How to Make an Light Sensor and Dark Sensor

Hi Everybody... , and this is my second instructable so please give me advise and point out the areas in which i can improve.




Please after looking to my project give an honest rating.

Step 1: Things That You Will Need

1)LM358 IC
2)LM7805 IC
3)2 LEDs
4)2 LDRs
5)Breadboard
6)3 9v batteries
7) wires
8)Two variable resistors of 10K

Download the data sheet of LM358 and LM7805 IC.(You may need it !)
Link of LM358- http://www.datasheetcatalog.com/datasheets_pdf/L/M/3/5/LM358.shtml
Link of LM7805- http://www.datasheetcatalog.com/datasheets_pdf/L/M/7/8/LM7805.shtml

Step 2: Circuit Diagram

Remember that the LDR doesn't have a negative or positive terminal !
Connect the first terminal of the LDR to positive and second terminal through variable resistor to negative.Then start varying and when you get a vary for example(.58 v to 1.1v) or If the vary is of good range ,then also the circuit will work.After that take a wire in between from LDR & variable resistor and put in the third pin of the LM358 IC.

Please make the circuit given in the diagram.
The circuit should be made in a good light.

Step 3: How the Circuit Looks

Step 4: How It Works

In my circuit the left LDR is light sensor and the right LDR is Dark sensor.When you put hand on left LDR the 1st led stops glowing.
And when you put your hand on right LDR the 2nd led starts glowing.

Comment if you guys have any problem !

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