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I am trying to connect a HC-05 Bluetooth Module (connected to Arduino Uno) to my Raspberry Pi 3 in the hopes of achieving bluetooth communication between the two to send data from the Uno to the Pi.

Trying to use Bluetoothctl to pair, connect and trust the HC-05 device seems to fail for me.

[bluetooth]# power on
Changing power on succeeded
[bluetooth]# agent on
Agent registered
[bluetooth]# scan on
[CHG] Device 98:D3:31:FB:6F:F1 LegacyPairing: yes
[CHG] Device 98:D3:31:FB:6F:F1 RSSI: -43

[bluetooth]# pair 98:D3:31:FB:6F:F1
Attempting to pair with 98:D3:31:FB:6F:F1
[CHG] Device 98:D3:31:FB:6F:F1 Connected: yes
Request PIN code
[agent] Enter PIN code: 1234
[CHG] Device 98:D3:31:FB:6F:F1 Paired: yes
Pairing successful
[CHG] Device 98:D3:31:FB:6F:F1 Connected: no

[bluetooth]# connect 98:D3:31:FB:6F:F1
Attempting to connect to 98:D3:31:FB:6F:F1
[CHG] Device 98:D3:31:FB:6F:F1 Connected: yes
Failed to connect: org.bluez.Error.NotAvailable
[CHG] Device 98:D3:31:FB:6F:F1 Connected: no

[bluetooth]# trust 98:D3:31:FB:6F:F1
[CHG] Device 98:D3:31:FB:6F:F1 Trusted: yes
Changing 98:D3:31:FB:6F:F1 trust succeeded

Here is the info prompt.

[bluetooth]# info 98:D3:31:FB:6F:F1
Device 98:D3:31:FB:6F:F1
        Name: HC-05
        Alias: HC-05
        Class: 0x001f00
        Paired: yes
        Trusted: yes
        Blocked: no
        Connected: no
        LegacyPairing: yes
        UUID: Serial Port               (00001101-0000-1000-8000-00805f9b34fb)

Specifically the error I am getting is "Failed to connect: org.bluez.Error.NotAvailable"

I am not sure how to get pass this error and I am unable to complete my project without confirming a linked bluetooth signal between the two microprocessors.

Thanks, Aditya

2

Try to install the blueman pack using sudo apt-get install blueman, or, if you have it installed, try

sudo apt remove blueman
sudo apt update
sudo apt upgrade
sudo apt-get install blueman

After one of this processes, run blueman or go to the Menu > Preferences > Bluetooth Mananger, then, search HC-05, add it to the Trust List, insert the password (normally 1234 or 0000) and connect it by clicking Configure.

If the problem persists, the problem is with the HC-05 module, try to connect it to an Android, if it doesn't connect, you will need to buy a new one.

| improve this answer | |
2

You do not need to connect with Bluetoothctl. With Bluetoothctl, use exactly most commands as you show; then after pair, leave this window but not close. Open new terminal and use

rfcomm bind rfcomm0 98:D3:31:FB:6F:F1

But note: there is still no connection at this stage. To make real connection, use something to connect to your new serial port, like

screen /dev/rfcomm0 9600,cs8,-parenb,-cstopb,-hupcl  #  use ^a, k to exit.

Try send some chars with keyboard. After 2-3 seconds, you find your HC-05 connected by its LED. And look at your first window where Bluetoothctl runs. It will show that your HC-05 is connected. Thanks.

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  • Thank you, this is exactly what I needed! Note for others, you can quickly check if you are getting data (assuming your bt device is just always streaming) with cat: cat /dev/rfcomm0 . If you see data there you should be able to communicate with the device using a library like pyserial. – jminardi Oct 7 at 23:42

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