Lighting Help!

[Dem Pyros]

Ok, i have this new idea for my new computer i'm building. Of course i suck at electronics and modding so i'm hoping you guys could help.

Is there a way to hook up one or two cold cathode lights up to flash for hard drive activity?

[DaveW]

Cold Cathodes are not good for that-they need to warm up and cool down, so you can't really make them flash like this. LED's are what you need-a couple of superbright LED's will get the job done at the same price, and being smaller, will fit anywhere in your case. Hook them up to a power supply and use a small Transistor in line with the HDD activity header on your motherboard, and you're in the business.

You'll need the a resistor for your LED's, but it's not too complicated a circuit.

Try asking the guys in a local electronics shop, tell them you have a 5volt source and you want to run, say, 4 super brights to replace 2 cold cathodes, and tell them you want to hook them up to only be on when a binary high signal (at 5volts with next to no current) from a source external to the curcuit comes through via a transistor.

Or, print this off, and take it to them. They'll help you out. :) If they don't, i will.

-Dave

[dgrmkrp]

..or, use whatever lighting thingy you desire and.. this is where the electronics part start to go blurry.. (complicated, but not that much) either use an opto-transistor and a capacitor for a nice fade effect (the cold cathodes will work 'better' this way, cause you never get sudden transitions, but nice light-in and light-out effects.. with a hard drive that is heavily accessed you get a flickering light, but never complete darkness.. u can try removing the capacitor, for a nice flash effect, although the tubes wont go 100% unless you use special ones.. like the ones with fast response time they use in clubs and in photography).. linky to this is being looked for right now..

or do what dave said (i would go with this aproach too ..and maybe will) and use ultra bright leds.. in case u need some more details (seeing as i actually am studying this now for an exam i have..), i've done a lil drawing here :)

http://img219.imageshack.us/img219/695/tempcd6.jpg

..i think this is how the circuit should look like.. i'm doing some work on another circuit now, and i don't have a model for a LED built yet.. but i'm 90% sure this will do the job.. not only that, but instead of the motherboard signal, u should be able to use any signal :) dvd, lan, or other light pulse emitting device :)
also, for a 12V source u need a 470ohm resistor in series with the + of the LED, and with a 5V source something around 100ohm.. if i remeber correctly..
the transistor is acting like a switch.. only when the right amount of voltage activates it, will the switch 'switch' and allow the 5/12V to pass... in theory :)

the tip31c part i'm using does right that :) and my aplication does involve a 5V command signal... and a 12V exit :) so.. it should fit :)

hope i helped :)

[Dem Pyros]

So, i'm better off going with a bunch of LED's as compared to the cold cathodes to get a faster effect?

And would there be a risk of frying the motherboard?

[dgrmkrp]

hmm... well... LEDs can blink really fast.. they can blink so fast that some opto-transistors can't sense it anymore (had to do that experiment at a laboratory a few months back..).. and neither do our eyes.. the risk does exist.. now that you mention it.. but it's there in case something goes wrong.. hmm... you can a add a diode in series with the base of the transistor.. buy a 1n4007 diode from an electronics store, as this is a really common part.. it will bring down the command voltage by 0.6 or 0.7 volts, but it should still retain it's logical value of '1' (switch closed, current may pass). by adding this lil part you can insure that in case you manage to somehow push 5V or 12V from the psu in the mobo's header, this part won't allow it to pass, as it will be reverse biased... that is, current may flow only in one direction thru a diode.. and if you connect the diode such that the silver ring at one end is pointed towards the base of the transistor (doesn't have to be the middle pin, check the specification of the part at www.alldatasheet.com, or any other electronics part for that mater.. very helpful ;)), current can ony flow in the base, not the other way around, god forbid any accidents may happen :) make sure of this when you solder the circuit :)
any help needed, were here :)

[DaveW]

Double + Rep for dgrmkrp. Good work. :)

-Dave

[Dem Pyros]

Well, i suck with electronics.

These are going to be surrounding a window. Should i just buy some LED's, and then go to radioshack to ask about powering them with the 12v without blowing out the motherboard?

Is there a way to wire it so that the motherboard connector isn't directly in line with the power?

[dgrmkrp]

Is there a way to wire it so that the motherboard connector isn't directly in line with the power?
well... it isn't if you watch the schematic closely :) it's perpendicular :) and believe it or not, this simplified schematic is used in every processor and chip out there.. at least the principle: when you wanna control something, do it with transistors :)

..with the diode installed correctly, there is close to 0 probability to damage anything.. just go to a shop and buy the stuff.. consult with the guy there :) show him the schematic :) and if u need guidance in actually making the circuit, we'll help :) i can even do some renderings of a mock board (but not now, i have to learn maths again.. exam coming.. i think i have 3 next week.. so next week, in a learning break) and some steps to take to install stuff :) just make sure you can solder ;)

[Dem Pyros]

thank you very much for all of your help!

[Doomfest]

I have an idea. Instead of cold cathodes, why not try this: http://xoxide.com/sunbeam-meteor-light-blue.html It seems like it's simple enough.

P.S. Something simple, like a relay connected to the HD LED pin on the motherboard and the power switch leads will give you the effect, i think.

[slytherock]

I have an idea. Instead of cold cathodes, why not try this: http://xoxide.com/sunbeam-meteor-light-blue.html It seems like it's simple enough.

P.S. Something simple, like a relay connected to the HD LED pin on the motherboard and the power switch leads will give you the effect, i think.
Those leds are nice, but they dont bright very much...

On the next pic, (ok, I must say that I overload this box of light...) on the bottom front I have 2 of those where 2 80mm led fans stand...
http://img.photobucket.com/albums/v68/slytherock/total000a.jpg

[dgrmkrp]

meteor lights are perfect :) big as a ccfl yet still leds :) has it's own blinking module too.. but it does stray away from 'hdd controlled'.. as with the warning that comes with variable speed fans: don't connect them to another controller unless u set it at full speed.. ;)

errm.. the circuit above acts as a relay.. both gives away all mechanical parts (that's what a relay is: an electro-magnetic mechanical lock.. when current passes thru it's windings, an electro-magnet is activated and it makes a piece of metal move, therefore making contact with another piece).. this idea is taken further with transistors: when voltage is applied to the 'base' it creates a difference of carriers density >> makes the electrons go one way or another and achieves a sort of a tunnel (depends on materials and needs and etc).. when this tunnel is formed by a big enough voltage, current may pass 'freely' and u get the same 'click' like in relays, but with no moving parts (and it be hard to hear;)).. you could use a relay, sure, but you severely diminish the response potential: relays are slower.. you can't build a cpu (although i saw some nice machines doing basic task.. big thing, not very fast, and exceptionally good-looking IMH, close to art rather than real-life application) or extensive logic with relays.. mainly because of size too.. electronics are easier to hide.. or show.. well, actually, if u could show it, it wouldn't be a rather bad idea :) think of the small valves in one of cooler master's products.. they show it thru a nice window.. old tech is still pretty fashionable (relays are not old, but in this case, you would be reverting to them).. but if u connect a relay in your case to a source that will make it active again and again and again >> more noise and maybe mechanical failure.. i would stick with the fully 'electronic relay' for this application :) oh, one other thing.. a relay doesn't need a heat sink :P (the transistor may need one if the load is big enough)
happy modding.. i'm going to sleep now :bunny:

edit: oh.. forgot about brightness.. and the post above.. well, doesn't matter what you connect :) just remember that if u go with leds you should add those resistors depending on voltage.. go with 5V for safety this time.. and if you get more accustomed to the way this works, you can add any load (we'll call the load everything that follows after the transistor:)) by changing only the heatsink to suit a higher power.. up to a point, but if we are talking lights here.. you can have your way with this.. throw in a fuse (something in the lines of 3-4A at 12V) before the 5/12V entering the transistor for safety, in case you load it with lots of stuff of course, put a bad-ass heat sink on it (you can buy it from the shop too.. you need one, if it's small) - cause it looks good to go overboard sometimes - and make this a feature :) your very own, home made, pc-part :)

[Doomfest]

Well, I'm sure there's an alternative to using relays.

[slytherock]

Well, I'm sure there's an alternative to using relays.

Relay are not really hard to use, and are pretty safe... I'll go with them...

[Dem Pyros]

I'm going with the LED's.

So basically a relay with a diode, some resistors and a fuse?

[dgrmkrp]

sure, but be careful as.. well, relays need just a current passing, so they aren't polarized >> much much easier.. in case the relay doesn't have enough punch, remove the diode (like i said, it gobbles up precious voltage, but gives you more safety).
again, relays make a noise when they work... they might be easier to use, but u should take care about the noise factor.. maybe it will be killed by the fans, but in a silent system this will surely become the loudest noise source.. think of it as a hard drive noise amplifier :) i'm not sure how to silence a relay... now there is something to think about =)

[Doomfest]

Silencing a relay...Wrap it in anti-noise foam? Put another box around it? Both?

or go crazy and suspend it inside a vacuum box, suspended only by some thin pieces of wire. Noise can't pass where there are no particles :3