Bluetooth HC05 - blinking twice every 5 seconds

hi, my bluetooth module hc05 is connected to arduino via a straight rx-rx and tx-tx connection.
I have 2 modules, and to pair them with each other i used how to mechatronics' video as guidance. I configured them both and seem to be connected, but the master module's LED is blinking twice every 5 seconds.

ALSO, the master is an arduino UNO and the slave is a NodeMCU esp8366, both have straight serial connections and both seem to connect.

configuration:

MASTER:
AT+name=HC05 1 //OK
AT+pswd=1234 //OK
AT+bind=98d3,31,80528d //OK
AT+role=1 //OK

SLAVE:
AT+name=HC05 2 //OK
AT+pswd=1234 //OK
AT+role=0 //OK

i tested the code that was in the tutorial but i couldn't get it to work.

PLEASE HELP!

samythegamer:
hi, my bluetooth module hc05 is connected to arduino via a straight rx-rx and tx-tx connection.

Now think about it… RxRx. Transmitters transmit, and the thing they need to transmit to is a receiver. You might also rethink any configuration you have done because, with connections like that, you probably haven’t, you are just kidding yourself. And, as for the connection, I guess “seem” is the operative word. Further, I believe AT commands are in capitals. You might also note that it is actually possible to have Blueteeth connect with each other, but that does not guarantee any connection with their respective Arduinos

Nick_Pyner:
Now think about it… RxRx. Transmitters transmit, and the thing they need to transmit to is a receiver. You might also rethink any configuration you have done because, with connections like that, you probably haven’t, you are just kidding yourself. And, as for the connection, I guess “seem” is the operative word. Further, I believe AT commands are in capitals. You might also note that it is actually possible to have Blueteeth connect with each other, but that does not guarantee any connection with their respective Arduinos

I found the tutorial.

The Tx <–> Tx, and Rx <–> Rx is for using the Mega as a USB-TTL converter.
The tutorial is directly commanding the HC-05 by typing commands in Serial Monitor.

I suspect that once that is done, the tutorial neglected to reverse that so that his code can work.

Also the tutorial neglected to explain that the HC-05 needs to be taken out of AT mode and back to data mode.

In addition the tutorial is using Serial. With the Mega’s additional 3 hardware serial ports, the main serial port should be used for debugging and one of the others used for the HC-05.

Bad tutorial.
.

ieee488:
I found the tutorial.
The Tx <–> Tx, and Rx <–> Rx is for using the Mega as a USB-TTL converter.
Bad tutorial.

Thank you, I won’t bother asking what that is all about, but there is a faint possibility that it explains the LED activity.
@OP, you might check the Martyn Currey website. He actually knows what he is doing, and specifically addresses Arduino<>Arduino comms via Bluetooth.

Nick_Pyner:
Thank you, I won't bother asking what that is all about, but there is a faint possibility that it explains the LED activity.

The first part of the "tutorial" is about changing some of the HC-05's configuration.
I remember doing that when I wanted to change the Name and the password for the HC-05.
Easiest to do by using USB-TTL adapter that I have.
The writer of the tutorial is using the Mega as a USB-TTL adapter.

The OP writes that the LED blinking twice every 5 seconds.
Not sure what that means.
.

ieee488:
The OP writes that the LED blinking twice every 5 seconds.
Not sure what that means.

I believe what that means is that I was wrong, and the configuration was actually successful. Blueteeth can actually talk to each other, but they cannot talk to their respective Arduinos.

The "connected" signal varies between breakout boards. It used to be steady on, and I believe that is still usually the case. I assume OP has a ZS-040, which I thought gave a double blink every two seconds, but every five makes more sense. This implies that the LED is programmable, but I have never seen the AT command for that.

Nick_Pyner:
I believe what that means is that I was wrong, and the configuration was actually successful. Blueteeth can actually talk to each other, but they cannot talk to their respective Arduinos.

The "connected" signal varies between breakout boards. It used to be steady on, and I believe that is still usually the case. I assume OP has a ZS-040, which I thought gave a double blink every two seconds, but every five makes more sense. This implies that the LED is programmable, but I have never seen the AT command for that.

If they are paired, then it means that the connection now needs to be switched RX--TX and TX--RX so that the Arduino can communicate with the HC-05.

I gave away my HC-05s. Now I want an Arduino with Bluetooth. Less hassle.

.

ieee488:
The OP writes that the LED blinking twice every 5 seconds.
Not sure what that means.
.

My HC-05s blink rapidly when not connected to another BT device (looks like twice per second).

When connected to a another device, they blink twice every 5 seconds.

John.