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Willuknight
26-12-2004, 08:58 PM
USB Snake light
Inspiration from http://www.metku.net/

An easy and fun mod which doesn't take too long, nor cost too much.

All writing and photographs are copyright of William Stewart, 2004. Feel free to tell your friends about this mod, or post about it elsewhere on the net. I do NOT give permission for people to copy and paste this article and publish it elsewhere. If you would like to ask my permission for distribution, please contact me on Willuknight @ gmail .com

DISCLAIMER: It is not my fault or responsibility for you or your computer parts. Nothing happened to me while I made this mod. HOWEVER I accept no responsibility any damage or injury caused while following this guide. By reading the rest of these instructions, you signify that you have read and agree to this Disclaimer. Have fun !

NOTE: Do not try this with multiple LEDs / different resistors unless you know what your doing. If in doubt, ask someone experienced with electronics. If you follow the guide and get the same LED / resistor, i doubt you'll have any problems. If you get a different value resistor or LED, you could blow your USB controller.

Parts Needed:
(DSE = D ick Smith Electronics)

1x USB Cable
(I got a spare USB printer cord and chopped off the printer end)

1x LED
(I got an Ultra bright White LED from DSE for NZ$7.95. Part number Z3980

1x Resistor.

Type will vary depending on what LED you use. If in doubt, ask someone at an electronics store.
If you use the same LED I used, then you need the R 1058 Resistor @ DSE

Electrical Tape
Or you could be cheap and use sellotape.

EXTRA'S

Cable Cover
I got a 3meter length at Repco for $9. You can also buy rubber covers for cables from Payless Plastics. They look really good inside your case to cover up Molex cables, ect. You could also try Heatshrink, ask at DSE

Lamp Mount / Cover
Use your imagination. I found a loose Icicle Christmas light cover, worked quite well.

Wire
If you get some wire, then you can make the light act like a snake light, i.e. bend it and it will hold its shape. Really Handy.

You can get an old wire Coat hanger for this, or any other sort of wire that is easy to bend, yet will hold up the weight of the light. I only have thin wire spare, so I folded it 4x for enough strength.

TOOLS:

Soldering Iron and Solder

Utility Knife

Wire cutters

Also handy is a vice or something to hold the wires in place.

--------------------------

Instructions


Step One: Skinning
a) Get your USB cable, cut off the end you don't want. Cut off 5cm of the plastic cover of the cable with your utility knife, being careful not to cut any wires (its good practice).

There will be about 4 wires in the USB cable, and possibly a foil shield, surrounded by a weave of outer wire shield.

b) Pull back the shields, until you can see about 5cm of the Coloured wires.

c) The only wires we need to use are the Black wire and the Red wire.

Red is 5volt, Black is Neutral.

Trim back the plastic cover of these wires, until you can see about 3cm of the copper wire. Be very careful not to cut any of the copper wires. If you cut too many, you will have to trim back another 3cm.


http://img.photobucket.com/albums/v336/willuknight/Assorted/USBLight/Pic1.jpg

Step Two: Soldering

a) Get your LED, and look at it. The longer leg is the positive wire, the shorter is the negative.

You may want to trim the legs back so they're not so long, BUT BE CAREFUL NOT TO FORGET WHICH LEG IS + AND WHICH IS -
My suggestion: trim the - leg first, then make sure you leave the + longer. Use Wire cutters to trim the led legs.

(Just a tip about soldering, the less solder the better, i.e. use enough for the job, but not a big blob of solder. Also be careful not to melt the LED casing, resistor or wire sleeves with the soldering Iron. I've ruined one component that way.

You may want to do what I do, and use a cardboard shield. Just get a small cardboard rectangle, and cut a line into it about halfway. Then put the wire you want to solder through the cut. The idea is that the cardboard protects the rest of the wire/components. Then when that wire is soldered, tape it up before moving to the next one.)

http://img.photobucket.com/albums/v336/willuknight/Assorted/USBLight/Pic2.jpg

b) Now solder one end of the resistor to the + leg of the LED.

c) Then solder the red wire to the other end of the resistor.

d) Now solder the Black wire to the short leg of the LED.

