driving your LED(No resistors allowed)? Read this

[xwingband]

I've seen so many questions on drivers and can they run this... what setting can they use...

Here's the skinny: The drivers we use are constant current, meaning the voltage changing (batteries draining) doesn't matter all that much.

A consequence of this is you are free to use whatever batteries you want within reason.

Now the meat of why I wanted to post this... settings. The CF and Ultraboard allow you to change the current to the LED! So when you look at the LED forget the voltage!

"Can I run _______?" Is irrelevant! If it's an LED and you match the current volts don't matter.

Example: Ultraboard has four settings: V , III Blue/White/Green , K2 , III Red and Amber

THIS REALLY MEANS: 700mA, 1000mA, 1500mA, 1540mA

So if your LED wants 1000mA you can select the III Blue/White/Green setting. Even if it needs 7V it'll drive it. If your LED has a target of 700mA you can overdrive it at 1000mAh. So a V would be overdriven on the III Blue/White/Green setting.

[LAN-ED-TUL]

so a V would be overdriven on a US board by 300 mA then, right X? is that not enough to worry bout damage to the LV led? just wondered.

[Do-Clo]

so a V would be overdriven on a US board by 300 mA then, right X? is that not enough to worry bout damage to the LV led? just wondered.

The ultra sound board has a setting for the Lux V which drives it at 700ma

[acerocket]

Ask Corbin. The Killer Penny is running a Lux V from one of his driver boards at 1000 mA. As far as I know, it's still going.

[Luar Selbor]

So if i put 8 aaa in a saber and put a Lux III. The Lux III will not fry. Because i would like to use both III and V on a CF.

[xwingband]

Overdriving is okay... within reason. Take a White III to 2 amps it will do funny things to the tint! If your LED and heatsink can handle it then you'll only loss life on the LED (a few thousand off a already 70,000 hour typical life).

Luar, 8AAA of rechargeables is 9.6V... that'd be cool for CF. It'll work for both LED's. Just remember that you shouldn't "hot swap" them. Erv's board gets the voltage at boot and going from a V to a III will fry it. Reboot after switching then it's good to go.

Now if you meant 8AAA of non-rechargeable... don't do it! The CF limit is 11V. Frying a CF would be sad.

[LAN-ED-TUL]

The ultra sound board has a setting for the Lux V which drives it at 700ma
for now its in the vader saber, and running the red/orange L3. i remember the other led settings in the audio menu. i was just curious bout what X was sayin bout the overdriving them.

soon as X gets back to me with the details, im gonna go in with him to get a seoul green led, and get a heatsink plate from Tim and a quick connect, cuz my MHS hilt i setup with a quick connect to do swapping leds if i wanted to. its got that puck for the LV led inside it driving it now, and X stated i can directly swap it out with the seoul green, and prolly get a lil more, brighter that way, and if not much brighter, at least the runtime on the batts will be greater than it is now.

[Do-Clo]

I overdrive my leds sligthly and I don't have any problems with failure. The big problem with the Lux v is the amount of heat the darn things generate, so I normally don't use then. I stick with the K2 or the Lux III. The last K2 leds I got I had some problems with the led domes falling off and I had to epoxy the darn things back on.:roll:

[LAN-ED-TUL]

really, i knew of the big thing they were sayin bout a recall, or something, on a batch, cuz of similar incident happening. maybe you got some of those bad leds then bro.

[Count Malik]

I'm thinking of going to a lux. V for my next saber. As for K2s I had a hard time soldering them. Plus there not much brighter than a lux. III to me.

[LAN-ED-TUL]

my LV green in my MHS hilt is really darn bright, im anxious to see when i get the green seouls from X if those turn out a lil brighter or not. at any rate, as he said, my runtimes on batts will increase. if i understood it right, i have a 700 puck drivin that LV right now, and the new seoul wants 1000, so it wont be maxed, it will be undersriven a lil bit, so i shouldnt blow the led, but it may turn out being just AS bright as the LV is, but greater batt life in the end.

[Novastar]

As to what X is saying, and also the thing about over-driving... for what it is worth, I am here to confirm all that to newcomers as well!

YES, you can "overdrive" (within reason) an LED by giving it more than its listed max continuous current. Within REASON. That does not mean doubling the current, lol. Although I've seen that work too!

YES, that will generate more heat. Do-Clo said it on the Vs. A LOT more heat.

YES, in *general* it will get brighter... but some LEDs will differ on how much more you get--if you can even detect it visually.

YES, even if you cut in half the lifespan of a particular Luxeon LED by overdriving as above, you will almost NEVER see it die within your lifetime. It would still have about 2000 days of usage at 24 hrs./day, 7 days a week. Gee, is that enough???!!?!!

YES, for heaven's sake, X-wing is right about the current thing! JUST GIVE AN LED "what it wants" regarding current!

YES, if you're going "direct drive" (without a resistor) you need to be very careful, and match the battery voltage with the forward voltage of the LED. If you can't, you'd better use a resistor.

And yes, in a way--with Ultra's board... it *MIGHT* have been better if the voice described both the "luxeon style" AND the current being driven... but X-wing paints it out very clearly. In fact... you could technically make a saber staff with an Ultra:

* Two LEDs wanting 700 or 750ma max cont. current
* Select Luxeon K2 Blue/Green/Royal B/etc. (1500ma)
* If you wire it correctly, there you have it. :)

You could even do two LEDs wanting 1500ma max cont. current, but I wouldn't recommend it, as the wiring would 1/2 your runtime.

[xwingband]

YES, in *general* it will get brighter... but some LEDs will differ on how much more you get--if you can even detect it visually.

http://youtube.com/watch?v=Cgo48tNSUZg

Amen! I don't think I ever want to bother with a K2 at 1500mA. I haven't tested it with all my LEDs but Rebels it makes a visible difference from 700mA to 1000mA.

Mostly I made the topic to make people think. On a driver the volts of the LED and batteries isn't a problem as long as you have enough. To quote the Ronco commercials "SET IT AND FORGET!".

[DACOTA]

Yeah, voltage is like water pressure, you just need enough to push the electrical current.

Nice topic X-wing. And that was a good quote too.

[Eandori]

A correction needs to be stated. Xwingband said...
"Can I run _______?" Is irrelevant! If it's an LED and you match the current volts don't matter.


That's not really true.

