It worked right off the bat!

Congratulations, you have created the first OBD application to connect up & work reliably for the N900 & my standard orange-label ELM-327 bluetooth dongle!

It even shuts off the bluetooth when it closes, so no need to worry about additional power usage! Far more clean & neat than Carman's leaving GPS on, etc.

My notes:
1. I already had my ELM-327 bluetooth dongle entered as a trusted device in the N900.
2. It was necessary to set the N900's bluetooth config to "Visible" in order to connect with the dongle I have.
3. After pyOBD is started, if you go to the OBD menu & click "connect" even if you have connected to a particular BT OBD dongle before, it does not connect. Status remains on "Connecting..." & does not time out or error message.
4. It seems to be necessary at each start to use "Search BT". A status bar with "Searching BT device..." comes up then disappears. After a wait, another status bar comes up with "Found a BT device". This status message will be followed by a configuration screen if the device can be used by pyOBD, otherwise, nothing happens afterwards. The "Found a BT device" status message has even come up in a room with no BT devices in it. It might be useful to display some status message after "Found a BT device" if connection cannot proceed to the configuration screen for whatever reason, so the user will not wonder if he should wait longer, or if the program has hung, etc.
5. After the config screen for the BT device comes up and OK is selected, it does not automatically connect to the BT device. It might be useful to have another button to go directly to "Connect" from the BT device screen to eliminate confusion to the user and increase speed of use.
6. After the "Search BT" routine completes with "Found BT device" and then the BT device config screen finishing with OK, then the "Connect" selection under OBD-II is used. The wait for connection I experienced was about 30 seconds.

Other than a little wrestling with wondering what the BT connection required of me & the N900, and wondering if everything was OK during the waits, it worked great!

Short version to get it going:
1. Pair your BT dongle with the N900 from the N900's BT config screen accessed from the N900's status bar. Set the BT config to "Visible".
2. Start pyOBD
3. Under OBD-II, select "Search BT". Wait up to 30 seconds between events for sequence of: status bar "Searching BT device", status bar "Found BT device", and config screen for found BT device. Click OK on config screen.
4. Under OBD-II, select "Connect", & in about 30 seconds the pyOBD's status will show it is connected.
5. Enjoy the pyOBD readouts of the OBD-II data.

As a strange addition to pyOBD's success, for the first time Carman is semi-reliably connecting & running. Whether it's something pyOBD brought with it, or learning through the less complex pyOBD that the N900's bluetooth config must be set to "Visible", or whatever, Carman is now connecting to this BT OBD-II dongle. Although you have to push Carman's "connect", watch it fail to connect, push connect again, & watch it always connect on the second try.

At any rate, pyOBD is much more useful for diagnostic use with its full complement of data sets from the OBD-II port.

Congratulations, M750!