Now test your light. All going well, it should work.

If not, check that none of the wires are touching each other, and that the Black and Red lines do not touch anywhere.

Now you have a functioning light, but itís still pretty ugly and fragile, so you need to finalize it.

You can bend the wires around if you need to, but make sure they don't touch each other, or break
----------

Step Three: Make it Pretty

a) Now, if you have a led mount, affix the led to the mount. remember to make sure no exposed wires touch.

b) Wrap up the end with electrical tape, and cover all exposed wires. Remember the other coloured wires, and the cable shield we didn't use ? you can cut this back, or tape it under. Remember not to let any exposed wire to be in contact.

c) Now get your heavy gauge wire, for the snake light part of your light. This wire should be weak enough to bend without too much effort, but still strong enough to retain its shape, and bear the weight of the LED.

Wrap the wire around the cord and tape it at intervals of 5cm or so, for strength.

Your USB light should now look like this:
http://img.photobucket.com/albums/v336/willuknight/Assorted/USBLight/Pic3.jpg

You can spray paint the cord, or wrap it in cablesleeving or heatshink if you want it to look better.

My Finished Product :
http://img.photobucket.com/albums/v336/willuknight/Assorted/USBLight/Pic4.jpg

http://img.photobucket.com/albums/v336/willuknight/Assorted/USBLight/Pic5.jpg

Well, that was exciting. All up it cost me $7.99 to make this, not including USB Cable, Electrical tape, solder, LED mount, Cable Sleeving and 1 hour or so time. Thatís about what it would cost to buy one on trade me :D

However Iím still pleased I did this, as it was enjoyable, educational and now I get to have my very own home made USB Accessory!

Sorry about the lousy photos. My current 2mb camera isn't good at dark photos or close-ups. I lost my good Sony Cyber shot in a fire :(

I hope someone else out that takes up the challenge, costs could probably be saved by buying a normal LED instead of an Ultra bright one, which cost 99% of my budget.

I'll defiantly be trying variations on this mod, maybe some LED spotlights inside my case :)

Cheers,

Willuknight AKA William Stewart

Codex
27-12-2004, 07:55 AM
i might try this......

robsonde
27-12-2004, 09:41 AM
I have been thinking of doing this for some time.....

nice of you to write it all up for others.

Eric
27-12-2004, 12:23 PM
here is another version
http://www.siliconchip.com.au/cms/A_30612/article.html

Willuknight
27-12-2004, 01:18 PM
Mines customised for New Zealanders though :D

Its probabably cheaper and easier to go buy yourslef one from trademe, however nothing beats having made something like this yourself :D

Greg
27-12-2004, 04:40 PM
Mines customised for New Zealanders though :D

Its probabably cheaper and easier to go buy yourslef one from trademe, however nothing beats having made something like this yourself :D

Hardly seems worth the hassle when you can but one which looks a lot smarter and costs less

http://www.dansdata.com/usbthings.htm

http://www.dansdata.com/images/usbgadgets/rgblight800.jpg

hamstar
27-12-2004, 05:23 PM
i been thinking of doing this for a while too... tho mines alot simpler...

I blew a LED when connecting it to the 5v's on the usb tho...*scratches head*

dolby digital
28-12-2004, 04:47 PM
I had to buy a "fun" Christmas present and thought I would buy a DSE Christmas tree which you plug into the usb port and it lights up!! They had sold out

Codex
28-12-2004, 05:21 PM
I had to buy a "fun" Christmas present and thought I would buy a DSE Christmas tree which you plug into the usb port and it lights up!! They had sold out
lol u serious?? i mean they look so cheap lol well i guess its the xmas spirit that counts :xmouth: :dogeye:

dolby digital
28-12-2004, 09:00 PM
It was of those $5 pressie things... I was surprised they had all gone :o

Willuknight
28-12-2004, 09:38 PM
Also you can buy cheaper red LEDs from DSE.

They're actually brighter then what i used, and only about $2 each ! but you will need a different type of resistor.

