Henry Baker <hbaker1@pipeline.com> wrote:

I'm surprised that auto LED headlights don't already broadcast their vehicle VIN# (maybe they do?).

I don't know, but many of them do rapidly flash on and off. So do LED taillights.

Apparently, one of the countries in the Middle East is now requiring some sort of RFID IFF for automobiles. Sure makes the CIA drone program a lot more accurate...

RFID doesn't work over long distances. I'd worry more about RFID tags in US passports, which make it possible to build a IED that will detonate only when a US citizen is in range.

I seem to recall that someone at MIT had developed an LED display for bicycle spokes that was time-multiplexed in such a way as to provide a full circular bit-mapped display -- kinda like those WWII radar displays.

Synchronized clock displays, and the like, on things like spinning fan blades can be found in any novelty shop. But I think that would be a bad idea on bicycle wheels, since cyclists don't want motorists to be the least bit confused as to what they are seeing. Speaking of which, traditional headlights are a very bad way to illuminate your path, as they make it difficult for other road users to see anything except your headlights. Car headlights are designed to only light what's directly in front or below, so as to not shine directly in the eyes of motorists, cyclists, or pedestrians. And maybe that works well on perfectly flat terrain, but it doesn't work well anywhere else. Gyroscopically stabilizing them wouldn't help, since other road users follow the terrain. Decades ago, Edwin Land proposed that all headlights and all windshields be diagonally polarized. Pedestrians and cyclists could wear diagonally polarized glasses. You'd see the reflected light from your own headlights, but you wouldn't be dazzled by oncoming headlights as you are now. Since polarizers aren't perfect, you could still *see* the oncoming headlights, but they'd no longer be blindingly bright. The disadvantage is that all lights would have to be twice as bright to compensate. Anyhow, it never caught on, and is unlikely to at this late date. Today's technology gives more options. I suggest that car headlights use something like Google's face-detection algorithm to keep bright light out of everyone's eyes. Some light would be sent toward eyes, but not enough to keep people from seeing anything else. Bike headlights, at least in brightly lit urban and suburban areas, are mostly for being seen rather than for seeing. The same algorithm could be used in reverse for them, aiming all their much dimmer light toward eyes. That would greatly increase the battery life, assuming the computer chips don't use more power than the lights. The light could also be directed toward anything dangerous that the cyclist might not have noticed, such as a fallen branch across the road.