What I'd do if I really wanted to use this module for the purpose described in the title is bypass the transistor altogether, and connect a lead from the cathode of the LED, then use the circuit described on the last page. Simpler than the alternatives. 
OldSteve:
Regarding the original pic, maybe if you'd mentioned the attachment in the text of that reply, it might have been noticed. Even better, when you attach an image, is to place the link to it inline with the "Insert image" button, so it's visible in the post.From your new pic, R1 isn't 1K as shown in your diagram, it's 10K. (103)
The transistor doesn't have a gain of 400 in this circuit, either. Where did you get that figure from?
If 5V is applied to the 100 ohm resistor, (I'm assuming you got the value of that one right), about 40mA will flow into the transistor base. So if the LED forward current is 800mA, the effective gain is 20.Anyway, the circuits previously described won't work with your LED module, (not by switching the "S" pin, anyway). A plain 3W LED would be better.
Here's the latest pic:-
Oh, in that case, the resistors are 10k and 1k (103 and 102)
So we start again. Or, at least, someone else can.
But do keep in mind that the transistor cannot handle 800mA. About half that is a nice, safe level.
All in all, if you want to do this, the best way is what I suggested - bypass the transistor and get yourself a MOSFET, then use the circuit you were shown. A more complex circuit is needed if you insist on using the "S" pin.
Looks like I'll just be desoldering the cob off of the breakout and using the mosfet from earlier with a more appropriate line voltage. I really appreciate the help folks!
rollerce:
Looks like I'll just be desoldering the cob off of the breakout and using the mosfet from earlier with a more appropriate line voltage. I really appreciate the help folks!
You could leave it in one piece and throw it in the parts box, then buy a stand-alone 3W LED, if this is to be part of a 'real' project.
I thought you were just experimenting, that's why I suggested simply bypassing the transistor on the existing module.
Edit: And make sure that you get a "logic-level" MOSFET, particularly if you plan to use a 5V supply. (But even if you use a higher voltage.)
And the higher the supply voltage, the lower the capacitance can be. Ideal would be 12V for the MOSFET, with 5V or 6V for the LED. (Assuming a LED forward voltage of about 3.7V)
I'd probably use a 12V main supply, so I'd then add a 5V DC-DC converter for the 5V stuff, with the MOSFET/cap etc connected to the 12V line.
I'd been planning on running the project off of an 18650 so it's beginning to look like I need to abandon the idea of a flash-and-fade and just go with a triple nickel or transistor based one shot multvibrator... It was part of some light effects I'm making for a prop laser gun out of an old nerf gun, necessitating the need for compact circuitry.
rollerce:
I'd been planning on running the project off of an 18650 so it's beginning to look like I need to abandon the idea of a flash-and-fade and just go with a triple nickel or transistor based one shot multvibrator... It was part of some light effects I'm making for a prop laser gun out of an old nerf gun, necessitating the need for compact circuitry.
Yeah right. You wouldn't get far with the MOSFET design on a 3.7V supply. It would work with a "logic-level" MOSFET, but you'd need a fair-sized capacitor.
The bigger problem that I can foresee is that since your supply is 3.7V and so is the LED forward voltage, there's no overhead for a series resistor. A boost converter would overcome your problems, but at a cost of more space. You're between a rock and a hard place. 
I popped an 18650 across the leads of the LED last night and it about blinded me. Was not expecting it to be that bright, lit the whole room for a moment. I actually came up with a way to get my residual afterglow using glow powder so all is not lost.
Again, thanks for the help folks. I'll use what I've learned here for a bigger project that's on the back burner.
rollerce:
I popped an 18650 across the leads of the LED last night and it about blinded me.
What value series resistor did you use?
Yeah, no kidding. That was my first thoght. The OP sounds like he might be too impatient ( to research before experimenting) . That last comment doesn't jive with the module schematic because the led "leads" are the anode and cathode, not the pins on the module board.
Another red flag is that "18650" is just a package size and doesn't indicate mAh rating so there is no way to know what that is without the vendor link or a photo of the battery label.
The comment rings of recklessness ( yet to be determined). Let's hope he didn't really mean what he actuaully said. ( if he used a series resistor then the battery wouldn't be across the led "leads" , would it ?)
rollerce:
I popped an 18650 across the leads of the LED last night and it about blinded me. Was not expecting it to be that bright, lit the whole room for a moment. I actually came up with a way to get my residual afterglow using glow powder so all is not lost.Again, thanks for the help folks. I'll use what I've learned here for a bigger project that's on the back burner.
If what you learned here resulted in connecting an led straight to an 18650, then you have learned nothing.
raschemmel:
Yeah, no kidding. That was my first thoght. The OP sounds like he might be too impatient ( to research before experimenting) . That last comment doesn't jive with the module schematic because the led "leads" are the anode and cathode, not the pins on the module board.