One example would be using a Green Luxeon V. The forward voltage is around 6.85v at 700mA of current. If you use a luxeon LED like that, a Plecter/Ultra/Buckpuck to drive it, and only give it a 4-Cell AA battery (4.8v) then you WILL NOT GET 700mA to your LED.

The specific measured input voltage from the battery at all times must stay ABOVE the voltage the LED requires to keep that constant current to the LED. If you are using a red luxeon III and give it a 2.4v battery for power... it will not get even close to 1.5A.

Simply put, an LED does not care what your driver is. If you want to push 700mA through a green luxeon V, your voltage will have to be somewhere around 6.85v to the LED TERMINALS. Period. If your battery was only putting out 5v, then what you need is a charge-pumping circuit that can upconvert to the required voltage.

Crystal Focus boards, Buckpucks, and the Ultraboard do not perform voltage up-conversion. They simply maintain current if and only if the battery supply voltage is over what your LED demands.

[xwingband]

Eandori, I'm trying to hit a much lower level of thinking. I know that's true, but it's not my point of posting the topic... I was addressing the idea that people suddenly think the playing field has changed completely because the LED isn't a III or whatever.

I see constant questions of: "Can I run a ______ on _______?"

Well...

Can you:
A) give it the volts it wants? If yes:
B) can the driver give the current it wants? If yes:

YES!YES!YES! You can use it.

Example I see most often: Can I run a Seoul P4 on and Ultraboard? (or swap for any combo of Rebel, V, K2, Cree, and CF board)

Now let's look at it:
Can you give it above 3.8V or so... Yes. Can the Ultraboard give 1000mA... Yes (the III white/green/blues setting which is more correctly 1000mA).

I also saw people fretting thinking that if they used a V setting on another LED it'd fry it... I'll just lay it out, that's stupid if you think about it.

What happens when the batteries get lower than fresh on a driver? Does it dim? No, it will keep the current going as long as it has "enough". What enough is, is another ball of grease that you are talking about. I'm trying to combat the absurd idea that say you hooked up an Ultrasound with a III and put it on the V setting it'd fry because it's going to send 6.8V... NOOOOO! It will send whatever volts the LED wants at 700mA (V's current).

[xwingband]

I want to seperate this from the previous one...

An LED is a diode...it has a resistance. A resistance is volts per ampere.

Each LED is slightly different. Thus the binning...

SOOOO... I'm trying to convey the constant current idea. A constant voltage driver is absurd for an LED because if you take the above you'll realize that if it sent a fixed voltage the amps (current) would be everywhere.

So to make sure you are giving a constant current (brightness) the driver will change the voltage to give what the LED wants. That's why a III on a "V" setting works, or a III on the K2, etc...

[Obi-Dar Ke-Gnomie]

Thanks, that's helpful.

[Novastar]

Since this topic is about driving an LED with no resistors, or at least akin to that... let me confirm what X is saying:

Let's say we have:

If... Driver + LED...
Then Batteries can be nearly any voltage (within reason) that the board can support... and you then set the current to where the LED is best at for you. THIS is basically what X means by "voltage doesn't matter". Within REASON. You cannot light up a Lux III Green with 1v. That is just stupid. Just like you can't light up a Lux V with 3v. that is also very gay. BUT... you can give BOTH of those 7.2v with a driver, control the current, and BINGO. No problem.


If... *NO* driver + LED... (maybe even no resistor!)
Then Batteries should be AS CLOSE TO the LED's forward voltage as is possible, and preferably a *tad* bit below. This way, you will not need a resistor (or only need a very tiny one), and you won't be "burning away" any power. The resistor acts as a certain "choke point/gate" for the batteries, and will only allow so much juice to make it through to the LED. So where does that extra energy go? Essentially "nowhere". It gets used up as heat, and you never really "see" it via the light. It's a big waste. So... if you're going to do "direct driving"... or throw in a resistor... try your BEST to match things up perfectly if at all possible!

Best examples I can think up (and have used successfully without issue and LED problems):

* Lux III or K2 "Light Side" [Green, Cyan, White, Blue, Royal Blue]
* 3.6v or 3.7v Li-Ion Cell
* No resistor.

Why no resistor? Because the Lux III/K2's fwd v is around 3.8v or 3.9v. PERFECT for the 3.7v cell, which initially "slightly overdrives" when the charge is full at first, and the cell spits out 4.2v or so. In a short time, we get closer to 3.9v, which is the most ideal brightness... and later, we drop to 3.7v for the major duration of the cell's charge cycle. Once we drop to 3.4v or so, the saber is nearly useless, and it's time to replenish the cell's juice! :)

In my thinking--an absolutely PERFECT setup for a very simplistic saber where you do not have/wish to have a driver.

* Lux III "Dark Side" [Red, Red-O, Amber]
* 3v Alkaline, or even 3v Li-Primary (as X-Wing has used!!! Very smart!!)
* No resistor.

Again, why no resistor? Because the Lux III's fwd v is around 2.95v. PERFECT for the 3v Li-Primary cell, or two 1.5v Alky cells... which drive the LED almost exactly perfect. In this case, no real overdriving is occurring, and if you count 0.05v as over-driving, you have some serious brain issues that NO one or no thing (not even a brand new CF) could ever fix! :)

Besides, as X has mentioned (and many others)... LEDs are not a perfect science. LED X will be "best" at 0.15v higher than the same type of LED which is called LED Y. The binning of LEDs also figure into this, simply because of the nature of creating them, causing different shades of color (measured in nm) and so forth. You never TRULY know the LED's "best" voltage and current "sweet spot"... unless you test it 100% on some kind of spectrometer or dedicated power supply with a bunch of dials to help you truly nerd out over it.

BUT... the specifications that are made about LEDs are (for the mostpart) about as good as an estimation as anything. Trying to milk out an extra 5 lumens by dorking around with an LED *MIGHT* be of value... but I seriously doubt it is worth it due to the time invested and results realized. So your LED is now 5% brighter than a similar saber next to yours. So what. Can you really detect 5% with your eyes? Not a chance.

Anyhow. More blabbing from me... in hopes that people get the understanding on it. Even though it isn't the WHOLE story... you get what you need, just like X said.

[Eandori]

I wasn't saying anything about hooking up a lux III on a board with a setting for lux V. Yeah that will fry the LED.

