Bright USB Powered LED Light

This Instructable will show how to build a very bright usb powered led light. This can come in very handy while working on your computer or lighting up your keyboard in the dark. Another possibility of this light could even be for a mood light, because it can be placed behind a monitor and shine onto the wall or ceiling. This is my first Instructable so I hope you enjoy!

Step 1 Materials

The first thing you have to do is gather your materials. ALL of the electrical parts I used to build this project were scrapped off old electronics I had laying around, and the tools needed are pretty common.

Things used for this project:
-X-acto knife
-Soldering iron
-Solder (duh :P)
-Hot glue gun
-Screw driver (for making holes)
-Electrical tape
-12 white LED's
-47ohm resistor
-Small switch
-Wire
-USB cable
-Small box (or anything that can hold the components)
-Scissors
-Sharpie/pen

Optional:
-Wire strippers
-Wire cutters

Comments

[acid4life]

Got a doubt , what it's the V of the LED's?

[vez87]

depends on the brightness, normal leds usually run at 1.5v super brights around 3.6v

[KT Gadget]

 It also depends on what compound is used to make the "light." Whites (no matter the size or shape of the clear housing, unless specified) usually run on 3.5-3.7V. I can't recall what the other colors run on but each vary differently.

[neeterxxi]

I really appreciate your simple yet very thorough explanation of your project, and with a USB cable nonetheless! I 2 R a noob and I'm slowly but surely learning how not to fear those teeny metal bits with names ending in "-or" or "-ode". I'm fortunate enough to be quite near to a Fry's Electronics so I shall return there and begin my foray into making my first simple circuits. :) I hope you plan to write more instructables, because I really enjoy your teaching style. Keep us updated into your newest electrical forays!

[Hunterman]

Well I'm glad I'm not the only one ;) haha and I'm happy to hear that you liked the instructable! I'm only 15... and without anyone to teach me...I do the only thing i can do, which is learn on the internet and try it out for myself. And while i'm sure there are millions of kids my age who could do something much better than myself, it was still fun doing this project, and i hope to post more intricate projects as i learn more about electronics.

[neeterxxi]

Why sir, you are a mighty bright and rather charming 15 year old if this old lady may say so herself. :) Is this something you plan on pursuing as a career one day?

[Hunterman]

Maybe not this exactly, but i would love to be an electrical or computer engineer once i get out into the real world

[neeterxxi]

That's what I meant, something in the electronics world or something related. Well you are well on your way and I wish you great success. And don't forget to post any new projects you're working on. :)

[mathews]

Its a good overall circuit, but with a single resistor, regardless(ish) of size you may have problems if one LED breaks with excess current; but as you said, each LED should have a resistor.
You can calculate the resistor by assuming that the voltage over the resistor is the supply voltage minus the voltage drop over the LED, in your case the resistor drop would be 1.4v.
To give a 20ma current, use Ohm's law
( v = i * R, R = v / i )
to get
R=1.4/ (20x10^{-3 )}
R=70R

I wouldn't be worried too much about the USB port, it will have a certain amount of short protection, and it won't provide more than 500ma anyway. Also looking at the wire layout, it looks to be thoughtfully done, and not overlapping. The electrical tape also ensures there will be no movement, and so no problem.

To make the LEDs brighter still, you might want to investigate PWM.

[Hunterman]

This was one of the most helpful comments I have ever seen :) thank you very much. I really appreciate it when someone takes the time to help me understand the reasoning behind why something works. I now realize what I did wrong, and I will most likely fix it in the Instructable so that people don't get the wrong resistor value. As for shorting out the cables, i made sure that they were much safer than they look by packing it with hot glue so that they won't move around, and I also went ahead put the electrical tape over the top to prevent any wire touching and moving around. I think the biggest problem I've had while doing electronic projects is the fact that I don't have access to a multimeter...and about 4 days before I did this i had just purchased one online...I'm still waiting for it in the mail. But a multimeter would greatly help me fix voltage and amp issues. Once again thank you :) ~Hunter

[uguy]

How did you come up with the 47 ohm resistor. It's value seems low.

[Hunterman]

But now that I think about it...it doesn't seem right to me either. I think the resistor should've been around 80 and connected to the leg of each led. But i'm unsure of how that value helped the circuit (because I R a noob)

[Hunterman]

Explain your reasoning. I'm kinda new to all of this so anything you could teach me would be great :) haha but as far as resistor value, i went to http://metku.net/index.html?sect=view&n=1&path=mods/ledcalc/index_eng to help me figure it out.

[mattthegamer463]

To be honest, I wouldn't use uninsulated wire for all those LEDs. If you shorted it out, you could damage your USB port. A better idea would be using a breadboard and having them all set up on a row of common connections. Excellent write-up, but be careful with that uninsulated wire.

[Hunterman]

I 100% agree with what you said, uninsulated wire is dangerous in general because of the possibility of shorting it. I'm pretty sure that was also mentioned in the Instructable though- I didn't have access to a breadboard and this was the quickest way for me to do it. One way to make it much safer though if anyone chooses to use bare wires like I did would be to load up on hot glue to completely insulate the wires, however that could get pretty messy... Thanks for the comment!