Thread: Cannot initialize DBUS obdsim generator

That seed [bitofcoast.db] is most useful with the "Logger" generator. I also suggest using a more up to date logfile [at least while trying out sim, using "Logger" just to see *something* work], that's the first one I ever published.

A sample config for the dbus generator is in src/sim/generators/dbus/dbustest.simconf

I am trying to receive random DBUS messages

OBDSim doesn't generate messages, it only listens for signals. If you are writing something that listens for dbus signals, obdgpslogger signals stuff.

Gary (-;

OK, I may be doing something wrong here...

I entered the following command:

Code:

obdsim -s dbustest.simconf -g DBus -o

and I got some encouraging "DBus Config" output. But right after the pty slave name was defined (/dev/pts/1 in case it makes any difference), the following message came up:

Code:

First argument isn't of type int

Everything looked pretty much OK after that, except that every value came out as 0.000000 (temp, rpm, vss, maf, and throttlepos), and dbus-monitor never triggered a signal.

Am I missing something here? Thanks in advance...

OK, the way that obdsim's dbus plugin works is that it listens for signals on the path/member/interface 3-tuple. The source is in src/sim/generators/dbus/gen_dbus.c and should be pretty palatable. From the top:

Code:

/// Mappings and most-recently-seen values are stored in this list
/** DBus messages are expected to come as two numbers; an integer then
   an integer or floating point number. The first is mapped onto a PID
   using this table. The second is the actual value to be passed.
*/

So, what happens is signals are INT32 then INT32 or DOUBLE. The first INT32 is mapped to a PID using "map" entries in the config file. The second is the value. The actual handling is done in dbus_simgen_msgfilter, lines 287 to 317.

The signals are processed as they're seen, and the most recently value is always remembered. When the OBDII tool talking to OBDSIM requests a value, it responds with the most recently seen version [line 261].

The error you saw, "First argument isn't of type int", is because it read the signal you configured, but the first value in the signal was a type other than DBUS_TYPE_INT32

Hope that's helpful,
Gary (-;

Thanks for the extra information. I guess I need to look more into C programming.

I tried figuring out how to send tuples through the command line, but I wasn't able to get it to work. My coding background deals with ActionScript, which I guess is similar to C in a few respects. Tuples look a lot like AS objects, which are sent in key/value pairs like so:

Code:

var tuple:Object = {key1:'key', value1:'value'};
sendDbusMessage(tuple);

Am I on the right track here? A sample command would be really helpful! Thanks again

If you're trying to do stuff using actionscript, sorry, I've never used it at all.

To signal tuples using C, check src/logger/obddbus.c. That code sends UINT32, DOUBLE, STRING, STRING. So change it so it sends INT32, DOUBLE and you'll be set.

Gary (-;

Yeah I'm trying to get the UI done in Adobe AIR. But I meant that I'd like to see a CLI sample... Something like:

Code:

$ obdsim -s dbustest.simconf -g DBus -o

Where should the tuple be placed above, and in what format? Basically I want the AIR app to send shell commands behind the scenes. I could send something like the code above, or using dbus-send, whichever is best. TIA

Can you post your .simconf file?

Gary (-;

Sure. I haven't modified it at all however:

# obdsim dbus plugin sample config file
#
# This sample works with fbd based signals from Fusion Brain devices
# Originally written by cgalpin on the mp3car forums
#
# fbd is a Linux daemon that listens talks to fusion brain devices. It's
# available here:
# http://www.mp3car.com/vbulletin/fusi...ram-linux.html
#
# We specifically listen to only one member from one path from
# one interface

# The message for the member-path-interface 3-tuple must come in as two
# numbers. The first is mapped to a PID using this file. The second
# is a real or integer that is the actual value.

# bus can be "session" or "system"
bus=system

interface=org.openice.fbd.fusionbrain

path=/org/openice/fbd

member=AnalogValueChanged

# Some sample mappings.
# Each mapping is of the form:
# map {decimal FB analog input} -> {hex PID}
# Where 0 >= {analog input} < 13
# and PID is the OBDII service command

# Map engine temperature
map 1 -> 0x05

# Map airflow mass
map 2 -> 0x10

# Map rpm
map 3 -> 0x0C

# Map vss
map 11 -> 0x0D

# Map throttlepos
map 12 -> 0x11

perhaps this will work:

Code:

dbus-send --system \
 --dest=org.openice.fbd.fusionbrain \
 --type=signal \
 /org/openice/fbd \
 AnalogValueChanged \
 int32:11 \
 int32:2600

I haven't actually tried this, mind. From the config above, it should tell obdsim that the rpms are now 2600.

Gary (-;