What I said was if the battery input voltage drops below the required voltage of the LED, then you won't hit your desired current. That includes when batteries get low.

So sticking to the luxeon V example. You connect a 8.4 volt (rated) pack. It actually ends up measuring out to around 10.5v with no load, but when you yank 1 amp out of it the pack drops to around 9v under load while fully charged. Your LED uses around 7v forward so you have around 3v of drop at 1 amp for 3 watts dissipated in the board, and 7 watts dissipated in the LED.

Now over time that battery starts to die. Say it drops all the way down until while driving the LED as hard as it still can, the 8.4v rated battery is actually only pushing out 6v. Now.. your LED will not be getting the current it wants. Probably somewhere around 500mA instead of that 1A.

I had a 7.2v pack hooked up to my last saber with a CF board driving a green lux V. It would be fully bright at full charge. Then after like 15 min my saber would dim a few notches (down to what the green K2 puts out) but still stay "on" for another 90 min at least.

I understand what you are saying about making it simple. But you can't remove that part of it. It's just not true. Your battery (while under load) must remain above the required voltage of the LED or you will not get the current.

[Eandori]

So to make sure you are giving a constant current (brightness) the driver will change the voltage to give what the LED wants. That's why a III on a "V" setting works, or a III on the K2, etc...
ONLY on downconversion of voltage. Not upconversion. That requires a circuit called a charge pump and from what I know they are not built into a buckpuck, a CF board, or Ultra's board.

Don't try to simplify this for people. You will get their LED's fried.

If you take a Crystal Focus board, boot it up and power on with a luxeon V. Then hit the ignition switch again (powering down the blade, but the board is still alive) replace with a red luxeon III, and power on... the LED will fry.

Don't do it to prove me wrong, you will lose your LED.

Why?

Because when Erv' made the CF board, he did build it to regulate current YES. But.... the way he did it is on first power on it detects and sets the required voltage for THAT LED to hit the requested current value in the file. If you "hot swap" the LED's and re-ignite the blade, then your CF board will go straight back to the voltage it just detected before to hit that 1 amp value... 6.85v on a Lux III. Which fries it. The work around is you MUST reset Erv's board when you swap an LED.

A buckpuck will work for hot swap. But it works differently. Just like you have assumed, it drives entirely based on current and it detects each time. Not on the first boot like a CF board.

Now for the ultra board? I really don't know what it would do. It depends on how it's built. I will ASSUME that since it has a "setting" for luxeon V that it will go for an average current for an LED with that high forward voltage. But it could still go either way based on how Alex designed it.

So short story... don't simplify it too much for people. You cannot leave some parts out or some LED's will get fried. You can't leave out a low voltage input with a high end board will result in a dimmer LED. You'll then get all kinds of questions asking why that's going on.

[Eandori]

An LED is a diode...it has a resistance. A resistance is volts per ampere.

Carefull with that statement...

An LED is NOT the same thing as a resistor. A resistor has resistance just like a diode yes. But a resistor is totally linear response. Take a 1 Ohm, apply 1v across it and you get 1amp. Give it 5v and you get 5amps. Give it 7v and you get 7amps. Etc. Linear.

A Diode is not the same. They don't conduct current until their forward voltage is met. Then their "resistance" drops off very fast. Not linearly at all. I even drew up some graphs to illustrate this but I don't have a working online storage to upload them to ATM.

Novastar made a big post talking about using LED's without a resistor. While that can work, it's easy to destroy your LED. It's NOT a resistor, and it does NOT act the same way. If you really know what you are doing... go for it. If you don't, then make sure you learn basic electronics or be willing to risk your Luxeons.

[xwingband]

Eandori, I understand but you're complicating it and I think we can simplify it so people at least grasp it.

I wasn't saying anything about hooking up a lux III on a board with a setting for lux V. Yeah that will fry the LED.

NOOOO!!!! Thereis not a driver in the world that will have you set up a voltage. That's what I'm getting at. You'll set it at the amperage and the driver gives it what it wants.

Yes, hook a V up to a CF then go to a III and it'll fry. That's a by product of the CF not a driver. Change the situation to any other driver and that won't happen... like Yoda was telling people that they could run their V on other settings to be brighter.

Everyone was like, "Doesn't that send less voltage?" No... it sends what it wants at that current.

Like this:
ONLY on downconversion of voltage. Not upconversion. That requires a circuit called a charge pump and from what I know they are not built into a buckpuck, a CF board, or Ultra's board.

Don't try to simplify this for people. You will get their LED's fried.

No one needs to know this... a micropuck does up conversion. So I didn't explain every technicality... no one will fry an LED because I told them to to use a V setting. Why? Because NO LED driver sets the voltage before hand.

So sure I didn't explain avalanche fall of a diode. Most people can follow the volts per amps of an ohm to realize that you can't send a fixed voltage... because even though I didn't state it you have to accept that the voltage is uncertain or even dynamic if you see it depends on something else.

I'm firmly with Novastar to say *within reason*. I'm talking about the volts of the LED anyway. For now I'm ignoring batteries with the qualifier that you have "enough" and within reason (not above what your driver can handle).

So maybe my title is incorrect, but I wanted to get at the LED only to combat a lot of absurd posts that could done away with if what a driver does for the LED is understood. It's like the misnomer of Corbin's board as a "3W driver"... it leads people to think it'll only work for a III and the other misinformation that III=3W (Red III anyone? 6W K2's?etc...).

[Eandori]

I think mostly we are agreeing with each other, but I would definitely like to see us both using the same terminology.


NOOOO!!!! Thereis not a driver in the world that will have you set up a voltage. That's what I'm getting at. You'll set it at the amperage and the driver gives it what it wants.

Yes, hook a V up to a CF then go to a III and it'll fry. That's a by product of the CF not a driver. Change the situation to any other driver and that won't happen... like Yoda was telling people that they could run their V on other settings to be brighter.
Actually, that is exactly how CF drives an LED. From what Erv' directly told me, it senses current on the first boot, records the voltage at that current, then from that point on powers up to that voltage. I think it's done that way for reasons of timing. It takes time to power up his board to the requested current in the config file. So rather then "detecting" that with each blade power on, he simply does it just the first ignition after reset.

Is a buckpuck (sold on this website) different then a micropuck? I'll have to go look at the specs for those, but I was not aware they are built with a charge pump for voltage up-conversion. I know Erv's board does not have that. He directly told me.


