Design and Development of an Automatic Automobile Headlight Switching System

O. Akinsanmi, A.D. Ganjang, H. U. Ezea

This paper presents the design and development of an automatic automobile headlight switching system. Headlights of vehicles are inherent for night driving.  These bright headlights which assist the driver for vision, while driving at night, pose a great threat to the other road users coming in the opposite direction. The bright light of the vehicles causes a discomfort in the form of a glare to the oncoming driver. As a rule in night driving, every driver is expected to switch their headlights from high beam to low beam once they spot an oncoming vehicle within 150 metres in order to reduce the glare, but this practice is hardly adhered to. This is one of the major causes of accidents during the night, as the opposing driver will not be able to see the road clearly due to the brightness of the oncoming vehicle's lights. This automatic headlight switching system switches the high beam lamp to low beam as soon as it senses a vehicle approaching from the opposite direction and switches it back to high beam when the cars pass each other. The prototype is an electronic circuit that incorporates the use of a 12 volts power supply which is provided by the car battery itself, a light dependent resistor which acts as the sensor, a potential divider network which serves as a comparator to trigger an NPN transistor connected to an SPDT relay which does the switching. It was designed, constructed, tested and it worked, sensing to a distance of 147 metres. This design minimizes night accidents occurring as a result of this glare by the introduction of automatic headlight control in automobiles. This solves the problem of switching which is not done most of the time, reduces the stress of continuously switching beams manually, hence giving the driver more concentration on the road while driving at night. This paper brings to limelight the need for manufacturers of automobiles to inculcate this in modern cars to improve on the deficiency of the existing ones.