Okay I’ve been playing using the AutoPi in an MG HS PHEV and have started by setting up a few basic OBD PIDS.
The first problem is that RPM is meaningless for deciding whether the Vehicle is active, however I have found a BMS Status which has various states, the interesting ones are Running and Charging.
I have a log event for the BMS_STATUS, I have yet to see if it logs correctly, but it should. What I need to do is go to sleep within a few seconds of the status not been “3” (i.e. not running), can anyone advise how I can do this. This leads to a second problem, which is that when the car finishes charging, for whatever reason the 12v battery appears to get a charge, or atleast the voltage goes up enough to wake the AutoPi, and trigger the alarm. Is it possible to wake up on something other than voltage.
And finally is it possible to test certain PIDs when the unit is sleeping, my reason is that if unit is awake, and the vehicle is locked, the alarm triggers, however I want to monitor the state of charge, and obviously charging is normally done with the vehicle locked.
When it comes to electric vehicles, the AutoPi isn’t able to get the RPM PID, as usually manufacturers of electric vehicles use their specific PID values. However, if you are able to find out what PID is used to keep track of the RPM for your vehicle, you can use that to keep track of the vehicle’s state.
To get the device to go to sleep faster, what you need to do is to go to the Advanced > Settings > Power page. There you’ll find a bunch of power related settings, some of which will talk about sleep timers. The fields that you’re looking for are the “Period” and “Delay” fields. The “Period” field will decide how long it takes for the device to start the sleep process, while the “Delay” field will decide how long the sleep process will take. If you bump those down to the minimum, you should get the result you’re looking for.
I believe that the reason your alarm get’s triggered is because of communication with the OBD-II port. If that is the case, any type of PID request will trigger the alarm. However, it’s not possible for the device to test PIDs while it’s asleep. The device needs to be awake in order to send those PIDs to the CAN bus.
Thanks Nikola, I’ve knocked the 2 fields down as recommend, to see how that responds.
I have heard a rumour that on the MGs the alarm triggers, when a call is made to the BCM. Can you tell me if I don’t log any BCM events, whether the AutoPI will be polling anything for it’s own use, or wether it just does requests that we manually add.
Been a Phev there are 2 RPM values, and it is quite possible to have vehicle “On” but neither motor spinning, however I have found the Odometer only responds when the vehicle is “On”, so I’m currently investigating that option.
The AutoPi will poll the OBD-II for CAN bus related messages only. Any loggers that you have set up (Car Explorer > Loggers) will be executed within the interval that they have been set up with. Other than that, the device will monitor the voltage that is provided by the OBD-II port, however that is not sending any requests on the CAN bus, it is simply monitoring voltage on the STN chip (which is also used to wake the device up when it is asleep - when the voltage raises above a specified threshold, the device is woken up).
I understand, if the RPM values don’t make sense for your use case, you should definitely go with setting up the Odometer.