I'm firmly with Novastar to say *within reason*. I'm talking about the volts of the LED anyway. For now I'm ignoring batteries with the qualifier that you have "enough" and within reason (not above what your driver can handle).
This is exactly the problem. You want to have your cake and eat it too. *within reason* would require that the user you are informing has some basis of understanding. They know what is reasonable. One cannot stay within reason, when they don't know what truely would be reasonable.

Somebody that does not understand how an LED works, how a resistor works, Ohm's law, and how batteries work like you, me and Novastar will probably NOT be very good at doing something "within reason."

If I was trying to adjust the timing of my cars engine, and barely understood how the engine worked, how could I ever do something "within reason?"

[Eandori]

Here is the PDF for a micropuck: http://www.leddynamics.com/LuxDrive/datasheets/2009A-MicroPuck.pdf

Here is the PDF for a buckpuck: http://www.leddynamics.com/LuxDrive/datasheets/3021-BuckPuck.pdf

You mentioned the micropuck does voltage up conversion. That seems true, but only to a point. It says on the datasheet that the maximum power is 1.5w

Absolute Maximum Ratings
Input Voltage. . . . . . . . . . . . . . . 3.0V 2 DC
Output Voltage. . . . . . . . . . . . . . 8.0V 2 DC
Output Power . . . . . . . . . . . . . . . 1.5W
With a max power output of 1.5w, and a driven current of 350mA, that gives a maximum upconverted voltage of 4.29v. I don't see that called out on the specification for minipucks, but it must be true if the reported maximums are correct. Driving a Luxeon V seems way out of range for a minipuck from what I see.

I just even did a quick test with my power supply and my green lux V. At about 5v, the LED was allowing about 300mA to flow. That's right about 1.5watts. So based on specs on the datasheet, I would expect either the minipuck to drive the lux V at 300mA at 5v, or if there is no limiter it will be overdriving itself (running beyond the listed max spec.) It's important to note something like that so sabersmiths don't buy components they can't use or overdrive their stuff without knowing it.

For the BuckPuck, this is what I see in the specification about upconversion. (page 3)

Fixed Current Drive

The fixed output versions of the 3021 are designed to supply their rated current to one or more LED junctions. For example, a 350 mA rated unit will drive up to six Luxeon* I LEDs connected in series. Due to the nature of the buck regulator, the input voltage must always be higher then the total forward voltage drop of the LED junction(s) connected in series (2.0V for DC models, ~4.0V for AC models).
Quick note, a luxeon V at 1 amp is probably around 7v forward on the LED. So your buckpuck driving it would require a minimum battery voltage of 9v while under load to hit that 1 amp on the Lux V.

So it's verified. Buckpuck does not upconvert, micropuck does... but to a small limit.

[xwingband]

Yup, I think we're on the same page, just differing on how much is "just enough knowledge to be dangerous". LOL

I'd simply like for a person to be able to look at a few numbers and be able to solve the "will this work?" question.

I don't think it's a horrible leap to look for the typical forward voltage of the LED, the max voltage your driver can handle, and what amperage the LED wants. From there you should be able to answer some basic questions.

[Eandori]

Now that we have a huge a convoluted thread about this.... :)

Perhaps we should email back and forth, come up with a condensed version of what is written here and repost/sticky it.

[Novastar]

Aww MAAAAAN!!

You guys went all Angry Video Game Nerd on the thread... lol!!

Sorry to say, Edwin, but... X HAS YOU ON THIS ONE!! If you over-complicate it for the basic users, the repetitive current questions will continue to pour in. If people are told to try to match the LED current and fwd v as best as they can... that is safe and "within reason".

I even pointed out that giving a Lux III Red-O like 7.2v is just plain ridiculous, and if you're not doing a driver, it's just LED homicide, hahahahh.

Maybe the Bard's advice here (Hamlet's advice to the troupe of players he encounters in Hamlet... which is really Bill Shake speaking out through his own text):

"Suit the word to the action, action to the word."

************MODIFIED FOR LED NERDS:************

"Suit the LED to the current, current to the LED."

or...

"To LED... or not to LED... that is the question!" hahahaha

;) 'Nuff said.

[Eandori]

I don't care if "X-wins", I'm not trying to "win" a debate and I never was trying to "win" a debate.

I wanted to help people without years of experience and training in electronics build better sabers. That's my goal. I have a steady job, a good family. I don't need to win debates on a message board to boost my ego. That's not what it's about.

The facts stand and everything I said in this thread is 100% correct. If you take Xwings earlier comments then you will have people frying LED's and wondering why their setup is getting dim on a board that was "supposed" to keep it bright.

Sorry Novastar, but that's why there's an entire degree focused to the study of electronics. Because sometimes you CAN'T simplify it without throwing out needed details.

[Novastar]

I was speaking mainly in jest, but... I'm not all about any egos here.

I am not saying nor did I ever that you weren't 100% correct. I think X-wing also agrees that the facts are the facts...

I just think perspective can be important, especially when many saber builders... simply do not have the degree, resources, tools, experience, and/or "troubleshooting/repair order of operations skills" that you might have from your extensive degrees and line of work.

Anyhow... I do understand what you mean... if someone asked me to just "simplify how to put together BOP I or II"... I don't know how short I could keep the descriptions... but I do believe it is possible for me to tell people in a BASIC way... "here's the general idea".

But yes... the "uber" folks such as you or X-Wing or whomever else will CERTAINLY be working with the details, as THAT is what separates the designers from the DIY "just for fun" folks.

[begin humor mode] I mean, egos? Come on. Maybe some people think that sabers make them cool. Whatever. They're not cool. You think I'm cool? I'm not cool. Look at me. I've got a flubbin' sink tube in my hand, I'm tryin' to be a wannabe jedi. That's not cool. You want cool? Oh look, I'm waving it around with a stick O' light shoved into it and postin' videos in the dark on youtube. I feel cool, just like an idiot with a fistful of dooku. [end humor mode]

*sigh* hehheheh. Alright, it's not that funny. I can't be funny ALL of the time. Well... unless I'm naked. That'd be funny. Well... sort of.

Just not in BOP III. :O

[erv]

Well, it's true that I have a specific point of view in this debate. True, since I've been teaching electronics and tend to be accurate, I personnally think that everything must be explained & detailed, but within a certain limit.
This is the "problem" : where to put the limit between no real information and the whole thing with mathematical equations...

