making a LED strip... need help from u experts

[Nismo]

im planning on making a LED strip for my computer. But im not sure where to begin since im a noob working with LEDs. Can you guys help me out or find a tutorial or something that shows how to make a LED strip. I got couple hundred of blue LEDS waiting. So far all i know is i will need some sort of long , thin pcb and a bit of soldering. And does anyone know where they sell plastic tubes like the ones neons and ccfl use or are these not available to us. This little project sounds really interesting and fun for me. But i dont know where to start :( . Thanks you in advance.

[magick_man]

http://tinypic.com/bp82

[Nismo]

thanks for your input but i was thinking of hooking up like 20-30 leds in one strip using pcb or something. Not too sure how to solder circuits on pcb.

[Viper2004]

Hmm, I dunno maybe its not possibly to make ONE strip of 20 leds. Maybe you have to make a couple strips, like the one in magik_man's picture.

[cack01]

You will need to make them in parallel. You can do a series circuit (pictured earlier) and make a couple of strips but wiring them in parallel would be better.
http://www.theledlight.com/ledcircuits.html (Shows the difference)

[magick_man]

well yeah i guess you could do it that way too,
:)

~Magick_Man~

[Nismo]

thanks guys for the input

[ares350]

cant do 20 in a series, but you can do 5 series of 4 to total 20, and mount them one after the other.

I got these surface mount thingies, they let you mount the LED nicely in any flat surface(ex. a square tube cut in half, mount LEDs, seal back together, all wiring and whatnot is concealed with a nice esposed line of LEDs.

that will hide the 5 runs of wires you need to make for the 5 series.

[CheeZeTM]

i have experience with PCB LEDS ohms law etc etc etc wouldnt mind helping you out with your project

i drew a schematic of what i would do on a PCB if you are interested i can give u some better instructions, teach u how to soldier, etc.. if you can, u can contact me on AIM or yahoo IM
jamrf1234 aol
jamrf Yahoo

email is jamrf@emai.com

Let me know

[CheeZeTM]

schematic

[toyomatt84]

It looks like it'll work to me, but I'm no electrician.

[CheeZeTM]

it's a hobby pretty ****ty schematic, my actual work looks better, home-makeing PCB's with my own traces

[PCGUY112887]

Well sorry to kick this up but I got this same bright idea last night....
What if you were to use a wall socket? 120v, would amps matter? I don't think so because in the pages I saw above it just said "12v source". Well if I had 35 3.5v led's, then I could make a strip of 35 ultra bright blue LED's :)

I read about useing PCB, but where can you even buy PCB? I know radio shack has some.. but it's small and EXPENSIVE. Also how would you connect all of these led's to it? I know how to solder and my friend is even better at it... but I am having a hard time pictureing it in my head.

[PCGUY112887]

Humm this would look like it would work better.. still dunno what the resistor's would be for.
http://www.lsdiodes.com/tutorial/jpg/parallel101.jpg

[Dc5e]

pcguy, the 120v outlet sockets are AC, it wouldn't work with the LEDs. Anyways one way is just hooking up the LED's in parallel, but each LED strip has 4 so it will be able to handle the 12v. So basically you'd be hooking up the LED's in multiples of 4 with as many strips as you want.

Its similar to pcguy's picture, but each LED represents 4 LEDs and the battery is 12v (from computer powersupply) instead of 3v shown on the diagram.

also, out of curiosity, where'd you get all those blue led's and how much did you pay for them? because when i've looked at them they're not cheap... unless you spent alot

[PCGUY112887]

Woops I forgot to edit out the outlet idea :P
And there is a sticky here on links to buy LED's.. 100 would run you about $20-$25.

[DeViL_909]

Ebay has a lot of LEDs that are pretty good quality. Check on there. Also you could buy 5v LEDs and run them in paralel on your 5v rail. They would all get the 5v needed and you could stack the 20 on there as long as you have a fairly decent power suply. LEDs really don't use much power so you should be fine. Anyone think that all those on one rail would hurt anything? Also you could use acrylic tubing to place them in and then frost the outside to disperse the light better.

[PCGUY112887]

If running on a paralel is so simple why don't more people do it? I mean insted of useing 3v led's and put 4 of them on a 12v rail why not be able to use a bunch of 5v?

It's also easier to wire...

[DeViL_909]

Beats me, but chances are that I am off my rocker and my idea may not work. I have hooked up a few leds like this, but never as many as you have your mind set on. I would wait and see what some more experienced members have to say about it.

[grimm003]

I wouldnt put that many to my power supply, the PC is touchy with voltage so I just wouldnt take the risk. But an idea is u can take the power cord from an old nes/sega/ps2 whatever and cut off the one end and use that as a 12V DC source

[Nismo]

also, out of curiosity, where'd you get all those blue led's and how much did you pay for them? because when i've looked at them they're not cheap... unless you spent alot

i got these leds for very cheap , i think it was ~20$ for like 200-300. Good quality too.

