Picture of USB led light
USB led light

Step 1: Materials

Picture of Materials
USB plug and cord
Blue LED (any other color will work too)
100 ohm resistor
Case or housing to hold the led ( I used a cheap mini keychain flashlight housing)

Tools Needed to do this project

Soldering iron
Screwdriver to take apart case
G.one3 years ago
i also have a USB cable but in that there is no output from black wire so connected to the green wire and by using a multimeter  it shows 5v and i connect LEDs to it without using resistor my PC is showing that the USB device is not recognizable please help me 
and i can't afford another USB cable
markee24 years ago
Tnx for info. I have the schematic of the LED light  , might help if you planning to modify the circuit depending on your available materials
copied from

USB led light schematic.jpg
bilal.a7 years ago
thanks so much, but what i would like to know is, the voltage of the usb for multiple LEDS, can some one help me plz, and email me on mr_ucantcme@hotmail.com
Go there : http://www.ledcalc.com/#calc

Good luck! :)
nodoubtman4 years ago
Hello! To power up a blue light which is (2.5V), you have to put a resistor of 125 Ω, because if you put a resistor of 100 Ω, you will burn out your blue led. here's the formula : (Vc - Vf) / 20mA (1 led) *1000 = 125 Ω. If you put up a resistor size of 100 Ω : ((5 - 2.5) / 100 Ω) * 1000 = 25 mA, a single led is 20 mA, so your will burn out your LED.

thank you!
nice one
stevie1 (author)  amitesh.chanda4 years ago
ahmad21175 years ago
were do you get those male usb plugs i only find female
nbagf5 years ago
 windrago its called auto hot key. google it
windrago nbagf5 years ago
awesome thanks!
windrago5 years ago
 is possible to turn the light on/off through software?
I mean writing an app in C# for example.
You can do it...just disable that specific usb port...most modern languages support it, even script languages...
dna245 years ago
 so would this work if i tried to plug it up to my cell phone?
rakol17 years ago
i cant find leds anywhere and im looking for one so i can make a keyboard light
stevie1 (author)  rakol17 years ago
try "the source" by circuit city. i'm not sure if they have "the source" in the us tho(if thats where u live)
circuit city is gone from us I think but they have radio shack its cheaper to buy stuff in radioshack though (im from canada)
stevie1 (author)  poop113466 years ago
ya our radio shack went out of buisness when i was like 4. so now i have to eithe buy stuff from the internet or go get ripped off at the source.
jgeekw rakol17 years ago
try radio shack. they should have drawers of electrical components
Jahoovi7 years ago
heck looks like u bought it
stevie1 (author)  Jahoovi7 years ago
EVEN BETTER. Make a flexi neck onto the thing and you have something slightly better.
stevie1 (author)  Colonel886 years ago
one of my parents friends fly's for air Canada and goes to hong kong and gets us all sorts of junk. he bough me a usb fan with a flex neck but when i plugged it in to the computer it said it was using to much current so i ripped off the fan motor and put four white leds on it. it works really well.
crayzclown16 years ago
would it work if i hooked the LED straight to the wire?
Technically, it should work without the resistor, but one can never be too safe. From my own experience with LEDs and USB cables, the resistor also helps reduce the heat emitted by the current flowing through the circuit.
polonium96 years ago
i made this with no soldering and it works amazingly BRIGHT DOLLAR STORE LED from a little light up car WORKS GREAT and to all who read this TRY IT you will be amazed I AM USING IT RIGHT NOW
bilal.a7 years ago
where can i get a USB cord and plug from, if i use a printer usb cord, but remove the end that connects to the printer will it work?
awkrin bilal.a7 years ago
sure it will. I took one from the wireless human interface(keyboard, mouse etc) receiver and it worked
bilal.a7 years ago
sorry about all the questions, does the USB cord and plug need to be a sereis a or b? or could it be any type of USB cord and plug, please and thank you again
stevie1 (author)  bilal.a7 years ago
a is the type thet plugs directly into the computer
arnoldt7 years ago
Does it matter on the strength of the led?
stevie1 (author)  arnoldt7 years ago
i'm not sure but i just used a blue led from "the source" but i'm not sure of the strength.
Great job! Extremely easy to do, great pictures, very small, and not as hard as all the other ones. Great job once again, parts are easy to get, very cheap, I just might do this soon.