Originally Posted by
corrado33
The problem with automatic on/off is that there is no easy way to do it. It'd either require GPS or a wheel sensor. Sure, you could probably get away with an accelerometer, but technically if you're an extremely smooth rider you could trick it into thinking you're stopped when you are actually moving. (I doubt someone could achieve this.) There is no force when you're moving at a constant velocity, so the accelerometer would output nothing in that instance.
Velodroom is a light that does have accelerometers in it for auto on/off, but I doubt it'd be cheap and it looks like it's only currently a taillight.
Cateye use a light sensor and accelerometer on there "auto" lights, not especially expensive, lights are always on when its dark and you're moving. Its sensitive enough that it won't turn off when you're stopped relatively motionless at a stop light.
These aren't daytime bright though.
TL-LD570-R | CATEYE