Thread: Led Help

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I want to do some things with led's and I was wanting to know if someone could help. I saw somewhere that someone was making led spotlights how do you make them and materials do you need and what kind of led do I need to use? I was wanting to make them without using any resistors since it seems that they are kind of complicated well any help would be appreciated thanks

I posted some pics of the LED spotlights I made for prop lighting this year. It shows wiring for 2 and 3 LEDs. The tube housing is 1" OD plastic. The LEDs are all high output (650 mcd), 3 volt, with a 20 degree beam pattern. The tight beam works well for spotlights. The 2 LED version requires a resistor if you want to use a 9 volt battery, but the 3 LED model doesn't really need one. For 2 LEDs of this type, I used a 150 to 220 ohm resistor, depending on how bright I wanted the light to be. The holder is made from insulated 10 gauge solid copper wire. The pics are here:
http://halloweengallery.com/displayimage.php?pos=-3119

Here is the tutorial you seek about LED spotlights:

http://www.halloweenforum.com/showth...ight=spotlight

Another discussion is here:

http://www.halloweenforum.com/showth...7&page=1&pp=10

My thoughts on being underwhelmed at the result are included here:

http://www.halloweenforum.com/showthread.php?t=9844

Do some research and make you own decision.

It's true that LED spots are not as effective as a pinspot for illumination over longer distances. I use them for very localized lighting, such as uplighting on groundbreakers, grave markers and the like. I like the purity of the color you get with LEDs and the ability to highlight individual props, sometimes with a couple of different colors. The small assemblies are easy to hide just about anywhere in the graveyard, too.

These are the leds That i ordered
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7571938067
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7571943055
how many can i run off of a 9v or a AA or a few AA what are my options and are these ok leds

Those LEDs are fine. 5000 mcd will be bright enough for your spotlights... you'll get the idea of what/how much they can illuminate when you start playing with your setup (as the guys mentioned, above).

Your spotlights will probably house 2-4 LEDs, so a 9v battery will work great. Whether you wire them in series or parallel will determine how long the battery lasts, and determines the necessary resistors. Check out this link:

http://led.linear1.org/led.wiz (for your project, "forward" and "reverse" current are the same thing)

Good luck!

for risistors should i just pick them up at radio shack even though they are more expensive or order them off ebay and wait on them maybe ebay may have a variety pack with all kinds of them in it ill have to check i just dont like waiting much

Ok here is my question i ordered these leds
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=7571943055
and these risistors
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN%3AIT&rd=1
ok so my question is on that calculator thingy i typed in 6 leds running off of a 9v battery and it said i needed a 83 ohm resistor so do i need to order some more or whati want each led light to get the same amount of power like at least 3.2 i think so they are all bright because i have a ton of 9v batteries so changing them is not a prob i also bought some red leds
http://cgi.ebay.com/ws/eBayISAPI.dl...item=7571938067
am i going to need different resistors? i bought 3 sets of those resistors which is over 600 of them for like 6.48 so they were cheep!! Also i couldnt find anywhere that had some easy to understand pictures of series and parallel circuit i know what they do just not how to do them. Also I have never soldered before i am waiting on the solder gun and leds and heat shrink tubing and battery snaps so i cant practice any tips on anything?

ok i changed some stuff i think i got wrong the first time

Source voltage=9
diode forward voltage=3.2
diode forward current (mA)=30
number of LEDs in your array=4

Solution 0: 2 x 2 array uses 4 LEDs exactly



The wizard says: In solution 0:
each 100 ohm resistor dissipates 90 mW
the wizard says the color code for 100 is brown black brown
the wizard thinks 1/4W resistors are fine for your application
together, all resistors dissipate 180 mW
together, the diodes dissipate 384 mW
total power dissipated by the array is 564 mW
the array draws current of 60 mA from the source.

so is a 100 ohm the same as a 100k that i ordered