Automatic automobile light control system

#The invention relates to an improved circuit for automatically turning the lights of a motor vehicle on and off in accordance with ambient light levels and to turn the lights and windshield wipers on during showers. Also, if the car is provided with power windows and a convertible roof, the windows and roof can be raised.

#Many different arrangements have been proposed in the past for automatically controlling various items on a motor vehicle, particularly the head lights. Often a driver who is driving early in the morning will forget to turn his lights off after dawn and occasionally will leave the lights on after leaving the vehicle, thus discharging the battery. Similarly, drivers often forget to turn their lights on properly at dusk or during a rain shower.

#The U.S. Pat. Nos. to Lohr et al, 2,944,188, Schick, 3,319,116, and Ubukata 3,283,161, describe representative automatic light control systems for automobiles of the prior art.

#FIG. 1 shows a block diagram of the unique system and circuit of the preferred embodiment of this invention.

#FIG. 2 shows a preferred embodiment of a detailed schematic of the circuitry of FIG. 1.

#FIG. 3 shows a view of four photo-responsive elements receiving lights from four orthagonal directions and mounted about the periphery of a conventional courtesy light which is mounted on the interior roof of an automobile.

#Reference is now made to FIG. 1 which illustrates a block diagram of the unique circuitry of this invention. Beginning with the photocell control of the lights, four photocell circuits 20, 22, 24 and 26 are mounted preferably as illustrated in FIG. 3 on the four sides of conventional courtesy light 28. Each of the photocells receive light from only one direction so that all of the directions are covered and the probability of stray light falling on each of the lamps in sufficient intensity to erroneously indicate a daytime condition is very small. Courtesy light 28 is normally mounted on the roof 30 of an automobile.

#The electrical outputs of photocells circuits 20, 22, 24 and 26 are applied to logic circuit 40 via respective amplifiers 42, 44, 46 and 48. As indicated briefly above, logic circuit 40 produces an output through an isolation/inversion circuit 41 to line 50 to turn off the lights during daytime only if each of the photocell circuits 20, 22, 24 and 26 are in agreement that a daytime condition exists. Similarly, logic circuit 40 produces an output on line 50 which turns on the automobile lights indicating that a nighttime condition occurs if any of photocell circuits 20, 22, 24 or 26 has detected a level of ambient light indicating that the lights should be illuminated.

#As mentioned briefly above, it is desirable to delay for a short time turning on the automobile lights to make sure that a detected low ambient light condition is really that of nighttime and not merely a transient shading of one of the photocell circuits. This is accomplished in the embodiment illustrated in FIGS. 1 and 2 by an oscillator circuit 54 which applies a train of pulses to time delay circuits 56 whenever oscillator gate circuit 58 is activated by a signal on line 50 indicating that one of the photocells 20, 22, 24 or 26 has detected a nighttime condition. The signal on line 50 from the logic circuit 40 and the isolation/inversion circuit 41 is applied to oscillator gate 58 via a gate driver 60.