The Smallest USB LED

Here is the smallest USB LED you've probably ever seen! It uses a USB plug made with a piece of perfboard, so you should already have everything needed to make this. No cutting up USB cables here!

This kind of homemade USB plug could also be used for other things, like repairing USB cables.

Step 1: Supplies

All you need for this project is:

A Soldering Iron
150-200 Grit Sandpaper
1k Resistor
Blue LED (Other colors will work just fine, too)
Small Piece of Perfboard
X-Acto Knife

I used a 1k resistor because I just wanted a nice looking light, not a blinding one. ;P Feel free to use a different value if you choose.

Comments

[Ploopy]

I'm building one as soon as I get the ressistor

[Ploopy]

Cool instructable!!!

It would be even cooler to build one with surface mount components and a mini USB.

[ZaneEricB]

Very nice....I used a unused USB in my TV to power a bluetooth Wii bar... I might use this design for say...? I have an idea!! ill share later...BUT

VERY NICE!!

[alpesh.masarani]

how to calculate resistor value for against usb port output voltage against. plz help

[Roaraar]

USB ports are 5 volts. A typical blue or white led is around 3.2v, to be safe, we'd use 10ma on it,
so using so by going (5-3.2)/0.01= 180 Ohms

So using any resistor above 180 ohms is absolutely safe, but using a resistor higher than maybe 1000 Ohms will not be very bright/not light up at all.

However, I commonly use 100 Ohm resistors for 5v, and I have no problems with that.
It just means I get 20ma instead of 10

[GorillazMiko]

How come in the 1^st image and 2^nd to last image, the resistor shows brown, black, red, gold OR gold, red, black, brown... I can't really tell, but in step 1, your yellow note over the resistor says color code: Brown, Black, Red?

Do you know how you can figure out which way it goes?

Like lets say there are colors WXYZ.

The resistor is eithe WXYZ or ZYXW, how can you tell?

(In the image, is this the resistor you're using?)

[agm88]

(removed by author or community request)

[agm88]

brown black orange 10k ohm and it doesnt matter the polarity eathier
this message was intended for beggieners

[Gamernotnerd]

Metallic colors always go last, like gold, or silver.

[kill-a-watt]

if you are asking, no the polarity of the resister does not matter.

no, it does not matter if the resister comes first or the LED

and you read resisters from the band that's closest to the end toward the gold ban (sometimes silver or wide-stripe brown)

these are brown, black, orange, gold = 10 K ohms with a ±5% tolerance

[agm88]

thank you

[brandon20904]

It doesn't matter witch color first, but they do have to go on positive.

[emuman4evr]

Why do they go on positive, Ive never figured this out, if electrons flow from negative to positive wouldn't it make sense for them to go on the negative?

[1up]

... Don't they flow from positive to negative? And it actually doesn't matter if the resistor goes on the positive or the negative terminal.

[gomibakou]

Current flows (well really the electrons flow) from negative to positive. But, for study, usually its represented as the opposite: from positive to negative, but it's a representation not the true physics behind. I learnt this way and i'm fine with this, regardless i know the real current flows from negative to positive.

For a resistor, since it's a pasive component with no polarity, it doesn't matter where is the positive or negative voltage. The key is the POLARITY. It hasn't.
A LED has... a capacitor has or hasn't xD depends on the type...

[emuman4evr]

I read in one of my dad's electrician books that it was believed that electricity flowed from positive to negative but then proven it actually flowed from negative to positive. So it doesn't matter?

[1up]

Well, a quick Google search confirmed that you are technically right. Electrons are negatively charged, therefore they have a tendency to flow towards the positive end of the power supply.

But, in electronics, it is said that they flow from positive to negative, so as not to be confusing.

And again, it does not matter if the resistor is hooked up to the positive side or the negative side.

[gomibakou]

Electrons are the only that can move... remember the atomic structure, protons and neutrons are "glued" together to form the nucleus and electrons are orbiting "around" it. Protons can't move, because you have to break the nucleus for that... and it's called nuclear fision xDDD (used in current nuclear power plants). Elecricity is only the electrons flowing trying to achieve a electric equilibrium... or electric potential if you like it. As only the electrons can flow... the direction of the current must be from the negative terminal to the positive, or i should say from the terminal with more electrons to the terminal with less electrons (it's "like positive" since it is not so negative as the other terminal)... that is the -resuming- the physics behind. I prefer thinking it flowing from positive to negative xDDD

[Berserk87]

this is what you guys are talking about.<br/><br/><a rel="nofollow" href="http://www.rkm.com.au/ANIMATIONS/animation-graphics/circuit-diagram.jpg">http://www.rkm.com.au/ANIMATIONS/animation-graphics/circuit-diagram.jpg</a><br/><br/>Conventional Flow, and Electron Flow.<br/>

[1up]

Ah, yes, perfect. Thanks for the diagram.

[dark sponge]

The gold band comes last, and is there on almost all resistors. The first three bands give the resistance and the last band (gold) gives the tolerance. The resistor he is using in this instructable is Brown-Black-Red. The resistor in your picture is not the right type, you need a 1k resistor (Brown-Black-Red) and yours is a 10k resistor (Brown-Black-Orange).

[GorillazMiko]

Oh okay, so gold is always last? That's how you can figure out which order it is?

Thanks, that helps a lot!!! :-)

[Grey_Wolfe]

Sometimes it's silver instead. But the premiss is the same.

[1up]

A gold band means 10% tolerance, silver means 15% tolerance. No band means 20%.

[dark sponge]

Actually, silver is 10% tolerance, gold is 5%, red is 2%, brown is 1%, and none is 20%

[1up]

Oh, yeah, whoops. I must've gotton confused. I just realized I wrote 10% for gold.

[Grey_Wolfe]

Didn't remember the exact tolerances, been a few years. But it's good that you through it out there.

[Grey_Wolfe]

Duh, how about "threw" it out there. Not sure what planet I was on right then. lol

[Gh{O}sT]

YAY I havenoidea what your talking about!

[Radioactive_Legos]

Depending on the LED you use, you'll need a different resistor. If you know the rating of the voltage and amperage of the LED, you can figure out the necassary resistance. The equation is R=V/I. R is resistance, V is voltage and I is amperage (not sure why, there's no "I" in ampere, nor is there one in team :^{) ) I just finished an USB powered LED lamp in an Altoids Smalls tin. Not very "small" compared to this, but it came out well. It has a flexible neck and a 7000mcd LED.}

[1up]

I just have always remembered that gold is always last, sorry for the confusion! :)

[LAS]

The LED and Resistor connections are reversed between STEP 4 and STEP 5 images

Step 4 have Cathode (-) [LED Flat Side pin] on right
Step 5 Have Cathode (-) [LED Flat Side pin] on left

In both the resistor is on the Anode (+) side of LED so it appear one set of photos was done with a Mirror.

PS: Step 5 with Cathode (-) GND on left is the correct way around ;-)
http://www.addonics.com/technologies/usb3_tutorial.php

[out-of-the-box]

i would imagine its greatest purpose would be to test usb polarity and if its working or not? i love it none the less.

[out-of-the-box]

haha this is fantastic!

[kevins82]

Thats awsome i woud like to make video about this small project when parts arrive, if you allow?

[1up]

Of course, I don't mind at all. :)

[kevins82]

I tried it today but i did something wrong and it just dosent want to light :D i'v tried it twice :D but my led's are too lazy to light up :D :D

[batonas]

like

[utest_jays]

test

[petalee]

This is really cool, I'd like to try this out sometime :)