Updated code here:
https://create.arduino.cc/editor/tfabris/4c5eea9a-1462-45d7-908d-81a5bb6b0d90/preview

Changes in this version:
- Additional code comment cleanup, fixing typos, clarifying new Hijack information such as V522 and suppress_notify=2, add the new voltage divider circuit description, etc.
- New section in the code comments about possible special needs for powering the empeg car with this configuration (should probably read it).
- New section in the code comments about special needs for connecting the Arduino debug cable and startup order when debugging (you'll need these tips soon).
- A couple new functions to handle situations where the bluetooth chip gets reset - attempting to work around some behavioral bugs I encountered surrounding disconnect/reconnect situations.