Connecting two Bluetooth HC05 to each other using one arduino

Projects General Guidance
1

I want to connect the two bluetooth HC-05 to each other using one arduino.

The Master Bluetooth properties:

VERSION:5.0-20220104

+ROLE:1

+UART:38400,0,0

+ADDR:5856:00:0029E9

+CMODE:1

+BIND: 1B00:3:412360

The Slave Bluetooth properties:

+VERSION:hc05V2.3_le

+ROLE:0

+UART=38400,0,0

+ADDR=1B:00:03:41:23:60

+CMODE:FAIL (For some reason when i type AT+CMODE=0 it outputs "FAIL")

+BIND=00:00:00:00:00:00

How I set them up separately using the same arduino:

VCC to 5V, GND to ground, EN to 3.3V, TXD to TX, RXD to RX

After that I wanted to test them out if they would connect:

I only connected the VCC and the GND of the two bluetooth HC05 to 5V Batteries, but they don't sync they just keep on blinking rapidly. Do I need two arduinos to to also connect the TX and RX of both of them?

2

There are good examples, some written by Robin2, how to communicate wirelessly. I know there's RF and likely BT too.

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3

There is a for hire section if you do not want to do the design.

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4

I'm new to the community so I'm not familiar with anyone named Robin2. Could you please send me some source links for the good examples you're talking about which I can look into ?

5

They should "find each other" with only power connected.

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6

For searches in forum there's a function up in this window, dark green, with the text "Search Forum"!

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7

I recommend Martyn Currey's site. Example page:
https://www.martyncurrey.com/arduino-with-hc-05-bluetooth-module-in-slave-mode/

You MUST use logic level shifters when connecting 5V outputs (TX) to Bluetooth inputs (RX).

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8

So this is what I meant by only connecting the VCC and the GND of the bluetooth HC05. (The one connected with the blue and orange wires is the Master)

I can easily connect them to a phone or my laptop, but I can't get them to connect to each other

9

The unit that got the BIND treatment should be bound to its 'partner' and mot otherwise pairable

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10

So what you are saying is that the Master should be bound to the Slave ? What do you mean by "bound"? Do you mean that I should connect the TX and RX of the Master to the RX and TX of the Slave?

11

One you do the BIND operation on, the other gets no special prep - as I recall.

The one that gets the BIND operation, I wouldn't figure as pairable with anything but its assigned address ("partner"). I believe you posted that you could still pair connect with both your units

I followed the martyn currey article/s on this.

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12

https://www.martyncurrey.com/connecting-2-arduinos-by-bluetooth-using-a-hc-05-and-a-hc-06-pair-bind-and-link/

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13

Don't think that is possible.

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14

It's silly and pointless, but can be done in order to just prove it can be done. One way is to have one on hardware serial and the other (presumably) on 9600 baud software serial, and text to be transmitted included in the programme. I suppose it can be used to confirm Blueteeth are properly configured.
See post#5. I understand master finds slave as soon as the latter is powered.

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15

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