blog entry #3
This update shows the Car Cape running on a Beaglebone Black.
Both vehicle simulator and vehicle recorder systems have been built and they communicate with each other fine over the CAN bus.
We are still having a devil of a time sorting out OBDII communications with a real vehicle. This is the main reason for such a long delay since our last posting, however I figured we need to post at least an update.
So far there are 6 screens to display sensor data from the sensors on the Car Cape.
We have not spent much time on these as the OBDII interface has been taking so much time.
Here are some screen shots to give some idea of what they look like:
This screen shows location coordinates when the GPS finds enough satellites. Right now it is still showing UTC time.
This is a little warm because I have some bright lights shining directly on the module.
We are still sorting out some of the analog channels...
The LCD updates "instantly" in response to the keypad scroll buttons because it is interfaced via SPI.
The following video demonstrates how quickly the LCD repaints after each scroll button push:
Here is a picture showing the OBDII breakout module connected to the Vehicle Simulator/Recorder module:
Here is a picture showing the card stack making up the vehicle simulator/recorder module:
Right now we are analyzing commercial OBDII readers like the one shown above to determine how to handle vehicle communications properly.
We have started using one of these CAN bus interfaces to help analyze what is going on with the CAN / OBD2 bus:
This module is helping significantly at this stage to get us over an impasse.
The 2 BBB modules communicate with each other.
The 2 BBBs can communicate fine with the USB-CAN module above.
The commercial reader can also communicate fine with the USB-CAN module.
The commercial reader does not communicate with either BBB.
It seems they somehow think the frames are invalid.
Unfortunately my software partner is away for a month starting today, and the rig is at his place, so further updates will be delayed for a month.