How to play with Bluetooth under Linux
This is a starter for Bluetooth on Linux. Things are still a little in flux so it may work somewhat differently for you.
Have a program ready on the NXT that sends some data via Bluetooth.
bluez-utils and a recent kernel
with Bluetooth enabled.
(I have Debian with kernel 188.8.131.52 and bluez-utils 3.1 .)
Plug in your Bluetooth dongle (any recent one should do).
Then look at the manpages and play a little with the commands
To receive data from an NXT do the following:
sdptool add --channel=3 SP
This announces the Serial Port service, hence SP.
It may already be done by your system,
you can check with
sdptool browse local.
You may also leave out the --channel option, the default channel is one.
rfcomm listen /dev/rfcomm0 3
This listens on RFCOMM channel three, when the connection is established
/dev/rfcomm0 will be created
and data will arrive there.
On the NXT connect to your host.
A sore point is the entry of the pin on the Linux host,
for me it is in the file
A "line is busy" message on the NXT can mean anything,
e.g. if you forgot one of the commands above.
On another terminal do something like
cat /dev/rfcomm0 | od -t x1 -w1 -v -Ax
start the program on the NXT and watch the data arrive. I had a small program that sent "good job", this is the output I got:
000000 00 000001 80 000002 09 000003 00 000004 09 000005 67 000006 6f 000007 6f 000008 64 000009 20 00000a 6a 00000b 6f 00000c 62 00000d 00 00000e 0a 00000f