My background, personality and the fact that I'm self taught for many things drive me to over expose and over detail things. There's however a difference between detailing and making things too complicated. There's also a difference between complicated and complex.
When someone says that something is too complicated, it can mean that he hasn't the right "educational level" (some times mis called "intelligence") OR... that it's badly explained or taught. So called bad students sometimes have bad teachers or unadapted teachers.

Now, my personnal problem goes with the people that "don't have time to learn more" because they "just want a lightsaber"... but they don't have the money to buy it ready made /commission someone to build it AND they want to try to build it anyway.
When you read a book about a certain topic (like "how to build you own vaccum formed machine"), you generally don't have shortcuts. If you buy this book just to watch picture but still think about doing it with a hair dryer, this is a stupid approach.
I'm then going to self moderate that by adding that some of us are teenagers, like 16 years old and, yeah, for sure, they're not attending university classes about quantum physics. I'm not putting everyone in the same basket.

Building luxeon sabers is hard. It's a complex mixture of electricity / electronics / wiring / soldering / anodizing / machining / threading / cutting / have-to-hands-that-work-properly-ing / common-sense-ing and some more.
It's fine if some of the list above is missing in your personnal skills. It depends how much you are ready to invest (time, money, research, work...) to fill the blanks and be able to get something nice.
Being accurate is one of this skill (personnal opinion). Using appropriate vocabulary is another.

On my side, I'd say that I used to overcomplicate things, but I'm trying to improve myself. However, I think that it's a waste of time to put an excel spread sheet on a webpage with 20 columns and 45 lines to give a pre calculated resistor value for every luxeon combination of model / current / batt pack solution. This is not teaching and this is not sharing knowledge, it's exactly the oposite.
It's give the impression to be sharing while you answer 2% of the question.

then, the user might use well this spreadsheet, but will wonder a month after which resistor to use with a little 3mm and not a luxeon. Or the person will simply use the same resistor without thinking that it will pass 1A into a little led that accepts 100 times less and the customer is REALLY surprised of the smoke and smell he gets...

Now look in my user's manuals. Probably they need to be rewritten with better english and better pedagogy aspects but... I give the general way of calculating things, and I add an example to it. Then it's rare that I get a question, or sometimes, it's just to confirm that the result is ok.

The other point is that forums and email are just unadapted tools for what we are exchanging here. Let's be honnest and what how the thread goes, it slips on oil (or mud... or worst - same color- ...) in 2 secs... simply because it takes SO MUCH time to take precautions in this informal media so that info isn't mis interpreted. That's why I'm also now self documenting my work in articles (equivalent of a sticky on a forum) once the summary and formatting of info is correct.

NO, there isn't GENERAL RECIPE that will always works with the plurality of devices we are using. Don't try to compare things that are different.

Now about a few points that have been discussed here, and so that you can be rewarded to read all my poetry :

- terminology / simplification : I agree with eandori. Specifically on the "luxeon is like a resistor". First thing is that it's incorrect and second it's not a "pedagogical simplification" that would help. Sometimes a metaphor or comparison, although not totally correct can be helpful for explaining something, but it's not the case here.
LED are a semiconductor. Semiconductor isn't related to a person driving half of an orchestra. It's an ACTIVE electronic part, as opposed to a PASSIVE one, like a resistor. An ACTIVE part needs power to work.
The LED is a diode, specific in a sense that it emits light (visible or not). LED = Light Emitting Diode. The reaction of LED are linked to a curve relating current to voltage. It's totally non linear, and is basically almost no current until a threshold, then an exponentially rising current as soon as you just increase a bit the voltage. That's why the slightest mistake on the voltage applied to the LED will "open the gate" and let a HUGE current thru it.
That's basically where the statement "the LED eats what it wants / need" comes from.

- LEDs must be current driven. A static or dynamic system must servo the current in the electric path. When voltage is constant (provided by an DC adapter plugged on the mains for instance), it can be as simple as a current limiting resistor. The resistor will absorb the difference between the wallmount adapter voltage and "the voltage at which the LED goes for a specific current" and will transform this excess of voltage into heat.

- current regulation : most of the drivers we are using (as the topic title says : no resistor here) are doing a step-down conversion (buck converters). If the voltage of the batteries stay above the threshold voltage of the LED (what is called the forward voltage), current is lowered and averaged by a chopper (no helicopter in that thing). To limit the current, power is applied for a certain time, then shut off, and so on, periodically. The smoothing is made by a coil, or self-inductance, generally this winded copper wire part (wire is winded around a ferite pot/core) that is just next to the luxeon output.
The time during which the power is applied changes over time, and increases while the batteries are going down.

- step up converters (or boost converters) : another system that fights the fact the batteries provide a voltage lower than the forward voltage of the luxeon. Thanks to the ohm low ( U = R x I), you can increase the provided voltage but it will suck more current. For achieving that goal, energy must be accumulated before being released, still using a coil, since it's a current accumulator.
As an example : think about the gear system of your bike or a middle age crossbow. The latter was impossible to arm by hand, you needed to spin a mechanism. With a lot of turns (current), the rope was getting more and more tight, energy is accumulated, then released (the arrow is released and moves, it's equivalent to a difference of potentials, or voltage)
Advantage : current is provided almost until the battery is TOTALLY empty.
Those converters / drivers are not so popular in saber technology because they use more current, autonomy will be reduced, but it's a nice way to light up a lux V with a low voltage battery setup.
On the other side, it's VERY popular in the flashlight world, where the idea is to suck all the juice of the battery instead of getting it dimmer and dimmer as soon as the threshold is reached.

- SEPIC converters : it's one possible topology for making a buck-boost. No easy to make / design, but some flashlight have that. It can start by doing a step down operation, then when the voltage isn't enough "turn into" a step up converter. For instance, my ultrafire C3 flashlight accepts 1.2 to 4.2 volts to drive a white luxeon (forward voltage generally around 3.7v). It therefore works with a AA rechargeable ni-mh, or alkaline, or 14500 li-ion (3.6v / 900 mAh, same form factor as a AA).

