The USB Powered LED CD Lamp

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Introduction: The USB Powered LED CD Lamp

About: Hi all, I'm a college student in the copenhagen technical college. I'm currently working with 3D printers and I'm building my own RepRap.

The USB powered LED CD lamp is a very useful gadget. It's powered by the USB port, so you don't need any external power supply. The stiff mounting wire, I used acts as a gooseneck and lets you bend the light source in different angles and directions.

Step 1: Get the Parts

Here is a list of the parts you'll need to make this lamp.

4 CDs or DVDs (and if you're rich, you can even use Blu-ray discs or HD DVDs)

7 5mm White or warmwhite LEDs, I used warmwhite, because that I'm tired of the cold light, you get from the ordinary white LEDs. (I've posted some pictures, so that you can see the difference between the white and the warmwhite LEDs)

7 Resistors for the LEDs. I calculated, that my resistors should be 68 ohms. you can find a very good resistor calculator here.

Some electrical mounting wire. Should be the stiff type (the one with only one thick cupper conductor)

5 AA batteries preferably Duracell, cause they're the heaviest (the batteries are just there to act as a counterweight. Without them, the lamp would just tip over and fall).

A switch (optional)

Some ordinary hookup wire.

A USB male A connector with cord (I got mine from a broken webcam)

Some wire without insulation.

Step 2: Prepare the CD That Holds the LEDs

Drill the 7 5mm holes for the LEDs. Use a pair of compasses to mark, where you'll drill the holes. Remember, that when you drill the holes, do it on foil side. If you don't, you may rip off some of the foil. Move your mouse over the yellow boxes to view instructions.

Step 3: Mount the LEDs and the Resistors on the CD

Now, mount the LEDs and resistors. Move your mouse over the yellow boxes to view instructions.

Step 4: Mount the 2nd CD and the Stiff Wire

Glue the second CD and the stiff wire onto the CD, where the LEDs are mounted. This is simply done by using a hot glue gun. Move your mouse over the yellow boxes to view instructions.

Step 5: Start Making the Base

Now, start making the base. The pictures will guide you trough this process. Move your mouse over the yellow boxes to view instructions.

Step 6: The Counterweights

Now, it's time to mount the counterweights (the 4 of the 5 batteries). Simply glue them on with one of my favorite weapons: The Hot Glue Gun.

Step 7: Final Assembly

In this step, I'll show you how to mount the rest of the things: the last counterweight, the switch, the USB cable and the wiring.

Step 8: Plug 'n' Light

Now hook your lamp up to the USB port and have fun. Hope you enyoyed this Instructable. Leave me a comment below.

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    175 Discussions

    I have a challenge here. I have a power source that is 53v DC and I want to use 7 Super bright LEDs. I'm new to electricity and I think that it will blow the LEDs since they run on a few volts each. What size resistors do I need use? And where do I install them? I need to use the 53v source. Please show calculations. THANK YOU in advance =]

    2 replies

    add the voltages of the LEDs
    subtract from the 53v source
    divide with the LED current , most LEDs have 20mA so it is .02 A

    so
    R=(V1-V2)/.02A

    Best way in your case is to put them in series (i.e. you chain the LEDs and then you add a resistor). But I'd discourage you using that power supply for this application.

    High brigthness LED could draw significantly more than 20mA...

    Let's suppose you have 7 LED rated for 1.5V @100mA

    You would need a resistor sized like this:

    R = (53V - 7*1.5V)/100mA = 425 ohm

    So your LED will use this power

    P = V * I =7*1.5V * 100mA = 1,05 W

    and your resistor will use

    P = (53 - 7*1,5) * 100mA = 4,25W ...

    That means that you would not blow your LEDs but you'll probably blow your resistor, or if you have a resistor rated at least 5W, you'll end up with a heater more then a lamp, as the resistor will use 4 times more power than the LEDs...

    For this kind of application you should use a DC/DC converter, but it's definitely no subject for a novice...

    I really like this project. Really creative and elegant. I've made a similar project on my blog and featured you.

    Does this double the consumption of the energy from the laptop or desktop?

    leds r always connected in parallel.with a 1k resistor each,try in series,they wont light.am good in this.

    hello can someone tel me why i can powered Led lights by USB???

    well i made my usb lamp,
    but i connected all the led in series
    but the pro is i get a notice on my pc
    power serge on usb ...
    whts to do with tht ??

    1 reply

    Hello! : How do you get 68 Ohms resistor ??

    So : 7 LEDs 20 mA each, 3.5 V each to run, 5 V usb max.

    R = (5 - 3.5) / (0.02 * 7) = 10.71 Ohms near value = 12 Ohms. Which is far away from 68 Ohms resistor.

    Can you give me your trick? :)

    Have a great day! :)

    Just a suggestion. You may need just one resistor. Just wire it so its between each LED and power. I'm guessing a 1/2 or 1 watt resistor should do the trick... It will save a little solder and 1/2 dozen parts ... Nice job. : )

    9 replies

    It is a bad idea to wire LEDs in parallel as you are sugesting.

    I'll quote from The Electronics Club:

    Connecting several LEDs in parallel with just one resistor shared between them is generally not a good idea.
    If the LEDs require slightly different voltages only the lowest voltage LED will light and it may be destroyed by the larger current flowing through it. Although identical LEDs can be successfully connected in parallel with one resistor this rarely offers any useful benefit because resistors are very cheap and the current used is the same as connecting the LEDs individually.

    "If the LEDs require slightly different voltages -only- the lowest voltage LED will light " No. And how much is 'slightly' anyway ? Is 2v 'slightly' different than 3v ? As long as the resistance is appropriate for each LED and the resistor can handle the load, there's no problem. Since this DIY uses the -same- LEDs, they need the -same- current, so there's no problem. And, as the last line of the quote says,"...and the current used is the same as connecting the LEDs individually." Thats my point. Its the same. It's the same current unless the LEDs -are- different, and if they ARE different then use different resistors, not 7 of the same ... Try it yourself. Its easy to test and see who is right here... I like elegant solutions, not wasting parts, and not scaring people away from simpler solutions without understanding why. If you like wasting parts, I have lots of projects for you to try ... ; )

    You should post up some instructables of your own. A.I. and I both have posted instructables where we wired circuits for LEDs. Not that simple LED circuits are that challenging but you might be able to demonstrate what conditions are required to use a single resistor safely.

    Thanks for the suggestion. AI's project is a good candidate for using one resistor for all ( not each ) LED. As long as each LED has the same specs, and the resistor is properly sized, it would work. I started playing around with using the PC power supply as a source of power for projects including an LED Lamp.... I'll keep you posted. Regards.

    I'm not scaring people off, I'm stating the generally accepted rule of circuit building.

    Sorry. The Electronics club doesn't have it quite right.

    Its NOT a generally accepted rule. Its a waste of parts, and there's no logical justification for it.

    I will say that as a design rule, simpler is better.

    Here's a link that discusses LED wiring more fully and accurately than the Electronics Club.

    From circuitry 101:
    http://www.theledlight.com/ledcircuits.html