[jrocket567]

So you're more or less trying to see if you can get the robot to tell if it is upside down or right side up, or anywhere in between-- Ok- here comes a mechanical brain idea, so it might make absolutely no sense at all- Take a weight (hunk of lead), and suspend it from a potentiometer or some other device that can measure angles. When the robot changes its attitude relative to the ground (gravity), the weight will still hang perpendicular to the ground. The potentiometer or other device can measure the angle that the weight is hanging relative to where the weight hung when the robot was parallel to the ground. You will always know what way is down-- the weight will always point that way. Make any sense at all??