Introduction: USB Led Light

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

Step 2: Assembly

Picture of Assembly

Open keychain flashlight housing and remove all components. Solder positive wire of USB plug to the positive of the LED, solder the negative lead to the 100 ohm resistor, and solder the other end of the resistor to the negative of the LED. Install components in case.

Step 3: Test It

Picture of Test It

Connect to a working USB port and it should light up. :)

Comments (author)2011-11-18

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

markee2 (author)2011-08-29

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

bilal.a (author)2008-04-21

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

nodoubtman (author)bilal.a2011-08-17

Go there :

Good luck! :)

nodoubtman (author)2011-08-17

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!

amitesh.chanda (author)2011-07-02

nice one


ahmad2117 (author)2010-07-08

were do you get those male usb plugs i only find female

nbagf (author)2010-03-11

 windrago its called auto hot key. google it

windrago (author)nbagf2010-06-16

awesome thanks!

windrago (author)2010-02-10

 is possible to turn the light on/off through software?
I mean writing an app in C# for example.

ForenceKiller (author)windrago2010-06-15

You can do it...just disable that specific usb port...most modern languages support it, even script languages...

ranger_steve (author)2009-11-22

haha it does too!!

dna24 (author)2009-11-02

 so would this work if i tried to plug it up to my cell phone?

rakol1 (author)2008-03-09

i cant find leds anywhere and im looking for one so i can make a keyboard light

ranger_steve (author)rakol12008-03-10

try "the source" by circuit city. i'm not sure if they have "the source" in the us tho(if thats where u live)

poop11346 (author)ranger_steve2009-04-27

circuit city is gone from us I think but they have radio shack its cheaper to buy stuff in radioshack though (im from canada)

ranger_steve (author)poop113462009-07-07

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 (author)rakol12008-07-31

try radio shack. they should have drawers of electrical components

Jahoovi (author)2008-06-18

heck looks like u bought it

ranger_steve (author)Jahoovi2008-08-04


Colonel88 (author)ranger_steve2008-11-26

EVEN BETTER. Make a flexi neck onto the thing and you have something slightly better.

ranger_steve (author)Colonel882009-07-07

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.

crayzclown1 (author)2009-03-24

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.

polonium9 (author)2008-12-26

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.a (author)2008-04-21

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 (author)bilal.a2008-05-07

sure it will. I took one from the wireless human interface(keyboard, mouse etc) receiver and it worked

bilal.a (author)2008-04-21

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

ranger_steve (author)bilal.a2008-04-24

a is the type thet plugs directly into the computer

arnoldt (author)2008-03-10

Does it matter on the strength of the led?

ranger_steve (author)arnoldt2008-03-11

i'm not sure but i just used a blue led from "the source" but i'm not sure of the strength.

GorillazMiko (author)2008-03-09

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.

About This Instructable




Bio: Full time student in the Industrial Electrical Tech program. Wanna be redneck, driving my 93 ford ranger 4x4. Back yard mechanic... well heated garage mechanic ... More »
More by ranger_steve:Power Distribution BoxDIY "POD GX studio"Rockband Kick Pedal Kill Switch!
Add instructable to: