From: "Gus Salavatore Calabrese" Sent: Wednesday, August 31, 2005 8:00 AM > I have been designing a vehicle tail light which would start flashing > at a slow rate > as the brakes were applied and at a faster rate as the brakes were > applied harder. > Ideally this unit would be standalone except for power ( which might > be solar provided ). > > I see no way to differentiate between braking and going downhill. Any > ideas ? Do you mean you want to use some sort of accelerometer to measure breaking? According to our modern understanding of physics there is no difference between acceleration and gravity. If you are in a box with no windows and no way to see what's going on outside the box, there is no possible instrument that could be built to tell you if you're tipping forwards or accelerating backwards (slowing down if you're moving forwards). Jason -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist