Screen light question

[peepboon]

Hi guys

My first post on here, so sorry if its in the wrong section.

Basically, I would like to light the back of my LCD screen with some cold cathodes BUT I am using a laptop (going to uni and need the space). Is there such things as mains powered cold cathodes or even USB ones? If so, please can you post some links, etc...if it helps, I am based in the UK.

Also...there are some crazy stuff on here that I never thought possible!

Pete

Also, thanks in advance!

[Spawn-Inc]

Welcome to the forums!

so do you mean for looks? or your lcd CCFL broke? i don't think i've ever seen a usb CCFL kit. if you want lighting i would go with some LED's since they use less power.

LED strip of lights. (http://www.performance-pcs.com/catalog/index.php?main_page=product_info&cPath=95&products_id=791)

[Air Cooling Fan]

Sounds good, I think.

If the cathodes are actually going to light the screen, won't you end up with a weird purple/red/blue/green or yellow back lit screen?

Might look cool to show off, but I'm not sure it'd be usuable.

Anyway, I found this link (http://forums.bit-tech.net/showthread.php?t=89344)

That's getting a USB device to power from a PSU, but I'm pretty sure you can do the process in reverse, and mod the molex connector on a CCFL to a usb cable for power.

[Luke122]

That's getting a USB device to power from a PSU, but I'm pretty sure you can do the process in reverse, and mod the molex connector on a CCFL to a usb cable for power.

I dont think that you can.. USB only supplies 5v, and if I'm not mistaken a ccfl takes 12v to light up.

My understanding of the OP's request is that he wants to light up the backside of his LCD (the lid) on his laptop, not replace the backlight. I could be mistaken though...

Either way, LED's are the way to go. They draw very little power, take up almost no space, and you can grab power for them from the power going to the inverter in the screen. Make sure you use proper resistors, and the LED's will outlive the laptop! :D

***Be very VERY careful opening the screen on a laptop, as the ribbon cables are very delicate, and can tear, leaving you with a nice expensive paperweight. ***

[Spawn-Inc]

i wouldn't want to run 12v through those tiny wires from the usb. and 5v won't be enough to power a CCFL like said above. but you could do take a usb exstension (http://www.newegg.com/Product/Product.aspx?Item=N82E16812105707) cord then attach a string of LED's with resistors and wire it up to the red and black wire for 5v. then you can just plug it into your laptop.

[Air Cooling Fan]

I dont think that you can.. USB only supplies 5v, and if I'm not mistaken a ccfl takes 12v to light up.

Ok, I stand corrected. Though the technique would still be OK for LEDS I suppose? Drawing power from the screen light, as you suggest would be much neater, it might be a more difficult mod depending on how they're wired in.

Modding the lid of the laptop sounds great, very cool. I stand corrected on that too.

[Luke122]

I've seen macbooks where the apple logo on the front was custom backlit using LED's.. looks very pimp. :D

[Spawn-Inc]

I've seen macbooks where the apple logo on the front was custom backlit using LED's.. looks very pimp. :D

isn't that stock?



Ok, I stand corrected. Though the technique would still be OK for LEDS I suppose? Drawing power from the screen light, as you suggest would be much neater, it might be a more difficult mod depending on how they're wired in.

Modding the lid of the laptop sounds great, very cool. I stand corrected on that too.


ya the tutorial you posted ACF was for 5v molex items only. the yellow wire is 12v.

[Luke122]

isn't that stock?


Not on the older ones.. plus it's the lcd backlight that lights up the current ones, so slipping in a colored film would make it light up in other colors. :D

[peepboon]

firstly, thanks sooo muh for all the replies.

Sory if I didn't make myself clear - I want to light the back of the screen, to give a blue aura around the screen.

Due to th nature of using a laptop, I'm not too sure how I would go about to power up the cathodes or LEDs.

Pete

[Luke122]

Ok, that makes it much easier.

If you want to put the LEDs INSIDE the laptop screen, you need to tap into the power for the screen, and have somewhere for the light to come out.

From what I understand though, you want to have the lights outside the lid, but behind it so that when you are working on the laptop, there is a glow from behind the screen.

What you need are some LED's, a scrap USB cable (to cut) and some resistors. Most ultrabright LEDs are either 20 or 30mA, so make sure you find out which yours are. A USB port gives 5v, so cut the cable to the right length, and isolate the Red and Black wires. Cut the rest off, and tape them up to prevent shorting.

Connect the LED's flat side (negative) to the resistor, and then connect the resistor to the black wire. Connect the red wire to the round side (positive) of the LED, and plug it in.

Depending on the number of LEDs you use, and the specs on them, you can calculate the resistors you need using this calculator. (http://led.linear1.org/led.wiz)

[Spawn-Inc]

beat me to it... ohwell.

that pretty much sums it all up. if you need LED's cheap then try Lsdiodes (http://www.lsdiodes.com/), 45 cent LEDs! - $2 shipping to anywhere in the world!

[peepboon]

guys, u are numero uno...luckily I did electronics so hopefully making it wont be too hard, lol thanks sooo much guys!