While you would like to never use a black box in the traditional sense after an airplane accident, they can provide data that can hopefully later be used to diagnose what went wrong. This concept can also be applied to automotive applications to determine driving habits, analyze incidents, or for optimization purposes.
While there are commercial black boxes — or telematics devices — available, you could also build one yourself giving you total control over how this data is recorded and used. “TheForeignMan” did just that, using an Arduino Mega to pull data from his Ford Fiesta’s OBD-II diagnostics port via a Bluetooth adapter. This data is combined with readings from a GPS receiver and saved on an SD card. Data can then be removed and graphed on a map as needed. Interestingly, if you’re worried about running out of memory, you’ll be relieved to know that an 8GB card will last you nearly 50 years if you drive your car two hours per day.
Code for the project is available on GitHub, along with SketchUp Models for the “black box” enclosure itself. While this unit may serve as great material for optimizing your (or your teenager’s) driving habits, the author is quick to note that this may not be valid as evidence in a court of law.