Old project and new motivation

While I have kept myself busy (i.e. David Webber wrote quite a few books, especially on Honor Harrington. Well so did Elithabeth Moon and Tanya Huff...), with the highway-robbery gas pricess (pun and all) I have been trying to find if my car is using too much.

So after some obvious culprits checks and replacements, I seem to have come to the conclusion of needing to connect to the car computer. Or but an ODBII reader.

A little bit of tangent here. ODB seems like a rats nest of standards and updates. Wikipedia contains decent summary. One thing I took away form the research was the use of CAN in the new cars. Now this mysteriously useless network protocol has stumped me previously in other PIC (microchip) datasheets. But apparently, I have bought several PICs with CAN support already for the airplane. (I am worried if the protocol versions match; will find out eventually)

Long story short, seems like I need to get back and build that RC controller and leave two extra cables for CAN. Since the computer connection (UART or USB) is expected, had I had the RC controller, I wouldn't have to get any OBD readers.

The redesign is not surprisingly easier the second time around. Though now I am stuck with older parts and datasheets seem harder to find. (LCD datasheet has evaporated.) Also, the buck converter seems just as involved. Currently feel very tempted to just connect the 3.3 V regulator I have come by. And forgot how batteries get charged... Redesigning the Power circuit is no fun.

Maybe I am being to demanding, but for now am trying to build a power circuit that:

• Detects low batteries (LVDIN in PIC seems useful)
• Uses external power, if available
  
• Recharges the battery if external source available

In fact, I will postpone this till later revision, will just stick to a regulator and recharge more often.

Great, now can go back to the more interesting XBEE and dsPIC30F3014.