Automatic vehicle lighting switching for low visibility - has photosensitive resistors responsive to light from several defined directions

摘要

The device is used to turn on vehicle lights automatically if the external ambient light conditions fall below a set level. The device contains several, at least three, photosensitive resistors (1). These are arranged in recesses (2) pointing in different directions, and having openings such that light can only enter over a defined, limited, angle (3). The device is typically mounted just inside the front windscreen. The arrangement ensures that, under normal daylight conditions, switch on does not occur if the light to some of the cells is obscured. Similarly, after automatic switch on, if some cells are illuminated, for example by the light of an oncoming vehicle, there is no turn off. A tell-tale lamp (4) may be fitted to warn the driver that the lighting has been turned on automatically.