Automatic Headlight Circuit

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Automatic headlights are like any other headlights you’ll get at the front of the car except that when the car is on and it is dark, they will activate automatically without the driver needing to press a manual switch. And they will stay off when conditions are clear and during the daytime. So cars with automatic headlights can be turned on or off manually by the driver with the car’s controls if they choose. But if the driver selects the headlights to run as automatic like default then they should be quick and smart enough to take care of this job for the driver. Here we design a simple circuit, by fixing this circuit driver can concentrate on driving without thinking about the headlight of the vehicle.

Hardware Required

S.noComponentValueQty
1.ICNE555 Timer1
2.LDR1
3. Relay1
4.TransistorBC5471
5.Switch1
6.Manual Switch1
7.Bulb1
8.Resistor4.7KΩ1
9.Variable Resistor100KΩ1
10.Diode1N40071
11.Capacitor0.01uF,10uF/16V1,1
12.Connecting Wires
13.Battery12V1

Circuit Diagram

Construction and Working

As we can see, the main part of the circuit is IC 555 and LDR. Here LDR works as a trigger input sensor, and the output of IC 555 is connected to the relay and headlight. When the vehicle moves during the daytime the LDR offers low resistance, hence the positive supply given to the triggering pin. This doesn’t turn on the IC 555 into pulse oscillation. If the vehicle enters dark conditions then the LDR offers high resistance, and the negative supply through VR1 rises and triggers the IC 555. Hence this will activate the output so that headlight turns on. Here we need a 12V power supply to power the circuit.

Applications

Can be used in different vehicles, such as when they enter somewhere dark like a tunnel, for instance, then the automatic headlights can activate and deactivate accordingly.