Once set with the location of the driver's eyes the system would interpose a relatively small sun blocker between the sun and the eyes. The position of the sun could be detected by a relatively simple electro-optical device. A computer would then derive the position required for the sun blocker and move it as required. This could be done using geometry or it could be done by having perhaps a thousand possible positions of the sun and twenty or so positions for the driver's eyes allowing a table lookup for each sun block position..-- hangingchad, Nov 09 2004 Someone posted this before http://www.halfbakery.com/idea/Sun_20SpotBut, as waugsqueke notes on this related idea, it seems to have gone away. [DrCurry, Nov 09 2004] They're always looking for interesting ideas to brainstorm... http://www.irvinaut...ve.com/products.htm [RayfordSteele, Nov 12 2004] I *almost* questioned the need for this idea, before I remembered where I was. Phew, that was a close one [+].-- DocBrown, Nov 09 2004 Interesting. In one of my former lives I was a sunvisor engineer at the following link.-- RayfordSteele, Nov 12 2004 [tahuyahick] I suppose the sun-sensor could be used to "see" oncoming headlights. On the other hand, there is such a magnatude of difference in brightness between sunlight and a headlight that two different detectors might have to be used. There was some kind of "magic-eye" headlight dimmer accessory on the market some years back. I never had one and I haven't seen it advertised in years.-- hangingchad, Nov 13 2004 random, halfbakery