Help with IR LEDs: Powering, Wiring & Resistor Questions

[MOzebra]

I have a project in mind that I need help with IR LEDs. I'm not an electricity expert; actually, I have almost no experience in electronics. I had an idea for a project and now I'm just trying to make it work. I will need to power a number of IR LEDs at one time for a continuous period. Is there a way to figure out how much power I will need per IR LED? Also, what type of resistors will I need and how will I need to wire it inline with the LEDs? Does each LED need a resistor or can I run a few LEDs off of a resistor?

I appreciate your help and I apologize for my lack of expertise on the matter.

 

[fss]

You can take a look at what this guy did; it seems like it's fairly applicable to your situation.

http://alignment.hep.brandeis.edu/Electronics/A2045/M2045.html

 

[MOzebra]

Ok, I hate to admit it, but I'm kind of lost with that. I'll look over it again tomorrow when I get the chance and hopefully it will make more sense. I was planning on wiring everything up inline. Would it just be easier to make a board and wire them all up to the board?

The IR LEDs won't really serve a purpose other than just turning on.

 

[mheslep]

Ok, I hate to admit it, but I'm kind of lost with that. I'll look over it again tomorrow when I get the chance and hopefully it will make more sense. I was planning on wiring everything up inline. Would it just be easier to make a board and wire them all up to the board?

The IR LEDs won't really serve a purpose other than just turning on.

Forget about the IR aspect for the moment, a diode is a diode. You'll need to know the rated voltage drop across your LED and rated current. Then see something like this:
http://members.misty.com/don/ledd.html

 

[MOzebra]

mheslep: That makes a little more sense. I think I'm starting to catch on. What is the difference between putting LEDs in a series and parallel to each other as your link describes in the last two paragraphs?

So let me see if I've got this correct...according to that link, if I used LEDs that were 1.7 volts and a battery that is 12 volts, I should run like 5 LEDs off of that power supply? (80% of 12 volts is 9.6 volts. 9.6 volts divided by 1.7 volts is 5.65 LEDs.) Would that be the correct way of figuring that out?