(Last Updated On: January 21, 2019)

Automatic Street Light using 555 Timer

This Electronics Mini Project includes Automatic Street Light using 555 Timer Circuit IC. Normally the turning on/off of the light is done manually using a switch whenever there is need of a light. But here we have designed a system where there is automatic turning on and off of the light whenever required.



When darkness is detected then the sensor circuit gets activated and switches ON automatically and when there is other source of light during daytime, the street light gets OFF. Also this circuit can be used to adjust the sensitiveness of the light. The circuit is simple and based on 555 timer IC and LDR.


Components Required & Circuit Diagram

The circuit is very simple and cheap as well. It can be implemented using following components:

1. L.D.R (Light Dependent Resistor)
2. IC NE555 with Base
3. LED1 & LED 2 (Light Emitting Diode)
4. Variable Resistance of 47 KΩ
5. On/Off Switch
6. 9v Battery with strip
7. 47K Trimmer or Preset
8. 330E Resistor

Now assemble the given circuit below in zero pcb or vero board as per circuit diagram.
Automatic Street Light using 555 Timer Circuit


Working of the Automatic Street Light using 555 Timer Circuit:

LDR is a Light Dependent Resistor whose value depends on the quantity of the light which is falling on it. It has resistance of almost 1 mega ohm when it is in total darkness, but its resistance is about 5k ohms when exposed to full brightness. The IC 555 timer is used to control the operations of the circuit which acts as a comparator circuit with pin 6 connected to positive terminal. The output goes high when the pin no. 2 i.e trigger pin goes one third of the supply voltage. Similarly its output goes to low when output is above one thirs of the voltage. For detection of amount of light LDR is used as a resistor to adjust the circuit voltage.


The circuit is cheap and economic and can be made easily. On large scale the circuit can be used with solar cell as energy source and big light source can be used at night and instead of manual operation automatic operation can be implemented.


Video Tutorial: