I don't know if I'll do a tutorial on this one as well.. but I certainly have enough photos of every stage of this one.

As far as the LED's being pulsed, I dunno. I just assumed you needed strobe/flash lights, I didn't know LED's could be used.

The color balancing will be tweaked when I find out how 'blue' it really is. Like I said this thing is just a $90.00 paper weight right now. I don't have a camera to test it on, hence all the photos are of it in my hand. LOL

Put a dimmer on it instead of a switch so you can control how much light comes out.

Stop telling me what to do all the time!
Oh so check this out, I go to the Electronis store. AndI've eben talked to a few guys here on GFY about this light thing as a direct result of this thread. They all agree that LEDs can NOT be dimmed.

"It's digital, it's either on or off, there is no dim"

I went to EVS today t pick up soame tapes and I saw one of their super-expensive panel lights which made up of about 200 LEDs. And, IT DIMS!

It's not a smooth dim, but it steps down in stages. Like maybe 10 steps from 100% down to 0%.

HOW IS THAT POSSIBLE???

LEDs can certainly be dimmed, just vary the current. That's why I asked earlier about the value of the resistor you used and whether you were satisfied with the light output.

Looks like you're using 240 ohms, which at 2 x 3.5V forward drop would work out to roughly 8mA of current. Check the specs to be sure, but it's likely the ones you have can tolerate more than double that. To limit the current to 20mA for the two LEDs in series with a 9V source you'd use a 100 ohm resistor.

To add dimming to your existing light just put a wire wound potentiometer in the "+" line between the battery and the array, say 1000 ohms. It needs to be wire wound (5 watts) because I don't think a standard pot would handle that current.

Oh yeah, some pots have an on/off switch built into them - when the pot is at minimum it clicks to off. Not sure if you can get them in wirewound, but that may help you save a bit of space.

Cool, thanks Rowan, I'm my way to ElectronicCity RIGHT NOW!

Well... shit. I just went to Electronic City and they said I'd fry a 1K potentiometer. So I showed him my post-it note (from Rowan's post) and he agreed I'd need a 5 watt potentiometer. He said he didn't carry anything that big. :(

Jeses, it must look like a dimmer switch from a wall outlet.

Either way... now I'm on a fucking mission. GET A DIMMER!!! :)
When he saw I had "40 whites" in the light he went "40 whites? WHOA!" LOL.

RedShoe, Its hard to track the thread back and read lot of different opinions and so.

Why are you using 80 resisters? you know each resister would dissipate some power in form of heat and in turn will consume more battery?

You said you are using second method of rowan's drawing to connect LEDs, thats what I suggested.

But, when you connect 3-4 LEDs in series and attach to 9v battery you don't need the resister. The resister rowan showed is just because you are using two LEDs.

And I don't think anyone can say not to connect in parallel, whatever type of circuit it is. We always connect them parallel when we need to consume one source.
Just like, tube light, bulb and fan in your room are connected parallel to your main power supply.

Electronics is really very simple, you only need to learn 2-3 simple things.

* Ohm's Law
* Effect of series connected resisters and/or bulbs (LEDs whatever)
* Effect of parallel connected resisters and/or bulbs (LEDs whatever)

And the hobby you own is simply loveable. Why you are not into Engineering?

I was suggesting this way:


http://img143.imageshack.us/img143/8...ingledssk5.jpg

Hey RedShoe, been watching your project with some interest. Nice one!

I know you're pretty much already done with your project, but if I may make a recommendation?

You might find that a few Luxor LEDs are what you're chasing. They go up to 5W [yes, 5W LEDs] - and their 3Ws are very bright, with a very reasonable power consumption [3AAAs will power them for 25+ hours on full bright]

Everyone is telling you different stories because there are definitely multiple ways to do these things.

Generally speaking though, hooking each LED [esp high consuptions ones such as the whites] to a battery is NOT the optimal solution - most SHOULD have a driver circuit to ensure steady current is delivered. If you can't control the current, you'll burn the LEDs out.

These will not only
a] prolong battery and LED life, but
b] provide maximum brightness off much smaller power supply

Links:
http://www.satcure-focus.com/tutor/page10.htm
http://www.luxeonstar.com/faq.php

Google for luxeon drivers or LED drivers, and you'll find plenty of people have gone where you have before.

I figure if you went to so much effort to make a great device, go the whole way! With a decet driver, you'll have dimming control, and a much cheaper and cleaner system.

I suggested Luxeon LEDs when he did his first on-camera lamp using LED "torch globe" assemblies, but he didn't wanna know about it :)

lol .. he already have messed up his existing knowledge.

hey rowan, any comments about my config? see fig. on first page.

intresting...

RedShow, where did you get that black round frame? I'd be very interrested by one!!

The point that a bunch of you seem to miss is that white leds need to be CURRENT limited, not voltage limited.

http://upload.wikimedia.org/wikipedi...200px-Ohm3.gif

Ohm looks like one cranky motherfucker. I guess he spent too much time dealing with gfy variety morons.

Dude..

http://upload.wikimedia.org/wikipedi...rovementS4.jpg

That's right.. you don't have a clue. Stick to PHP-CODER-FOR-HIRE-ing or whatever it is you waste your life on.

Rowan seems to be the only one talking sense... and no, quoting him with thumbs up doesn't make you smart as well. I guess sheep follow the shepherd.

Hope you payed attention to this one RedShoe :)

http://thsrv.com/p/leds.gif

pay attention son, it's a drainage ditch overflow pipe. I just got it at the hardware store. It's just a basic run of the mill, 4" abs pipe drain hole cover. Nothing more. I just cut it with a saw and sanded it to fit.

I'll reply to the other posts (Vick and Rowan) when I get back.

80 resistors? No. I mean I drilled 80 holes, put in 40 LEDs, and used 20 resistors.1 resistor per 2 LEDs




Engineering? ME!?!?! LOL. I'm a Super Genius, I'm not smart.

You're wrong bro. I looked this shit up right after you posted it and my next one for Tony404, even though he REFUSES to just simply ask for it... It's like that scene in fight club when Ed Norton is hinting that he needs a place to stay and Brad Pitt says "all you gotta do is ask man." and Ed says, "really? would that be a problem? and Brad Pitt says, "Would it be a problem for you to ask?"

I've told Tony we could "work something out" so we'll see. But yeah I really wann use those 5W Luxeons on the next one, but I MUST have a way to tone it down. They would wash out and blow thru anything indoors. I want to light up a pussy, not make it so bright that it blinds you.

The next one will be more universal. I'm going to make fit almost any DVX. The first one only fit my specific wide angle and this one only fits a specific wide angle as well.

The problem with the Luxeons is their footprint. They are like the size of a quarter. That sort of defeats the purpose of using LEDs. I use LEDs because they are so small.

Thanks Quantum-X. Thanks for the links. And yeah I definitly want to do it right. Once I get a decent prototype, I'm going to send to my friend that has a CnC machine and have him cut one out of Delrin and really do it up right. I'm going to have him cut in the battery ports as well. I've been toying with the idea of putting a battery pack inside and then just making it chargeable.

The Drivers are definitly the next step in my evolution to becoming the next on camera lighting designer catering to the adult industry... person.

What kind of camera do you shoot with?

5Ws are probably overkill. I explore w/ a 3W on my headtorch, and it is very, very bright, and very, very decent. You could probably get away with a couple of 1Ws. If you're down for a challenge, use the 1Ws w/ drivers operating on alternate cycles, that is, when you dim them visa pulsing, when one batch of LEDs is offer, the other is on, to ensure you've got a steady fill..

I shoot w/ a 1Ds.

And you are going to listen to those guys? What do they know about BUILDING ring lights? Come on!

Or...

Suck it up and by the Kinoflo ring light like the big boys have. The down side to that is that it's kind of big and the models kick it when you come in too close for a shot. And IT can be dimmed... oh yes, it can be dimmed. Just make sure to get the right color temp to match your other lights.

Next time you are in Evs, kick one of those queens in the nuts for me. They were supposed to send me a bulb for a Rifa light and didn't. :321GFY

Call EVS, what am I an EVS rep? I was just in there yesterday actually.

I know there is a Kino light. But how am I going to start a small side business where I can compete with them if all I do just buy it?

You don't go to Ford and say, "Just go buy a Honda." Do you?

I know they make computer cases as well, but I'll never buy one. I'm a builder. I build things. It's a gift... and a curse.

:1orglaugh :1orglaugh

you are so damn idiot :winkwink:


Do you really think what u just said? We don't need to limit voltage across a damn white LED?

I mean, Is it OK to apply 220 volts across it? ROLF :1orglaugh :1orglaugh :1orglaugh

And for the second part of your statement, we do not normally limit the current in a circuit (LED) in this case. We just apply appropriate voltage and the circuit (LED) draws current according to its internal resistance.

We ONLY limit the current where we think a short circuit can happen and cause fire, like in houses and offices and we use circuit breaker for that. Its like a fuse, which limit the current up to a certain level.

Right, 1 resister per 2 LEDs, and those LEDs are in series? If yes, why don't you put another LED in series with 2 and eliminate the resister?

Or those LEDs were in parallel?

220 volts? :uhoh

lolz, yes according to quantum-x -- He said we don't need to voltage limit the white LEDs.

Well pretty sure you wont get 220 volts dc from any battery pack. You only need to limit voltage if there is voltage there to limit.

of course.

And in this case, battery is 9v and we need to limit the voltage to ~3v so that LED don't get fucked.

just so you guys know. Hooking up a 9v to a bright white LED will fry it in less than 2 seconds. It makes a pretty little "POP" sound when it dies.

Exactly. It does mean that voltage need to be limited for white (and all) LEDs.

Not the voltage, the current! Limit the CURRENT! :)

No, we put resistor in series with LED to drop some voltage across resister, this way we limit voltage across LED.

Well, my point was : You need the right voltage on each LED, and limit the current going trough them :)

I understand what you mean. But mate, when we say 'right' voltage -- Its mean we are limiting the voltage to a certain level which do not harm the circuit (LED). As long as concern to limit the current, we do not limit. It get limited on its own depending on the internal resistance of the circuit (LED).


For example, attach two batteries of 1.5 volts each to make 3 volts, right? Then attach an LED to it, LED will be ON.

Did we limit the current? No, current is automatically remain within limit of approx 15-20mA due to the internal resistance.


Ohm's Law comes here, at constant resistance current and voltage are directly proportional. So, limiting voltage is actually limiting current as well.
You are also right in one way. But again, to limit the current we actually limit voltage, assuming resistance is constant.

boys, boys, boys... can't we just put our differences aside and do some good for the greater common of the industry?



LOL

Vick, I'm not quite getting the "no resistor" thing. Internal resistance of what - the battery?

Well, If we connect 3 LEDs of 3v each in series with a 9v battery. Do we need resistor?

I understand what you're saying, I just don't understand how it works. With every fraction of a volt above the combined forward voltage of the LED string, surely the dissipation will increase remarkably?

I know that those keychain torch LEDs don't usually have a resistor, but that's because the button cell batteries cannot supply more current than the LEDs can tolerate. A short circuited 9V battery would probably be able to push out more than 30mA...

If the forward voltage of each LED was (say) 2.8V and the battery puts out exactly 9V then the difference is 0.6V, and to stay at 30mA you'd need 22 ohms of series resistance. Surely a battery does not have such a high internal resistance?