Automatic Night Light Kit

Description

This circuit senses the light intensity from surroundings and find whether its day or night. A light sensor known as LDR( Light Dependent Resistor) whose resistance varies with Light intensity is used to detect the darkness and automatically turn ON the LED and Turn OFF the LED when there is Light. LDR behaves based on the below mentioned conditions. A pair of Transistors are used to Switch the LED (Load).

High Resistance on LDR= Darkness

Low Resistance on LDR = Brightness

Fun Fact: If you are wondering how Solar Street Lights turn ON and OFF automatically, Similar Circuits will be installed in them.

Connect all the components on the breadboard and power it using the 3V Battery with correct polarity. Cover the LDR Darkness Sensor to test the circuit. The LED Should Turn ON if LDR is covered and turn OFF when Light Falls on the LDR Sensor.

Where this can be used?

This circuit can be used in living area or garden area as a emergency lighting when there is sudden power outage and can automatically turn ON Light.

What electronic components are required?

1. 2N3904 Transistor
2. Breadboard (Want to know what is breadboard and how it works? check this link out )
3. Battery 3V
4. LDR
5. LED
6. 10K Resistor (Confused with colour code and not sure which one is 10K? check this video out to see how to measure the resistance using the multimeter)
7. 1K Resistor
8. Some jumper wires

Circuit diagram

 

Step-by-step video build guide to the Project

Click the link to below to watch the video

Automatic Night Light Build Guide

See how it works after assembling the components 

Future Improvements

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