- why not HOT SWAPPING luxeon on crystal focus.
Crystal Focus is doing step down current regulation. To my knowledge, it's the only board that dynamically synchronizes the sound duration to the power up / power down ramp effect of the blade with the accuracy of one sound sample.
Current regulation with instant start are very simple cause they don't have to ramp the current and monitor it at the same time. The servoing is much more simple.
In my case, I have to remember, when the saber is off what the state of the batteries are. Just like diodes, batteries are not linear for current available versus measured voltage. When I power up crystal focus IT CAN'T KNOW how much juice the pack can provide, and therefore CANNOT calculate a ramp duration to match the sound duration. That's why the first ramp is generally not accurate in duration.
Once the battery juice has been measured once, I have a "target" for the current servoing for the connected luxeon. The second power up will be smooth and accurate in duration with the sound. Change the luxeon while the blade is off (but power still applied to the board), and you **** UP the whole thing. I naturally payed attention to that when playing around myself, but eandori is the one who tried... and fried (I owe him a beer for that).
that's why it's now written in B&W in CF user's manual.

I know, that was long but... you now know me as an academic b@stard :roll:

Erv'

[Darth Morbius]

That was a thing of beauty Erv!

Wow....Just WOW! :)

[Lord Maul]

That was a HUGE post Erv, but VERY useful.

Time to go let my brain cool down :mrgreen:

[DarthFender]

"Can I run _______?" Is irrelevant! If it's an LED and you match the current volts don't matter.

Example: Ultraboard has four settings: V , III Blue/White/Green , K2 , III Red and Amber

THIS REALLY MEANS: 700mA, 1000mA, 1500mA, 1540mA

So if your LED wants 1000mA you can select the III Blue/White/Green setting. Even if it needs 7V it'll drive it. If your LED has a target of 700mA you can overdrive it at 1000mAh. So a V would be overdriven on the III Blue/White/Green setting.


I just want to be clear here, Xwing, you still need a battery pack that will cover the forward voltage of the LED even if it produces enough current. For example I cannot drive a LUX V from any board of I'm isong 4.8v Battery pack? Right? Or are you saying that the driver (constant current) wil cover it even if the pack does not cover the voltage drop?

EDIT: Forget all that, I just read Erv's Post.

[Eandori]

Exactly the point I was trying to make. No it would not drive the lux V correctly with a 4.8v battery.

Just to be clear here, this is what the reality would be and why I said "it cannot be simplified like that..."

4.8v Battery + Luxeon V + Plecter board = dimly lit LED.
4.8v Battery + Luxeon V + Ultra Board = dimly lit LED. (I think... ultra does not upconvert. Right?)
4.8v Battery + Luxeon V + Buckpuck = dimly lit LED.
4.8v Battery + Luxeon V + Micropuck = dimly lit LED, possibly overdriven driver.
4.8v Battery + Luxeon V + resistor = dimly lit LED. Even if no resistor, will not be close to full current.

So what if you have a 7.2v battery? A 8.4v battery? A 9.6v battery? When your battery gets low power, it acts like a smaller weaker battery. Providing less voltage and current. So even with a "proper" battery your LED will dim in the right conditions.

I completely applaud the effort to make this stuff easier for other people. I'll even do my part to help. But don't leave out important facts that really alter the workings of the unit if you are teaching how it works. We just need to find a better way to explain the basics.

[BlackDOG]

Thanks Erv' that was very helpful ..........

Nova---you kill me...I am still chuckling about about the angry video game nerd/ sink tube waving nerd in the dartk thing.......

Edwin----Thanks for being particular...it helps diligent noobs (like myself) figure out what you are trying to say......the problem is there are not so many dilligent noobs as there are make it light up now/ color by numbers/ needed it for goofycon 08 yesterday folks..... and that was the audience Xwing was trying to get to.....

Professionally speaking, my clients are of this last variety...they end up in jail or on the wrong side of a summons because they did not chart out their course prior to setting forth....I really understand and appreciate how Xwing is trying to satiate the teeming public......

Case in point.......when I first showed up on this lil' ol patch O' cyber space, I wanted a saber YESTERDAY, I wanted a blueprint that I could follow and I wanted it brighter than anyone elses and I wanted it perfect and I wanted to be able to explain it all......

I WAS A PUTZ..........you can't gain reward without effort. I see that now.

SO, why do I post this? We all are trying get to the same place, we are just talking to different segments of the saber population....and this sort of post is helpful to achieve that.

[DARTH KALEL]

Well, I would just like to say, THANK YOU XWING!!!!!!!!! You guys have to remember the first time you saw a custom saber. The joy, the anticipation? and I mean a custom saber! And all that really means is a pieced hilt and a lighted blade, yeah it's cool to have uber sound and all, but, without that signature glowing blade it's just not a lightsaber. There are far more people out there that don't know nothing about electronics ie wiring and voltage, wattage. So I think it's a great idea to make it simple, for those that are young and like my brother in law, who has a learning disabillity, and don't understand anything about what you write, and needs to see things first hand. It's really arrogant to assume that if somebody CAN'T read up on the information that they shouldn't enjoy the same JOY we all get from ours. What's wrong with a LED wattage voltage/ wiring reconmendations, do you realize the easier it is to do and less complicated it is the more money TIM and others will make. why short change yourselves. If I were you guys I would have a ton of detailed instructions of how to wire anything saber related, IE secondary LEDs, PLIs, sound boards, drivers, resistors, and have each LED that we use, posted with recommended voltage and driver, resistor you name it. I mean I really don't think that if you make it easy that the value will go down on ebay, it's still hard work and alot of research, and the custom builders are great, but unlike the machine work that takes tons of equiptment to do well, the basic elec stuff we can all get at local elec shop and with a little practice and cheap basic tools can wire a light saber. Tim, I love that you offer the basic wire kit for the LEDs you sell, you are a very bright man lol and hopefully will keep doing this as other LEDs are available. Xwing keep up the great work, Erv, Eandori thank you for the always expert advice and NOVASTAR for your humor and truth, i'm no genius, I love to smoke, lol, and always have questions, if there was somewhere I could go to check what batt pack would be best or good for the LED I chose and what would be my brightest way to run the LED, cause lets face it that's all anybody really wants, and wiring the thing to work right in a hilt, then I wouldn't have to post useless threads and create more junk for nooobs to read, it's a never ending cycle, if you don't address this soon, as you should all notice the saber market has tripled this year, then these types of forums are just going to be overwhelmed with these questions. oh and i'm sorry i'm not reading through 82,000 posts trying to find what i'm looking for when I DON"T KNOW WHAT I NEED IN THE FIRST PLACE. IF it comes to machine work or doing something with my hands I have no problems, and I can wire and solder anything if I know how it goes, so please show the light masters!!!!!!


