Bluetooth keyboard

This article describes how to set up a Bluetooth HID keyboard with Arch Linux, bluez version 5.

Pairing process

Login to the affected computer by a wired keyboard or by ssh.

First, make sure the local Bluetooth controller (e.g. a Bluetooth dongle the built in Bluetooth radio) is recognized:

# lsusb

Bus 001 Device 004: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp. LAN9500 Ethernet 10/100 Adapter / SMSC9512/9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

The above output is from a Raspberry-Pi revision 'B' with archlinux-arm and a Keysonic Bluetooth Dongle.

Three items worth remembering:

Bluetooth devices (keyboard) and controllers (dongle) need to be paired once.
The Bluetooth controller needs to be powered up after every boot.
The Bluetooth controller needs to be told to connect to the keyboard after every boot.

Pairing is a one time process, required only once. There are Bluetooth keyboards sold with a Bluetooth dongle which come already paired, but that is not certain. We will use the bluetoothctl command from bluez-utils to pair our dongle and the keyboard.

Power up can be done with bluetoothctl, or automatically in /etc/bluetooth/main.conf, see below.

Same for connecting, either bluetoothctl or hcitool can be used, the latter is more useful for scripting.

We will use bluetoothctl for the pairing process. Run the command to get at the [bluetooth]# prompt.

# bluetoothctl

[bluetooth]#

Note: If you are on a color console: the word "bluetooth" is in the default color as long as no devices are available, and blue as soon as required devices and/or controllers have been found.

While in bluetoothctl power up the controller:

[bluetooth]# power on

Changing power on succeeded
[CHG] Controller 06:05:04:03:02:01 Powered: yes

Next, tell bluetoothctl to look only for keyboards, and make that the default agent:

Next, put your controller (the local dongle) in pairable mode:

[bluetooth]# pairable on

Changing pairable on succeeded

Next, put your keyboard in an active mode, where it is discoverable, i.e. pairable. Some keyboards have a special button for this on the underside, or require a special key combination to be pressed. See the documentation of your keyboard. Please note that this discoverability of a device is time limited; some devices are only visible for 30 seconds, other for 2 minutes. Your mileage may vary.

Next, let the controller scan the Bluetooth frequencies for a suitable device:

After a few seconds the address of the keyboard should be listed as found. This line will repeat over and over, but will not stop you from entering new commands.

Next, actually do the pairing. The address used is the Bluetooth MAC address of the keyboard:

Next, make this a trusted device (this allows the device to establish the connection on itself). Again, the Bluetooth MAC address is the address of the keyboard device:

[bluetooth]# trust 01:02:03:04:05:06

Trusted

Next and finally connect to the device (keyboard). Again, the Bluetooth MAC address is the address of the keyboard device:

Done. Leave the bluetoothctl utility:

[bluetooth]# quit

Now the external device (i.e. keyboard) and the USB Bluetooth dongle are paired permanently, unless you break the pairing intentionally.

Troubleshooting

Bluetooth controller does not show up in

Load generic Bluetooth driver:
Is it an USB adapter or integral to the system? Use for integral adapters

Bluetooth controller is not visible in `bluetoothctl`

Check the unit status.
Check: You run the command with superuser privileges using or . Otherwise you have blue [bluetooth]# prompt and get the following message when powering on the controller:
```
[bluetooth]# power on
No default controller available
```