======
NXT and BlueTooth on Linux
======

Most of this is obsolete unless you still run a really old distribution.
Just check that a Bluetooth handler is running and things should be
working by themselves.....


If you still need it this is the Intro written for the initial version
-------------------------------

All of this is tested on a Linux Fedora Core 4 installation
with this RPM loaded (see at the end for Fedor 6 and later)

bluez-hcidump-1.18-1
bluez-utils-2.15-7
bluez-pin-0.24-2
bluez-libs-devel-2.15-1
bluez-libs-2.15-1

To use a BlueTooth USB dongle to communicate with NXT.

As Root:

1) if bluetooth services are not on ("service bluetooth status" will
    tell you)
    #service bluetooth start

2) attach dongle (wait a few seconds to allow configuration by the OS)

3) check dongle
  #hciconfig
     hci0:   Type: USB
        BD Address: 00:30:91:40:0D:44 ACL MTU: 192:8 SCO MTU: 64:8
        UP RUNNING PSCAN ISCAN
        RX bytes:101 acl:0 sco:0 events:13 errors:0
        TX bytes:300 acl:0 sco:0 commands:13 errors:0
or for a more complete description 
  # hciconfig -a
      hci0:   Type: USB
         BD Address: 00:30:91:40:0D:44 ACL MTU: 192:8 SCO MTU: 64:8
         UP RUNNING PSCAN ISCAN
         RX bytes:101 acl:0 sco:0 events:13 errors:0
         TX bytes:300 acl:0 sco:0 commands:13 errors:0
         Features: 0xff 0xff 0x8f 0xf8 0x18 0x18 0x00 0x80
         Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3
         Link policy: RSWITCH HOLD SNIFF PARK
         Link mode: SLAVE ACCEPT
         Name: 'gip.fi.isc.cnr.it-0'
         Class: 0x120104
         Service Classes: Networking
         Device Class: Computer, Desktop workstation
         HCI Ver: 1.2 (0x2) HCI Rev: 0x639 LMP Ver: 1.2 (0x2) LMP Subver: 0x639
         Manufacturer: Cambridge Silicon Radio (10)


4) start BT on the client (e.g. switch on the NXT)

5) scan
  #hcitool scan
   Scanning ...
         00:16:53:00:60:55     NXT

6)[It seems this is not necessary but I found this in some places]
   You nedd to define your device in 
     /etc/bluetooth/rfcomm.conf 
-----------------
  rfcomm0 {
        # Automatically bind the device at startup
        #bind no;
        bind yes;
        # Bluetooth address of the device
        device   00:16:53:00:50:55;
        # RFCOMM channel for the connection
        channel 0;
        # Description of the connection (The same as the device NAME)
        comment "NXT";
  }
-----------------
or use rfcomm bind <dev> <bt_addr> [chan]
     #rfcomm bind rfcomm0  00:16:53:00:50:55 1

You can check it with
     #rfcomm
       rfcomm0: 00:16:53:00:50:55 channel 1 clean    

7) [Again. It seems this is not necessary]
 register service (SP=Serial Port) 
      #sdptool add --channel=1 SP
   check with sdptool browse local
   ........
    Service Name: Serial Port
    Service RecHandle: 0x10001
    Service Class ID List:
      "Serial Port" (0x1101)
    Protocol Descriptor List:
      "L2CAP" (0x0100)
      "RFCOMM" (0x0003)
        Channel: 1
    Profile Descriptor List:
      "Serial Port" (0x1101)
        Version: 0x0100


8) first time you connect to a device you need to exchange PIN
   but the default setting doesn't seem to work(at least on FC4).

   - in  /etc/bluetooth/hcid.conf  you need the lines 
       security auto;
       pin_helper /usr/bin/bluepin;
   - if the /usr/bin/bluepin (or bluez-pin) that comes with bluez
     doesn't work substitute it (can have a different name as long as it
     the same in hcid.conf) with an executable file with the lines
     --------------
       VAR=`cat /etc/bluetooth/pin` 
       echo PIN:$VAR 
     -------------
   - put a PIN code in /etc/bluetooth/pin (e.g. 1234, the default for
     NXT)

   - connect and give the same PIN from the device.

   - the connection keys will be saved in /etc/bluetooth/link_key

   As /etc/bluetooth/pin is mode 0600 and /etc/bluetooth is writable by
   root only, this first connection has to be made as root. After the
   link file is written anyone can connect to that BT device  


Debug) [optional] Start Dump on BT port
     # hcidump -X -V 
   use CTRL-C to stop it. The hcidump manual will tell you all about it
   and the options you can use to see what's going on when two BT
   communicate.
 

As User:

Use NXTRC to interact with the brick or write a program that does......

=============================================
A note about Fedora Core 6 and later

Under FC6 and  later everything changed. Both bluepin and bluez-pin are gone and
have been replaced by "bluetooth-applet" that does all the work. You have to
be sure it's running before attempting to connect to the NXT for the first
time for the PIN exchange; after the first time the devices are coupled and
you can do without it.  From what I have seen it's started by default by Gnome
but not by KDE so remember to start it by hand. Another applet you can use is
kbluetooth, made for KDE, I suppose.

The RPM loaded are:
bluez-libs
bluez-gnome 
bluez-libs-devel
bluez-utils
kdebluetooth