Dale, That's a cute idea, first means of doing it that comes to me involves a so-called bridge rectifier directly off the battery with a single seperate diode that would feed a voltage to some pin in one direction and not the other. Only problem with this scheme is the rectifiers cause you to "lose" a volt and a half of supply voltage. There may be a more modern voltage regulator of the switching type that does a better job.
clever design. Tom Fowle
