Dorcy 8-LED to IR LED's?

Dorcy 8-LED to IR LED\'s?

Hi all! Google led me to this wealth of information! Never knew there were so many ways to mod a flashlight!
Here's what I'm trying to do, bear in mind I know almost nothing about electronics, but am handy with a sodering iron.
I have the Dorcy 8 LED in front of me completely disassembled. I picked up a couple of these to try this on.
I have a bag of IR LED's I wanted to buildinto a small lightsource for nightvision. Don't know the specs of the Dorcy, nut this is what I have on the IR's:
920 Nanometer
1.5 Volts nominal
27Mw/sr Power output @ max
20 Milliamps nominal, 30 Milliamps max
So I'm wondering if one of you experts can tell me;
Is it just as simple as soldering these in? Will they even work in the Dorcy? Finally, is there maybe a resistor or somethingI can change to make this even brighter (IR wise)?
TIA!!

Re: Dorcy 8-LED to IR LED\'s?

Those require less voltage than the whits which typcally require 3.6 or so. So as you can see big difference. Those IR leds only take ~ 20-30ma like the white's. I've seen IR's leds that take 100ma! But anyways, They will be overdriven, how much I don't know. If you didn't use the dorcy circuit, and just Direct Drived them from 2 cells they would probably be overdriven as well, espically with only 8.

You could maybe hook them up in a series/parlallel configuration, and put more Leds in and get rid of the reflector thing which doesn't help much anyways.

Best bet power wise would be to yank the boost circuit and hook them up directly to the batteries, only use a small amount of resitnace for each led to get them at the right rated power. Add bunch of leds as possible, you could probaly get at least another 8, probably a lot more in there. Or you could do some in series some in parallel and DD without resistors, like 2 sets of 8 in parllalel, then hook those sets up in series which would then require 3v to drive them all at specs, which is what 2C cells provide anyways...

Anyone else care to chime in??

Re: Dorcy 8-LED to IR LED\'s?

A dorcy single aa 3 led with boost circuit removed might be the winning ticket.
DD the ir leds with 1 aa. /ubbthreads/images/graemlins/icon3.gif

Re: Dorcy 8-LED to IR LED\'s?

Hmmm...I think see what you all mean. I DO want to overdrive them as much as I can to get this rig as bright as possible. The IR needs to carry a ways. Could go with like a 72 or 34 LED illuminator, but was looking for something small but bright and compact. Saw these in Target and thought a couple of these would be sweet! Wanted to use an Inova X-5 but couldnt figure out how the damm thing came apart (anyone ever get that head apart?).
Looking at back of LED board on Dorcy I believe they're already in parallel (xcuse blurry pics...only had Nokia handy).
Was hoping this would be as simple as changing out LED's and maybe changing a resistor or two, but I don't have the engineering skills or math to figure it out.
I think direct driving it would be way to dim...no? I suppose I could drill out more LED holes but wouldnt know where to put em or how to add the traces to existing.
Think these would blow if I just swapped LED's and used driver circuit? If I could get a better pic or list parts on board, would any of you have any suggestions to make it work? I have a DMM at work if I had to measure anything (with guidance).
I'm handy but I dont know how much I could work a serious mod on this. Thanks for the input!! I appreciate it. /ubbthreads/images/graemlins/smile.gif

Re: Dorcy 8-LED to IR LED\'s?

Here's what to do. Your led's are 1.5 nominal on average to pull 20-30ma. Take out the boost circuit and save it for another light mod. You'll DD off of 2C cells. Remove the stock leds. Remove the traces. Then fit as many IR leds as you can on there. Drill the holes for the leads. You can then wire them up with wires, you have plenty of room in the backside of the light it seems, since you removed the circuit.

Take the # of IR leds you can fit on there, and wire up half of them in parallel. Do the same to the other half, and then wire these to halfs in series. That way it takes 3.0v nominal to power both sets, which is what your 2C will make. Wire that to where the circuit got power, and you're done. You have a good chance that the Led's will be overdriven somewhat, as fresh cells will be more than 3.0volts even, and some IR will more than likely have a lower Vf, some higher possibly, you could always measure each one to find out what the vF is ...

Re: Dorcy 8-LED to IR LED\'s?

It sure looks like they are in parallel. I believe as someone stated they run at 3.6 volts and 20-30 ma I think the IR's run around 2.1 or so. You might be better off to run them slightly under driven. You could run 4 sets of two where the two are in series and the 4 sets are in parallel. This is the safest way and if you don't like it -- way under driven, you could try a parallel configuration for all 8, but they are going to be, depending on whether the board is current regulated or voltage regulated, quite overdriven.

Re: Dorcy 8-LED to IR LED\'s?

Ahh.. I c! I didnt even think about removing the existing traces and just doing with wire! Yeah I can do that!
Alright! I'll give it a shot and see what happpens! If I get this to work halfway decent I'll post some pics and some very cool total darkness shots. Thanks!
I'm still open to suggestions if anyone has anything creative! Glad I bought two of these. Maybe Ill get a couple more. I also have the 3 LED AA which is handy as hell. Doubt Id get any usable IR out of it though.

Re: Dorcy 8-LED to IR LED\'s?

kenny: He won't need the circuit at all. The circuit is there to step up the voltage from 3.0v from the 2C's, to 3.6 or so that the white leds need. The board is more than likely simply voltage regulated, and simple boost, not constant-current regulated. Your series/parallel config is like what I said, only the other way around, both works the same. But you won't need the circuit, as Vin will exceed the needed Vout or be the same. The circuit will boost it and way overdrive the IR LED's I'm afraid. I don't think it would DD and then boost when the batts get low, but then again it might? He stated the specs of his IR leds were 1.5 Vf.

TripWire: You could modify the other 2C with UV leds. The voltage in requirements of UV are the same as white/blue/green. So you can just directly swap the LEDs. Or add more, but I think it would deliver less power to the leds the more you add, but would increase effeicency and might be just as bright...

I just modified my 3led 1AA today. Waiting for the thermal epoxy to cure. I took it apart, and put a luxeon in it! It should be brighter, and throw farther. Can't wait for tommorow when I solder it up and assmeble the reflector into it. (using a minimag reflector). I might end up keeping it, as I thought about selling it when I changed my mind on my primary EDC. But now I might change my mind again! /ubbthreads/images/graemlins/smile.gif Depends how much I'll use it. Can't wait!