Well i got another question for you guys. where do you get the thin , long pcbs or anything that holds the leds in place. All i can find is square pcbs or large retangle ones. I want ones that are about 1" in width. Also is there such thing as round, tube acrylic. Like the ones used for neons , and ccfls.
thanks guys

[shard]

cant yu cut the PCB? that might do what you need

[zexmarquies01]

this here is just a basic Paint image i made.

its pretty crappy. but it shows ya how to hook LEDS in a parallel Circut.

I'll also make another one, if you want to see how to make them in a Series/parallel Circut, but doing the math on that, requires a bit more work. But its still not hard at all. just have to know how to add/multiply, and divide. OHM's law isn't hard by any means.

[zexmarquies01]

also, something to note.

If he uses a 12 Volt power source, even in a parallel Circuit, that might be to much voltage for each LED. he could end up blowing them. and blue LED's arn't cheap.

also, the LED's that you have. what Voltage are they? i forget already, if it was said or not.

On a 12v. source, with the voltage of the LED's, we might be able to figure out how many you can safely put on a strip.

[zexmarquies01]

i just figured...

that on a 12. volt power source, according to voltage only, you would be able to fit about 14 3.5 volt LED's, in a parallel Circuit.........i think...

someone might want to check my math for me.

if each LED uses 3.5 volts. in parallel, two of them should use 1.75 volts. take 12 divide it by 1.75, you get a number thats like...6.8'ish. But you can round that up to 7. it shouldn't effect the brightness to much, better than giving them To much voltage, because you can then burn them out.

And if that answer is 7, then multiply that by 2. because 2 LED's make 1.75V. giving you about 14 LED's per strip, on a 12v. Power source.

does that sound abour right people?

EDIT: Oh crap....wait a minute.....i think i might have messed up here. This is for finding RESISTANCE. er...nevermind...i don't think what i said will work out.....sorry.

[DeViL_909]

Well lets think about this. How many things in your comp run on paralel? Many people connect HDs this way, or Optical drives. I am pretty sure that you can connect a fair number or LEDs together considering the fact that they use so little power to begin with. I think you would have to have a ungodly amount of them to put a hurting on your PSU.

[zexmarquies01]

well forgetting all the math crap i said earlier, since that applies to resistance....

But, you can also do this too. make a series parallel Circuit, on a strip of a PC board.

you could do this, to shorten up your led strip, or just plane put more LED's on it, without making the strip to long.

[Black_Ops]

hey just a FYI LEDs work fine on either AC or DC just so you know

120vac ----->|--/\/\/\/---| resistor being 6k ohms for a 2.1v led at 20ma
neutral ------------------| Led can go in either way bacuse it dosent matter for AC

[zexmarquies01]

hey blackops, i just looked at yoru picture you made..

Is that in series or parallel?

if its in parallel, shouldn't the reistor be BEFORE the led?

[Black_Ops]

hey blackops, i just looked at yoru picture you made..

Is that in series or parallel?

if its in parallel, shouldn't the reistor be BEFORE the led?

ummm its ASCII for a single led, an a single resistor across the 120 AC line

[Hamspiced]

its possible iv emade a 27led strip for an Amp box hooked to my car a year ago... ill find the how-to i wrote and post it.....

[PCGUY112887]

:) thx

[Hamspiced]

I wrote this for a couple forums i frequent a while back, i hope this helps:


Materials needed:

1 LED (Light Emitting Diode)
Two small wires (optional)
Resistor (size varies)


LED's
-------------------

Ok, to start off with you need to know what the Specs of your LED are. If you do not knwo there is absolutly no way to know because they are not marked or identified according to wattage etc.

Some LEDs have a built in resistor and those can be plugged right into any 12v source. however those that do not have inline Resistors require a resistor.


Once you have your LED(s)

They should come with or be provided a Specifications Sheet.


Ohms Law
-------------------------

The specs are generally as followed.

Luminous Intensity= MCD:2500Typical/3000MAX
Reverse Voltage: 5.0v
DC Forward Voltage: 3.3v Typical
DC Forward Current: 20~30mA
Viewing Angle +/-10*
Lead soldering temp is generally 260*C for 5 Sec.



Now you need to learn about Ohms Law....

First i will give you Ohms Variables...

# = Number of LED's Used
led = Amps LED needs to operate or Forward current
RS = Ohms (Resistance) needed
+V = Imput Voltage
VLed = Voltage LED is rated at (Reverse Voltage)

Now ill show you Ohms law




Rs = [+V - (Vled)] / (# x led)


Or


+V - (vled)
------------ = Rs
# x led



Ohms law is used to find the resistance needed to make an electrical application work... Since we are using a RAW LED chances are the input volt used is much more then the LED can handle..


Application
--------------------

So lets say we are using this LED in a Car. The cars battery is supposed to be 12v but due to alternator current we will say that it will operate at an average of 13.45v

so lets apply our variables..


RS = ?
# = 1
led = 20~30ma so tha twill be .02~.03 so it can accept anywhere between there, so well pic .02
+V = 13.45
Vled = 5v

lets plug this into Ohms law

(13.45 - 5) / (1 x .02)

(8.45)/(.02)

422.5Ohms

So we would need one or more Resistors that can equal up to 422 or so Ohms.