FACE IT WE ALL WANT LIGHTED SABERS, and we all want it now not 4 years later when we get our degrees and we all don't have the money to ship it all over the place to have somebody wire it for us when all they had to do was post a little pic, or answer a little question.

And remember too that when you make it easy to do the basics that means more sabers that can be upgraded with sound and other stuff as all the nooobs advance in thier learning.

[Novastar]

Thanks for the kind and thoughtful words Kalel... :)

The only thing I'll say is... LED sabers are improving all the time... but--it does indeed take thought, planning, study, and--alas--work.

Pretty much like all things.

[DARTH KALEL]

amen brother, I have spent so much time and effort, reading trying things, but with hard work comes great reward. I don't want anybody to think there is a 1 2 3 answer to most wiring questions but it would be nice to see how to wire a resisted saber no sound and a bucked saber with no sound , for those who either have lighted stunt sabers or just want something lighted till they have the skill to do better or the money what ever the situation. Well Novastar you always help me out even if you don't know the answer directly you are quick to point to who and where I might find the answer, that's what a master does folks. I am getting ready tomorrow to put together my superman saber, it will have a p4 4xAA batt pack and resistor, untill I can get a CF, then I will jump to a bigger batt pack because of extra LEDs I want to run and get rid of the resistor. I just can't wait till I get the CF to do it lol. I am getting so anxious to see the yellow blade mixed with the colors of the hilt yay lol

[Ambo]

DROOL....
http://lukehoney.typepad.com/the_greasy_spoon/images/2008/07/19/fried_eggs.jpg

God i have missed frying my brain on threads like this...i missed you guys....

[Novastar]

Ambo... now WHY did you resurrect this sad, pathetic thread? :P

Welcome back Ambo... and... hmm--you may need to remove your link below to ambosabers... :(

[Silverwing]

It's like the misnomer of Corbin's board as a "3W driver"... it leads people to think it'll only work for a III and the other misinformation that III=3W (Red III anyone? 6W K2's?etc...).

After reading over this conversation (being a padawan of sorts when it comes to sabersmithing) I have learned that you cannot correctly power an LED through a driver without AT LEAST matching the LED's required forward voltage. But what about the other way around?

But just to clarify X-Wing's statement for my fellow newbies and padawans, I CAN power say, a Lux V with the "Luxeon 3w driver V2" currently sold at TCSS. True, it runs 1000mA constant, but assume that I WANT to overdrive the LED, since it needs only 700mA.

The LED will only take what it requires as far as voltage is concerned, and therefore if you use a driver you can use a battery pack HIGHER than the LED's forward voltage without incident, provided the voltage is underneath the driver board's maximum voltage.

Any problems with that statement?

Obviously this topic has come and gone, but since I'm trying to learn and this thread is stickied, I figure it's easy to de-mystify the question here and save myself and others time and questions. ;)

[Novastar]

Silverwing... the entire point of (most) LED drivers is the following:

* They (generally) accept a range of voltages (let's say ~3.7v to ~7.2v)
* They will either spit out a "fixed" current... or have options (again--as a range) in order to regulate. So maybe 700mA, 1A, 1.2A, 1.3A, 1.5A
* They are attempting not to require tons of the voltage/current THEMSELVES in order to run. In other words--the driver board itself shouldn't be sucking down 2.5v & 500mA of current... :)
* They often adopt a style of driving called "Pulse Width Modulation" (PWM). Look it up to get a general idea of how it works... in favor of extending runtimes, and keeping the LED somewhat cooler during such runtimes...

Comparing a "resistor to LED" and/or "direct drive" setup... ... to a driver setup... is just not really apples to apples comparison-wise.

It's true:

* With a direct drive / resistor setup... MATCHING THE BATTERY VOLTAGE to the LED FWD VOLTAGE is fairly smart + efficient

but...

* With a driver... you need to consider the following:

~ How much does the driver take to run? Likely around 0.5v to 1v... and a little current.

~ How does the driver actually WORK? Does it burn off "excess" voltage as heat? Or is it "smarter"? (for example, Force FX boards aren't really "smart" LED drivers... whereas CF handles current fairly intelligently)

~ How much voltage can the board handle? If you have a Luxeon V (~7v fwd) and you plan to use a board that can't handle such voltage... errm... what's the point? You're just going to kill the board.

So... a lot of stuff enters the equation.

Now ULTIMATELY... if you feed an LED "somewhere around the right voltage and/or current"... meaning give or take 0.75v and give or take around 500mA... really...

...you won't see THAT much of a visual difference. Whether you use a board... whether you direct drive... whatever. Current is current is current, and voltage is voltage is voltage.

You just don't want to feed 9v into an LED that is "looking for" ~3v. That would be pretty stupid. Relationally, same for current. Don't feed 1500mA where only 700mA is the max rating. DUH.

Finally though... high powered LEDs (HIGH powered LEDs)... are fairly hardy. You can "abuse" them a little bit with the right heat-sinking and care not to leave them on for 4 hours straight.

But... caveat emptor... and mise en garde! :) You push one too far... and it's gone. Oh well. Get another one.

[Silverwing]

Thanks, Novastar!
That was a great piece of... theory? if you will...

So once again, the key phrase here is "within reason."

Obviously, if an LED wants 700mA at 6.8v, you dont want to shove 2.2A at 12v through it; that's just asking for trouble. I was just unsure if I should be getting my current and voltage to an exact science here (I.E., using resistors or regulators before the board). I just dont want to be wasting perfectly good electronics, especially since high grade sound cards seem to be so elusive these days.

[KuroChou]

I think the point was confirming the thought process

if sound(regulator)maxV > battV > LEDfwd
then LED lights (without burning) for batt mAh/LEDmA hours.

