LED questions

Discussion in 'The Projects Forum' started by Kane, Aug 5, 2010.

  1. Kane

    Thread Starter New Member

    Aug 5, 2010
    13
    0
    I am very new to building any type of circuit beyond putting batteries in a flashlight. Before bugging y'all with my question, I searched this as well as other forums and did not find an answer.

    I want to build a few big aquarium lights similar to the grow lights one sees on ebay. The first thing I did was buy some LED's off ebay, clean some old PCB's from computers (hard to find the long skinny ones new so I cut my own) and place two rows of 30 LED's all connected to 2 leads (all the positive on one lead the negative on the other) Then I connected it to an of the shelf 3.5v transformer from a cordless phone. It worked fine.

    Then I started looking on forums for how to do a much bigger light and read how one cant do what I did without resistors and this or that other component and now I'm all confused.

    I want to build three lights each using 100 white 5mm 3.5v LED's and 50 of the same in blue and 50 in red 1.5v LED's. The three colors will have their own on/off switch.

    Real simple, nothing proprietary. Just dont see why I should spend over $500 each for something I can make for less than $50 each. I already have the housings. Can someone explain the HOW (using simple idiot terms) or even give me a basic diagram?
     
  2. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
  3. Kane

    Thread Starter New Member

    Aug 5, 2010
    13
    0
    Wow! That was fast. That wizard is simply perfect. One question though.... How could I use a computer power source (ATX or AT)? What would I use to regulate the needed current? Or more accurately, what current do I need to input for the three different lighting strips? One has 100 3.5v LED's, one has 50 3.5v and the third has 50 1.5v LED's.
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,764
    2,534
    The concepts are explained here.

    LEDs, 555s, Flashers, and Light Chasers

    Wizards have some major problems, notably in the area of common sense. As the voltage drops of the LEDs (Vf) get close to the power supply voltage they tend to blindly give answers that are pure nonsense.

    You are much better off learning how LEDs actually work.
     
  5. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    The resistors limit the current, the computer PSU should have more than enough capability. You might have to do something to make the PSU work without the motherboard, search for ATX power supply hacking.
     
  6. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
    969
    Just a comment... If this is for a reef (saltwater/corals) those are not the LED's I would choose as the color of the LED's is much more important than just regular lighting so the fish can see :)
     
  7. Kane

    Thread Starter New Member

    Aug 5, 2010
    13
    0
    I'm both a marine and freshwater aquarumist. I agree the lighting won't be sufficient for marine use but I have several very large freshwater tanks that cost alot to light. I just need to supply some lighting for veiwing pleasure as they are mosly nocturnal catfish (hence the red lighting). The white and blue allow veiwing of the substrate and tank furniture.

    After reading up some here on the forum I can see that while I definately will save some money fabricating my own, it's gonna take some learning so as to do it correctly. It'd be a lot easier if electronics came with the schematic attached to the inner case cover like the old days.
     
  8. Kane

    Thread Starter New Member

    Aug 5, 2010
    13
    0
    Ok, I've sourced two ATX PSU's and found several sites clearly explaining how to convert them to fit my needs. Waiting on the parts to do so to come in the mail.

    I've been reading, then re-reading over and over, the materials located in the links y'all have suggested. Then, just when my head is really itching, I re-read it all again again. Maybe I've gotten too old or something, hell, I'm only in my 40's. This stuff is harder than learning a new language.

    Learning the symbols on the schematics seems to be an important step. But what is the backwards S with the arrow on the tip symbol next to every LED? I can't find that symbol in any listing.

    Now, I can solder the heck out of anything. I'm a serious hobby enthusiest and have done from lead bodywork to miniature metalcraft and have very high quality equipment from butane guns to resistance units. So, doing the work is something I'm capable of. Understanding it......that remains to be seen.

    Now, I'm going to continue to try to grasp all this but in the meantime if anyone would like to draw up a diagram/schematic for me I'd be real appreciative. I know that would be time consuming and I should learn to do for myself so I'm not going away all mad if no one jumps at the opportunity.
     
  9. Kane

    Thread Starter New Member

    Aug 5, 2010
    13
    0
    BTW....my basic shape is four rows of 50 LED's. 1st row is white, 2nd is blue, 3rd is red and 4th is white. I may double this in width and possibly in length as well. Each color will operate off it's own on/off switch.
     
  10. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    The arrow thing is just to show it is an LED rather than a normal diode. Often the symbol uses 2 arrows pointing away from the diode, which means the same thing.
     
  11. Kane

    Thread Starter New Member

    Aug 5, 2010
    13
    0
    Thanks. I saw the 2 arrow symbol. I appreciate the clarification.
     
Loading...