You might recall that the new Saab 9-3 has directional headlamps. I heard that and thought “cool, they turn around corners”. There’s a little more to it than that, though. Here’s a quick look. There’s a million more pictures I could post on this, but I think these ones will be sufficient to ‘enlighten you’ (he he he)
As first imagined, the lights do indeed turn based on the direction and speed of the car. If you’re rounding a bend, the outside headlamp (depending on which way the bend runs) will turn half as much as the inside one. So if you’re in a right-hander like in the image below, the right headlamp will turn as much as 15 degrees whilst the left headlamp will turn a maximum of 7.5 degrees. This widens the field of illumination and gets you through the bend a little clearer.
Not only do they turn left and right, they’ll go up and down as well. Not much new there. These will, however, adjust up and down automatically depending on your speed. If you’re doing more than 110 km/h the headlamps will rise a little to give you an increased field of illumination in front. They’ll dip back down again when you reach 100 km/h
Further to all that, if you’re travelling to a country where they drive on the
wrong other side of the road, the lamps can be adjusted via your SID so that they won’t dazzle drivers on the other side of the road in your destination country.
So how does all this work? A bunch of computers and sensors control the whole shebang. These sensors read your car’s speed, gearing, and degree of turn. This is all processed and fed into the little motors that move the headlamps around. The simple diagram looks like the one below. The complex one involves I-Bus’ and P-Bus’ and really isn’t as descriptive.
Great technology, though if you’re like me you have a little voice in the back of your head saying “here’s another thing that might go wrong”.