IR led help please.

[orionlion82]

kinda got a snag with my $30 nightvision project.
and its all that much more difficult because i cant see what im working with and i cant get my head around the numbers...

ive got about 5v to work with. (might be as high as 5.5)
i have 15 IR led's (dont have to use them all but several might be good)

i can draw up to 100Millyamps, but an unknown device consumes an unknown amount allready. i MIGHT be able to get away with up to 500 millyamps
(read this) but i would like to stay within spec.

i would also like to design my circuit to draw the least current for the most amount of light in the smallest size...

Voltage? glad you asked. 1.2 to 1.7 @ 50 millyamps. per unit.

it allso lists the radiant power at 100 milliamps as 10 to 16 milliwatts.

i have no idea how bright that is.
i dont even know how hard i should push them at what Ma...

im thinking of just hooking 8 in series with no resistor, but thats 400 millyamps right there! right?
(and realistically i probably want to go with 5 or 6 to keep from washing out close up objects)

where do i even start with this?
i dont even know how to approach it.

ive only dealt with the 3V led's at 12V and thise numbers dont work, heh.
tia

EDIT: all the led calckulators ive been using come up with about 100 or even 200 milliamps depending on if the numbers oncy shift slightly? i have to be approaching this the wrong way...

 

[frenzee]

So, you are trying to drive IR leds from a USB power source?

 

[orionlion82]

So, you are trying to drive IR leds from a USB power source?

yes thats correct. these are very different animals than the regular ones.

i cant tell how many i need because they are rated in Milliwatt intensity.

how bright are they?

do i need 2 and pull 200Ma with them total?

do i use all 15 at 30Ma each and risk washing out my images?

what i need to know is how much is enough -

suppesedly they are rated for 50Ma and that sounds high - but i am used to 3.3V so being higher makes sense with the lower voltage.

now yall, heres the problem. 100Ma just on one of these puppies?
i imagine thats going to make alot of output if it were visible.

or not? maybe 50Ma is not much at all.

here are the ACTUAL specs now from a cap.

 

[orionlion82]

TTT.
i would really like to get a feel for the output of these things, any help appreciated. tia.