Today I will be showing you a method to build a USB LED Light for you Laptop, if yours don’t have. This is not a new invention or development. It is the article for those who don’t want to buy the product and save some pocket money. The parts we will be using to Build our USB LED Light would be available at you home, somewhere lying in the corner for no use. Let’s use those material and make them Useful.
- USB Wire Cable ( Data Cable )
- Wire coating ( Not necessary )
How to take Power from USB Cable
Well main question arises, how are we going to take power from USB Data Cable. The USb Data Cable contains four wires in it, two which are for Power – Ground, other two are for transfer of you data. This is evident from the fact that you Data Cable is used for Both Charging as well as tranferring the data which includes copying, deleting or moving. We will use those two power and ground wires for our LED and leave the other two .Hence our LED will be able to glow.
The next question that arises is Why do we need to Use the Resistor, Resistor is used beacuse Voltage requirement for LED is 2V But the USB Port supplies 5V, so inorder to have 2V accurately. We use resistor in series to the LED so that there occurs the Voltage drop across the reistor.
Calculating Value of Resistance for LED
Total Voltage Supplied: 5 Volts
Voltage across LED: 2 Volts (If you take LED of other Voltage rating then change it)
Voltage drop across Resistance: 3 V
Current Reqd: 20 mA (milli Ampere)
R = 3 / ( 20 * 10 ^ -3 )
R = 150 Ω (ohms)
How to Identify Positive and Negative ends of the LED
The LEDs are biased devices mens they only work if the current flows through them in one direction. Therefore it tis neccesarry to identify the pins of the LED for making it work. There are various methods to identify the Pins of the LED: most common includes identifying by observing or by Multimeter.
You will se the that the two Legs of the LED are not Symmetrical, one Leg is longer than the other one. The longer leg is the Anode and shorter one is the Cathode.
The Current from the LED flows from Anode to Cathode.
How to Do it?
Take any old Data Cable lying in you home of no use, if you buy a new one then this project is going to be of no use as there is product available for USB LED Light that is available at a slighlty higher price than the cost of USB Cable. So take the old one!
Cut the Data Cable from the Side of USB Port, There would be four Wires coming from it. Two for Power Transmission, other two for Data Transmission as I have explained in the theory part.
Connect the Resistor to the 5V line of the USb Cable then with the Postive End of the LED. You have to keep in mind these things, if you do it wrong then you going to short circuit. To take precaution read How to Identify the 5 V line of USb Cable in Theory Part.
Now Connect the Negative End of the LED to the Ground line of the USB Cable, for the making the connection complete.
Now you connections are complete, The next you need to do is coating for your wires. To make it flexible you may use the Coating of other wires present in you home like the Coating of the wire of Iron, Washing Machine or any other electrical equipment.
Last thing you need to do is the provide the cap for your LED or may not provide, it will be fine.
Hence you USB LED Light is ready to Use, Now you may plug it into your USB Port. You USB LED Light is Ready to USE.