Data with ignition off

[nawaz]

I have been experimenting with the data logger for the last few days.

It seems that the logger continues to log PID data when the vehicle is switched off and I end up with a huge file. It might be vehicle dependent but it seems that even with ignition off the ECU in my vehicle keeps responding to requests on the OBD port. I can probably check that the vehicle is switched off by looking at engine rpm over few minutes and then putting the protocol processor to sleep. However, I am not sure how to detect that the vehicle is switched back on for another journey, wake up the protocol processor and start logging again?

Any thoughts?

[stanley]

Your car's ECU might be still reponding to PID request even if iginition is off. This is not the case for most cars and this causes the logger to continue logging data. You can tweak the code by adding a check for RPM and let the logger stop logging.

[nawaz]

Yes stopping is relatively easy. But is there is a way to know that the vehicle has started up again in this case?

[stanley]

Just check RPM regularly.