Bluetooth daemon
In the default installation a daemon (bluetoothd) runs in the background (run from the file /etc/init.d/bluetooth). This daemon takes care on recognizing and connecting to known bluetooth devices and may be cofigured with configuration files in /etc/bluetooth. For autoconneting a headset the following line in audio.conf should be uncommented (remove #):
AutoConnect=true
To restart the daemon type sudo /etc/init.d/bluetooth restart.
Remark: Using the command line tool sudo hcitool cc <MAC-Adress> did not lead to a stable connection to a known device in the test environment here when the daemon was running.
DBus
In order to connect a disconnected but physically present and paired headset we can use D-Bus from a script. Here's an example in python:
#!/usr/bin/python
# Toggles headset connection
import dbus
from dbus.mainloop.glib import DBusGMainLoop
dbus_loop = DBusGMainLoop()
bus = dbus.SystemBus(mainloop=dbus_loop)
#Get dbus interface for headset
manager = bus.get_object('org.bluez', '/')
iface_m = dbus.Interface(manager, 'org.bluez.Manager')
adapterPath = iface_m.DefaultAdapter()
adapter = bus.get_object('org.bluez', adapterPath)
iface_a = dbus.Interface(adapter, 'org.bluez.Adapter')
devicePath = iface_a.ListDevices()[0] # assuming first device
device = bus.get_object('org.bluez', devicePath)
iface_h = dbus.Interface(device, 'org.bluez.Headset')
#Check state of connection
connected = iface_h.IsConnected()
print 'Toggling connection. Please wait'
# toggle connection
if not connected:
try:
iface_h.Connect()
print 'Connecting: ', devicePath
except:
print 'Device not found'
else:
iface_h.Disconnect()
print 'Disconnecting: ', devicePath
In case we have more than one Bluetooth device we will have to adapt the devicePath appropriately, of course. The example above will connect a Headset. Change the interface to a different protocol for any other service (e.g. AudioSink).
Pulseaudio
If you know the MAC adress of your Bluetooth device you can connect it as an output sink for pulseaudio by:
pacmd set-default-sink bluez_sink.xx_xx_xx_xx_xx_xx
Where xx_xx_xx_xx_xx_xx is the MAC address (replace ':' by '_' for pulseaudio to recognize it).
See also this answer for more details.
Best Answer
If you are using ALSA, amixer can be helpful for your script programming.
When dropping the
amixer --helpcommand in a terminal you will see something like this:Depending on your soundcard, levels may be different than mine, but you can use
alsamixerin the terminal in order to check which levels and which features in your sound card you can call in a command to set the volume as you wish.In my example, with my principal sound card (I have 2: the embedded and a PCI audio card), levels are from 0 to 100, this way I can change the volume of a desired input/output in my soundcard by dropping in a terminal the next command:
In the first command, the result will set the Front panel output to 78% level and the second one will set the Front panel output to 100% level.
In order to gather information related to your mixer controls, drop the
amixercommand with no parameters and you will get a list. Or indicate which audio device you wish to see a list of controls withamixer -c X(where "X" is the number of your audio device).BTW: Remember that DB values are calculated logarithmically and not linearly.