Resistors
-----------------

Resistors can be wired two different ways... In a series or in parellel. i will show a description of each

- Series -

where you would wire the Resistor side to side similar to:

+ = Positive Wire
- = Negative wire

___+______(-)
__+_+_____(-)
_+____+___(-)
+______+__(-)
+Resistor+__(-)
+_______+__(-)
+Resistor+__(-)
+______+___(-)
_+____+____(-)
__+_+______(-)
___+_______(-)


When you wire something in a series the resistance of the Resistor is cut in half per resister you use so...

say we are using 2 resistors that are 300Ohms of resistance each wired in parallel that means we would be using 300 Ohms of resistance (300/2 = 150 each 2 resisters @ 150ohms = 300)
if we were using 3 resistors origionally rated at 300ohms wired in a series we would have 450 ohms of resistance (300/2 = 150 x 3 = 450 )

-Parallel-


A set of resistors wired in parallel means that the resistors are wired end to end such as :


++++<RESISTOR>+<RESISTOR>+++++++
(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)(-)

Resistors wired in parallel ADD their resistances to each other... so if we had two 300ohm resistors wired in parallel that means they are now 500 ohms total.. or if we had one 30ohm and one 50ohm resistor we are creating 80ohms of resistance.

note: Resistors are Dualpolor so they can be used on either Positive or Negative wires. I personally choose positive but thats me.


Multiple LED's
------------------

To wire Multiple LED's you need to firs figure out how many to use, then how you want to wire them, parallel or in a series.. the most effective way is to wirethem in Parrallel because this way if one goes out you only need to replace the one.

you use the same law of Ohms, however you change the numerator to match the number of LED's you are using (you increase the # variable)




If anyone needs any help on how to do this please feel free to ask and never hesitate. i have sucessfully made a 27 LED Lightbar for my Amp Box using this formula.

http://images.cardomain.com/member_images/7/web/295000-295999/295156_21_full.jpg
http://images.cardomain.com/member_images/7/web/295000-295999/295156_22_full.jpg



Advantages of LED's over NEON or standard lights
--------------------------------------------------------------

Unlike standard light bulbs LEDs have a very thick filiment and instead of BURNING a filiment they adjust the frequency that the filiment is charged with to direct the actual light emitted, so the lifespan of it is increased tremendously....

Unlike a NEON bar LED's require no load time or Charge time. NEONS require the particles of gas to be charged for them to operate correctly and often that can take a few seconds to at max a minute. Leds can be turned on and off instantly.

Additionally Neons are EXTREMELY fragile. LEDs are usually encased with a very thick hardplastic shell which makes them resistance to almost any impact.


Types of LED's
-----------------------
Leds come in THOUSANDS of colors, litterally. Depending on which you chose tehir wavelengths can differ indefinatly. some common colors are:

Blue
Light Blue
Dark Red
Red
Pink
Orange
Green
Purple
Tan
Yellow
Black(UV)
White
Ultra White Light

the list can go on indefinatly


I just made a LED Flashlight using 2 Ultra Bright White LED's which makes it absolutly excellent for engine work.


Good luck guys (and girls), id love to hear some stoies if ive helped.

-Hamspiced

[Nismo]

hamsplice , nice guide , very helpful since i have decided to do some LED strips in the car now and thanks everyone for your input. What were the materials you used to make the LED Strip. Just wires, resistor and leds? Did you use a soild piece to attach the LEDS?

edit

hey , i have always wondered how to make a LED flash light. Can you show me how and material needed. I got some white 3mm LEDS too. Sounds fun :)

[Hamspiced]

well when i made the strip i actually got a piece of thick poster paper and i drew a line down the middle, then two lines on either side about 1/8th apart..


--------------------- >1/8th inch
================
---------------------

then at one half inch marks i put holes on either side

-------+--------+------ >1/8th inch
================
-------+--------+------

and id put my LED in there across the gap

-------+--------+------ >1/8th inch
=====LED====LED ==
-------+--------+------

if you catch my drift. Then i used wires on the other side and went down the entire strip

At the end of the strip i put the proper resistors that i would of needed.

Heres an Ms Paint drawing representing what i mean

http://s92002946.onlinehome.us/Pictures/SAVE/LED%20Light%20Bar%202.gif

Red is obviously the (+) current which on most or all LEDs is the longer wire.

ill make a quick mockup of a LED strip when i have time tomorrow and take pictures to show you.



LED Flashlight...

First follow my howto to find out what your LED resistance is, then get your resistors,... it doresnt really matter how you wire it up, as long as you have the proper resistance. if its a standard flashligh with 2 AA's it will only require around 3volts max. if you use too high a resistor the light will be very dim. if you use too low the light will be bright, burn out the resistor, or the LED... if you ever burnt an LED out youll know that its the nastiest smell on earth.

when i made my flashlight i basically shoved three LEDS together, used paper to separate the (-) from the (+) current and found a resistor, i packed it in the flashlight and it worked great. if you have any questions feel free to talk to me on AIM or send me an E-mail.

I made the howto for 3 different forums and 2 mods form each forum put it in a special How To page ;)