Making Automatic Street Light

• Needs no manual operation for switching On and OFF. When there is need of light it automatically switches ON. When darkness rises to a certain value then sensor circuit gets activated and switches ON and when there is others source of light . Day time the street light gets OFF. The sensitiveteness of the street light can also be adjusted. In our project we have used L.E.D for indication of bulb but for high power switching one can connect Realy (electromagnatic switch) at the output of pin 3 of I.C 555. Then it will be possible to turn ON/OFF any electrical appliances connected all the way throught realy.

Component used:
9v Battery with strip switch.
L.D.R (Light Depending Resistance)
I.C NE555 with base.
L.E.D (Light Emitting Diode) 3 to 6 picess.
Vriable Resistance of 4.7 kilo ohms .
P.C.B (Printed Circuit Board of 555)

Components:

• Battery.
• L.D.R (Light Depended Light)
• L.E.D (Light Emitting Light )
• Variable Resistance.
• P.C.B (Printed Circuit Board)

Working :

When light falls on the LDR then its resistance decreases which results in increase of the voltage at pin 2 of the IC 555. IC 555 has got comparator inbuilt, which compares between the input voltage from pin2 and 1/3rd of the power supply voltage. When input brightness, input voltage rises so we obtain no positive voltage at output of pin3 to drive realy or LED, beside in poor light condition we get output to energy.