be paired in command mode?

 

Is the Tx-RX (cross) connection right? or it should be Tx--->Tx and Rx---Rx (looks illogical but :()

 

Thanks

/SP

Last Edited: Sun. Oct 23, 2016 - 11:51 PM
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As far as I know, HC05 cannot be used for basic Bluetooth in command.

Command mode is just for configuring the HC05 module.

The baud rate for HC05 in command mode is 38400 bps.

Once configured, switch it back to data mode to send data from mobile and vies-versa.

Tx and Rx connections should be interchanged. Just go through the schematics of the HC05 base board if you are not using the bare module. (just to rule out any possibility of printing errors.)

Silly beans are always silly
:)

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You can take a look the below mentioned link.

http://www.rhydolabz.com/wiki/?p...

 

The link is for one of their modules, but it might be helpful in this case.

enlightened

Silly beans are always silly
:)

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Thanks for response! I will have a look at the link.

 

/SP

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I am now able to communicate to the HC 05 module in AT Command mode and also issue commands to which I receive proper response as well.

 

To achieve this I have connected KEY to VCC and restarted my board. The default baud is 38400.

After entering to command mode I changed the Role, Baud to 38400 (Once again, though same).

 

To pull KEY HIGH and LOW I have installed a switch. Also I am using my android phone installed with Bluetooth Terminal application to receive the data.

 

After AT commands I pulled down KEY switch and connected it to GND. Now As soon as I restart my board, my mobile is able to see the BT and connect with it.

 

Since my baud is same I simply continue sending some Text in while loop but I dont see any text being received by my phone terminal.

 

Have I missed any thing to setup HC05? Since AT commands are responding fine, my UART interface is working fine

 

What else could be the culprit?

 

I appreciate any help/pointers to resolve this issue.

 

Thanks

 

/SP

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Could you please let me know the bluetooth android terminal used?

Silly beans are always silly
:)

Last Edited: Sat. Oct 22, 2016 - 06:04 AM
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I am using "Bluetooth Terminal" android application. The snapshot is attached.

 

/SP

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Try restoring the device back to its initial configuration & then try to connect to your mobile.
It should work fine.

AT+ORGL

Default state:

Slave mode, pin code :1234, device name: H-C-2010-06-01 ,Baud 38400bits/s.

 

Again if the issue persists, then we will go deeper.

yes

Silly beans are always silly
:)

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you mean restore the default and do not need to change any settings but directly go to communication mode and try sending the data?

 

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Yup. Exactly.

By default, hc 05 will work in slave mode with baud 38400

Silly beans are always silly
:)

Last Edited: Sat. Oct 22, 2016 - 09:08 AM
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I tried the suggestion and to mu surprise it worked!!

 

Could you please explain me what could have been wrong?

 

Earlier I did set it to master mode and couple of other settings!!

 

/SP

Last Edited: Sat. Oct 22, 2016 - 01:41 PM
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It seems I missed to assign the LINK address since I was operating in master mode.

My understanding was that in master mode also HC05 can connect to any of the slave available but I had to provide LINK address.

 

@Harikrishanan, many thanks!! it was turning point indeed. Thanks Again.

 

/SP
 

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Well, thats great.

yes

I assumed you were working on slave mode.

Anyway, good work.

smiley

Silly beans are always silly
:)

Last Edited: Mon. Oct 24, 2016 - 09:16 AM
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Dear friends, 

I purchased two HC-05 from Amazon. I have to use BT module with Arduino Nano.

I have connected Nano board to PC through Programming USB cable. 

Supply of 5V and GND connected to BT module that is taken from Nano board.

But LED on BT module not blinking and not showing in mobile application after SCAN of bluetooth. 

What can be possible errors?

Both module are not blinking.

Is there any way to know that they are in good condition or I got these already faulty?