I think that pretty much sums it up....

if you're using a regulator that makes it's current adjustments based on a static reading of the batteries' voltage, then the LED will always get dimmer when the supply voltage drops... unless:

you overshoot your minimum voltage (board Vdrop+LEDfwd) significantly, and use a separate voltage regulator BEFORE the current regulator.
This is more prudent and practical in direct drive, or relay drive circuits.
e.x. a white P4 wants 3.25V @ 1A; using a zener diode/transistor+resistor regulator, you can set an output voltage at 3.25, and then have a current regulator to keep the output at 1A, meaning that as long as your supply voltage is greater than 3.25@1A= 3.25W you will always have a fully lit saber.
This means that if you have a supply of say 4AA NiMH, you have a total power supply of (1.2v*2600mAh)*4=12.48W/h; 12.48Wh/3.25W=3.84 hours theoretical runtime.
Of course this is assuming that the batteries can make a complete drain cycle, which as has already been stated, can't be done without scaling the voltage.
Instead let's assume that the batteries lose their charge at a rate of 20% (or .96V) per hour, that means that our run time is actually reduced to an effective 1.61 hours maintaining maximum brightness, and completely failing to run afterward.
Considering that's without special packs or cells, it's not too shabby.

Of course 20% is a random hypothetical number, and we're also neglecting any voltage drop, resistance, inductance, or heat from the regulating circuits, sound board, and hilt in the equations.
Round it down a little and we're still hitting in the 1.5 hour range people on the forums have been reporting.

....I'm no expert, but I think that pretty much covers it for a best case hypothetical scenario.....

[Novastar]

Kuro, I think you're over-complicating things in some parts of your last post... and over-simplifying some others. One in particular regarding battery discharge...

Differing cells output the whole "less voltage over time/drain" in differing ways. A real-world example is the Li-Ion cell... which tends to have a "flat" discharge curve: the Li-Ion maintains a fairly solid voltage up until something like the last 10% of its charge... and then drops significantly (and a PCB protection circuit should be there to "save it"). Ni-Mh cells do not perform as such. Ni-Cd... different too. Alkalines... behave differently as well. Also, all of these cell types behave dynamically/differently under "heavy" drain (let's say =>2.5A)... or even "spikes" of drain (suddenly drawing ~4A, then back to ~1A).

Additionally, you have the fact that the human EYES can't truly tell the difference between LED type "X" driven @1A... vs. that very same LED "X" driven @1.1A... or possibly even @1.5A. Same goes for the voltage, as it is relational to current. Running @ 3.3v will often yield "the same" visuals (for HUMAN EYES, not light meters) as would running @3.5v or 3.6v. Possibly more, too.

Finally, although the theoretical runtime of a cell (let's say "2600mAh" rating) is a good ballpark figure... you AGAIN (as my previous post mentions) have:

* How does driver work... PWM? Fast "blinking" of LED? Basically direct-drive?
* How much juice does driver take/want?... 50mA? 87. 66mA?? How many volts, too...?
* If you have a speaker... how much is it draining?
* Ok, although the LED "specs" say "3.85v fwd" or whatever... when it ACTUALLY is being driven... is it sucking away MORE? Less? etc.

So, by the time you attempt to figure in all of these things... it's just a bloody mess, and it's a crude "guestimate".

To me--direct drive is pretty much the closest way you're going to see a GENERALLY "more predictable" runtime when you're considering that it's simply LED + possible resistor + cells. Then... sure... it's easier to a point.

But for example--on my CF sabers... between the LED driving (PWM, and btw it's a 4-die RGGB w/ FoC setup) and the speaker, and the board, and the indicator LEDs and the motor...

...well my the little "2600mAh" rating on my Li-Ion packs... really don't count for squat!! I consistently draw "PWM'ed" ~1.21A... plus the motor, plus the little LEDs, PLUS the speaker... and SOMETIMES we have the flash-on-clash (FoC)!!!

So... once it gets THAT complicated... good LUCK on trying to make a guestimate on runtimes!!! It lasts as long as it does. Something like 2 hours I guess. Who cares, I just recharge it, and actually I've never "run out" on any given day of usage... I throw it back on the charger. :)

[KuroChou]

Yeah... as I said, none of those figures were taken into account in the simple calculations, and by no means did I intend to, because then we're dealing with umpteen variables, entirely based on the builders preference.
I'm not the kind of expert to be giving that kind of advice anyway.
The limit of my electronic knowledge comes from a year of Electronics 1, my freshman year in high school, and whatever tinkering I've done since then.

Like everything else in this thread, I hoped my figures would be more of a guide than a rigid plug-and-play, and could be taken with a grain of salt and some personal directive on the part of the reader.
Anyone who has taken the time to read all the way through it, is likely more than just a casual builder, and is actually looking for some more advanced help.
As long as someone had the effort to look up the datasheet for their components, they could get the constants they need to solve their power and driver requirements pretty easily.
I agree that I severely oversimplified the matter of drain rate, but that's why you're here to correct the inadequacies of my posts.

I still feel like it's useful information so that, between the two of us, people with less electronics experience understand that even in a relatively static circuit, the saber electronics are practically a living breathing thing, and subject to constant change. Even things as obscure as the operating temperature of the saber can make a huge difference when calculating drain rates and voltage off of unregulated chemical batteries.
That being said, If they follow what I did, substituting with their own batteries, LED, and voltage curve, then they at least have a minimum ballpark, that they can add more complicated components to.
Most electronics calculations are fairly simple algebraic conversions, but they're a little harder to formulate off the top of your head.
I know in my personal experience, it's easier if I've at least seen what it looks like and how it works.
Once you start messing with thermal runaway, variable resistance, and drain curves, the it gets a lot more complicated, throwing exponentials into the equations, and making it less worth your time.
That said, it's again, more for a ballpark reference of what you'll need if given your specific components and desired runtime.

I kinda feel like the site needs a collaborative guide to advanced electronic mathematics. A kind of textbook or reference sheet of all the necessary terms and equations.....of course maybe I'm getting carried away again, as most people visiting for the first time don't even have the whole concept of Ohms Law.

EDIT: At this point I'm posting in the wrong thread anyway... I get a little sidetracked when it's too far past my bedtime.

[SithDuelist45]

I hate to take sides but i have to admit i agree with X and Novastar about the over complicating things. its like telling an 8 year old before he walks to school: "dont deviate from your default path to school". when instead you should say: make sure you go strait to school, dont stop for anyone or anything." not that im saying were all 8 year olds but you get the idea. lol and again im not trying to take sides, but as far as the Volts and mA's go im just starting out im am ordering my first electronics kit rightnow, so for a complete noob like me, i am getting quite confused lol...