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Automatic OBD Logger Pausing

Automatic OBD Logger Pausing is a feature that enables the AutoPi device to automatically pause any OBD loggers when it detects that the vehicle has stopped shaking (which also likely means that the vehicle has stopped moving). This feature is useful in situations where the vehicle that the AutoPi is plugged into has a CAN bus protection. Such vehicles usually detect CAN bus traffic when the vehicle is locked and in turn trigger the alarm of the vehicle - this is done to try and protect the vehicle from being fiddled with externally through the CAN bus. Examples of such vehicles are the BMW i3, some Mini Coopers and some Porche models.


In fact, not only the loggers are being paused, but in general the device is not allowed to send any CAN frames on the CAN bus of the vehicle. This means that if you attempt to manually send a CAN frame with a command such as obd.send or obd.query you will receive an error.

Passively listening (also known as sniffing) on the CAN bus is still allowed though.

How does it work?#

The Automatic OBD Logger Pausing feature works by using the data from the accelerometer integrated into the AutoPi. The accelerometer will detect motion and trigger events based on the motion detected. The three events that are being triggered are:

  • vehicle/motion/steady
  • vehicle/motion/shaking
  • vehicle/motion/jolting

Using these events (and the vehicle/motor or vehicle/engine events as helpers), the AutoPi is able to determine when it's a good time to pause and unpause the loggers to avoid setting off the alarm of the vehicle.


Keep in mind that the vehicle/motion/jolting event is not used to determine the behavior of the Automatic OBD Logger Pausing feature.

How to set it up?#

To enable the Automatic OBD Logger Pausing functionality, you will need to ensure the following advanced settings are set on your device:

  • OBD > Automatic Logger Pausing must be set to True (Enabled)
  • Accelerometer > Motion Events > Enabled must be set to True (Enabled)

You can confirm that the setup has been made successfully if you confirm the following two changes in your device's services:

  1. Navigate to the workers of the Accelerometer Manager (Services > acc_manager > Workers) - there you should see an xyz_logger worker. If you open it up, you should be able to see that the trigger in the Workflow is motion_event - this enables the vehicle/motion/* events.
  2. Navigate to the reactors of the Event Reactor (Services > event_reactor > Reactors) - there you should see two new reactors - enable_obd_on_motion_shaking and disable_obd_on_motion_steady_or_trip_end - these reactors are responsible for enabling and disabling the OBD logging.


Sometimes, you might notice that even though you have enabled the Automatic OBD Logger Pausing feature, the AutoPi is still sending CAN Frames on the CAN bus. This is usually caused by your vehicle being too easy to shake which in turn triggers a vehicle/motion/shaking event much more easily (this is the event that reactivates the OBD loggers). Depending on the vehicle type that you are using, the driving behavior, road conditions and more the device might think that the vehicle is being driven while in fact it isn't or vice versa.

For this reason, we have made it possible for you to change and fine-tune the way that those motion events are being triggered. You can find the fine-tuning settings in the advanced settings of your device under Accelerometer > Motion Events. We suggest that you focus primarily on the Debounce Delay and Shake settings, because the vehicle/motion/jolting event is not used to reactivate the OBD loggers - only the vehicle/motion/shaking event is.