8,000mcd Ultra Bright Red LED $5
http://www.dse.co.nz/cgi-bin/dse.storefront/41d12a3a003888da273fc0a87f9906ec/Product/View/Z4031

3,600mcd Super Bright Red LED $2
http://www.dse.co.nz/cgi-bin/dse.storefront/41d12a3a003888da273fc0a87f9906ec/Product/View/Z4074


i been thinking of doing this for a while too... tho mines alot simpler...

I blew a LED when connecting it to the 5v's on the usb tho...*scratches head*

You probably didn't have the right resistor. You need a resistor to limit the foltage going into the LED. Just ask at where you bought the LED, or at DSE what type of Resistor you need to limit the 5volt down to the led's level.

Willuknight
28-12-2004, 09:47 PM
Hardly seems worth the hassle when you can but one which looks a lot smarter and costs less

http://www.dansdata.com/usbthings.htm

http://www.dansdata.com/images/usbgadgets/rgblight800.jpg


Greg, those links are american, so they're like NZ$20. You can actually buy these things in NZ from pc shops, and trademe. Its about $9-$15 for the lower budget ones. Add in about $2.50 or $5 for postage, and my one is actually cheaper.

And if you use a cheaper LED its definately worth your time :D

dumbskate
30-03-2005, 02:54 PM
sorry to dig up old threads but i have a question for ya Willuknight

i want to use maybe 4 LED's to get the effect i want and was wondering, as i have forgotten 5th for physics if i will still need a resistor all will this use all 5 volts if i run them in paralle ???

chur cuz :thumbs:

godfather
30-03-2005, 03:14 PM
You must limit the LED current to below its maximum level. Typically 20 mA is used.

So each LED should have an appropriate resistor in series to limit the current. As LED's are not always all identical, paralleling them with one lower value resistor is not always succesful.

Resistor value (for DSE Z4031) is (Vusb - Vf LED) / 0.02 amps
= 5v-2.6v /0.02 = 120 ohms

Wattage is .02 x .02 x 120 = .048, so a standard miniature 0.125 or 0.25 watt 120 ohm resistor in each LED positive lead should be fine.

Total current = 4 x .02 = 0.08 amps (80 mA) and a standard USB port will deliver 500 mA. Should be OK.

Graham L
30-03-2005, 03:55 PM
The important thing to remember is that the forward voltage of the LED depends on the wavelength (colour). (I think Vf=1234/wavelength in nm). DSE catalogues have a page giving the voltages.

"White" LEDs are an exception because "white" doesn't have a wavelength. They are actually a blue LED, with a fair amount of UV, and there are phosphors included in the plastic encapsulation to produce the white light. They are "fluorescents" ;) Vf is 3.6 -4.2 depending on manufacturer.

For useful light, the 1W ones are quite impressive (and 3W and 5W even more so). Unfortunately they are still very expensive. You could run the 1W ones off USB ... 350mA current (at a bit over 3V for white). They need heatsinking, and current regulation.

You can buy the USB plugs from Jaycar. +5 is pin 1, gnd is pin 4.

But for a small torch I use the small ones with a number of high intensity white LEDs using 3 AAA cells. Much easier to carry than a computer. :)

godfather
30-03-2005, 04:36 PM
I agree Graham. I have several of the small 6 LED - 3 AAA cell ones around here. At $12 each they could not be built for the price.

Graham L
30-03-2005, 04:47 PM
I've even considered these torches as a source of cheap high intensity LEDs. But my only use for high intensity LEDs is in a torch ... :)

dumbskate
30-03-2005, 09:05 PM
thanx guyf for th useful info and all the calculations

the reason i am doing this is not for a light source but to dress up a cooling plate i am making for my laptop when it is at home. i wanted to place the LED's behind grooved perspec's sheeting to get the illumination effect.

so thanx again and im off

wintertide
30-03-2005, 09:40 PM
If you want a cheaper place to get the LED's from, leds.co.nz is a great place to find them - way cheaper than DSE at something like $2 per 15000mcd LED! :)