Thread: [Android Development] Can OBDSim help me ?

A generator is something that creates data for you. You basically want the Random generator, or Cycle generator with a cycle time of say, 30. Cycle would make the number steadily go up, and roll over its max value every 30 seconds (So go from 0-255mph in 30 seconds). This would give you a good basis for starting.

The command line for that would be "obdsim.exe -g Cycle -s 30". In the case of the Cycle generator, the seed number is how many seconds per cycle you want.

Ok thanks, I understand now.

As you said, I'm using :

Code:

cidou@cidou-Inspiron-9300:~$ obdsim -g Cycle -s 30
Setting cycle length to 30 seconds
SimPort name: /dev/pts/1
Successfully initialised obdsim, entering main loop
10.000029 seconds. 0 samples, 0 queries. 0.00 s/s, 0.00 q/s
10.000102 seconds. 0 samples, 0 queries. 0.00 s/s, 0.00 q/s
10.000786 seconds. 0 samples, 0 queries. 0.00 s/s, 0.00 q/s

About the data results, it seems obdsim is now looking for queries, right ?

If I want obdsim to generate some speed datas for me, do I need to send the appropriate command (like i will do on the ELM327) ?

If I correctly understand the OBD-II PIDs ( http://en.wikipedia.org/wiki/OBD-II_PIDs ), I'll have to send 010D to get speed datas :

Code:

Mode
(hex)	PID
(hex)	Data bytes returned	Description	Min value	Max value	Units	Formula
01	0D	1	Vehicle speed	0	255	km/h	A

But now, how can I communicate with obdsim ? Is it possible just with an other terminal ?

You write data to the port that obdsim has opened up for you. In your example:

Code:

SimPort name: /dev/pts/1

Now there's a virtual serial port sitting at /dev/pts/1 and you can read/write to it using your application as if you were connected to an ECU through an ELM327 cable.

Fundamentally you need some way to communicate between OBDsim and your software on the android device. By default, obdsim creates a pty on the local machine. So, you could run obdsim on the device itself and tell your software to read from the pty.

That might be a PITA; what you probably want is bluetooth, with obdsim running on your main machine. OBDSim supports bluetooth just fine so long as you build in support [when you build it, you need libbluetooth-dev or similar available on your system]. Also the man page gives the example commands to make it available correctly from the main machine

Each "generator" is a different way to generate data; you're right, that "010D" will grab vehicle speed; the question is, when obdsim turns up a number, where will that number come from? Different generators create numbers different ways; random makes up a number every time you ask for one, gui_fltk pulls one from the gui, etc. The "seed" is simply a parameter to the generator, different generators use the seed for different things.

So, for a quick and easy first go; leave out the generator and seed, and just run "obdsim -c" at the command-line; that connects screen to it so you can experimentally try communicating with an ELM327 device by hand. [so you can, for example, type '010D' and see the results]. Assuming that's all copacetic, to do your actual development you'll want "obdsim -b", which simply tells obdsim to run as a bluetooth device.

In the longer run, most folks find it best to have sensible data coming out of the sim. That's what the 'Logger' plugin is for; run with the 'Logger' generator and a seed that points to a database you either create yourself, or download from here:
http://icculus.org/obdgpslogger/examples/ces2010/ [me driving my mini to vegas]
http://icculus.org/obdgpslogger/examples/striple/ [me pottering around in the santa monica hills on my putt putt]

Gary (-;

And, of course, to answer the original question: Yes, OBDSim can help you :-)

Gary (-;

thanks for your answers, i'm using bluetooth and it works really great!

is there a list of obdsim supported commands like speed, engine rpm, ... ?

Short version: no, that's what 0100, 0120, 0140, etc are for

Long version: It's up to the individual generators which PIDs they support. Logger, for example, reports a list of the PIDs available in the database it's using.
This database has one set of PIDs: http://icculus.org/obdgpslogger/exam...treettriple.db
This has completely another: http://icculus.org/obdgpslogger/exam...010/ces2010.db

The right thing to do is have your code always use 0100 first, to get a list of supported PIDs from the vehicle/sim, and then decide what to do from there.

Gary (-;

Hey all,

i'm also trying to develope an android app to read OBD2 data.
I've downloaded and builded the obdgpslogger for linux und i'm using obdsim to generate data.
Everything works just fine, but Bluetooth

I tried to connect with other OBD2 read apps like torque oder OBDII Reader, but it didn't work.
And i've to tell you that i'm not a experienced linux user
I tried the following:

first i binded my Android Phone to rfcomm (i hope i have to take the phones bluetooth adress here? But i also tried the one from my laptop)

Code:

sudo rfcomm bind 0 7C:61:93:D2:0C:BA 1
sudo sdptool add SP

where 7C:61:93: D2:0C:BA is the bluetooth adress from my android phone. So i get a rfcomm0 in /dev
next, i tryed to start

Code:

obdsim -b

which was starting but with an unknow Simport name

Code:

obdsim -b
SimPort name: Unknown
Successfully initialised obdsim, entering main loop

why?
So i tried to tell the rfcomm device at startup

Code:

obdsim -b -t rfcomm0
SimPort name: Unknown
Successfully initialised obdsim, entering main loop

unfortunately with the same result. Unknown SimPort name.
Also tried to connect to the device with rfcomm and so on..
Everytime i try to send a OBD command to my laptop there is a report that my device [,,] tried to acess the service »00001103-0000-1000-8000-00805F9B34FB«.
So there is an incoming signal, but i do not know how to send this to the simulator.

What i'm doing wrong? Or do i have some errors in reasoning and this is not possible?

Thanks in advance!

The simport name will always be unknown when you first open the bluetooth simport. I don't remember what it becomes when it's not unknown, but it's not on startup

The mistake you made is almost certainly the bind; you need to bind to the mac address of your bluetooth chip in the PC that obdsim is running on, not to your phone. I think the way to go is:
1) First, reboot. Bluetooth seems to carry all kinds of weird state with it, even when you unplug&replug the bluetooth card. Of course, this is linux so it's probably not strictly necessary, but I don't know which modules need to be reloaded for it to do the right thing.
2) Run those commands to make your PC advertise it can do serial correctly
3) Pair your phone to your pc
4) Run obdsim -b.
5) Stick it in the camel and go.

Sorry if that's a bit arcane... linux bluetooth sometimes seems that way, although it's definitely less arcane than the windows equivalent :-)

Gary (-;