Another red flag is that "18650" is just a package size and doesn't indicate mAh rating so there is no way to know what that is without the vendor link or a photo of the battery label.
The comment rings of recklessness ( yet to be determined). Let's hope he didn't really mean what he actuaully said. ( if he used a series resistor then the battery wouldn't be across the led "leads" , would it ?)
Yeah. Another point is that an 18650 is a 3.7V battery, and the LED forward voltage would be about 3.7V, so with a series resistor it shouldn't be overly bright. Might not even light up. (Depending on the resistor value.)
I'm sure we'll be enlightened.
OldSteve:
Yeah. Another point is that an 18650 is a 3.7V battery, and the LED forward voltage would be about 3.7V, so with a series resistor it shouldn't be overly bright. Might not even light up. (Depending on the resistor value.)
I'm sure we'll be enlightened.
18650 would start at 4.2V or so at full charge
and depending on the cell, is capable of providing 2-10Amps during normal usage. So during a short, at least as much.
OldSteve:
What value series resistor did you use?
I didn't worry about a series resistor for two reasons, the first is that the battery voltage (tested with a multimeter at no load - 3.36V) is substantially less than the LED voltage (~3.8v), so no series resistor is indicated. The second reason was because I was only powering the LED for a moment, not leaving it on for a sustained period of time.
Also, this was done after I'd de-soldered the module from the breakout board, because I wanted to test the led without the extra crap on the breakout.
Oh dear oh dear oh dear.
You will not get far with thinking like that.
I assume you think that physics takes a break because you are only testing. I also assume that you do not know about LEDs and the forward voltage drop figure in a data sheet is typical and also depends on the individual LED, its age and its temperature.
You must always have some sort of current limiting when using an LED.
rollerce:
I didn't worry about a series resistor for two reasons, the first is that the battery voltage (tested with a multimeter at no load - 3.36V) is substantially less than the LED voltage (~3.8v), so no series resistor is indicated. The second reason was because I was only powering the LED for a moment, not leaving it on for a sustained period of time.Also, this was done after I'd de-soldered the module from the breakout board, because I wanted to test the led without the extra crap on the breakout.
As Mike (more or less) says. Tch tch tch.
Quite obviously the battery voltage was higher than the minimum Vf of the LED, or it wouldn't have lit.
To reiterate what he said: "You must always have some sort of current limiting when using an LED."
(I had to repeat it, that way it will stick in your mind better. 
)
18650 would start at 4.2V or so at full charge
and depending on the cell, is capable of providing 2-10Amps during normal usage. So during a short, at least as much.
It's much worse than you think...
Another point is that 1S Lioo batteries in the 18650 form factor can be found with some very high mAh ratings which means that, in a Lilo, the discharge current,, depending on the "C" rating , could be 45 or more times the "1C" mAh rating so a 3000 mAh rated 18650 1S battery ciuld source over 100A for a very brief period [. (3/135) * 60= 1.3 minutes.] 6.7 times the 1C rating:
Now DOUBLE that
6000 mAh 18650 1S Lipo
40000 mA
And it just gets worse...
High discharge 18650 batteries
208 Amps
If I'd blown the led by doing what I did, lesson learned. It didn't blow because the battery was close enough to the nominal voltage of a 3w white LED. Let's also remember that a 3w LED can dissipate FAR more amperage than your standard super-bright, and this particular package has heat dissipation built into it (the aluminum core PCB it's mounted on).
So what did I learn from my test?
The LED will be painfully bright at it's nominal voltage and will definitely provide me the powerful momentary flash that I'm looking for, and I will probably want to current limit it a bit just for the sake of reducing it's brightness somewhat.
I will have to plan to make my multivibrator capable of handling the high current that the LED draws (3w/3.8v=~800mA), although I can probably get away with underrating the components slightly as it will only be used for short bursts.
I also learned that it's a lot harder to do a flash and fade than I'd thought.
rollerce:
The LED will be painfully bright at it's nominal voltage and will definitely provide me the powerful momentary flash that I'm looking for, and I willprobablywant to current limit it a bit just for the sake of reducing it's brightness somewhat.
Not probably - definitely. Consider a fully-charged battery, straight off the charger.
Otherwise, buy a good supply of those LEDs, because you'll be replacing them regularly.
Let's say the battery is at 4.2V. And the LED Vf is 3.8V. And the wire resistance is 10 milliohms. The current through the LED would be (4.2V-3.8V)/0.01 = 40A. (Or a bit less due to the battery's internal resistance.)
Those figures might be out a bit, (or a lot) but you get the idea.
It's a bit late now, but this appears to be the OP's device together with a specification. Apologies if I am repeating something already buried in the thread.
There is even some Arduino code to drive it