Go Back   Aquarium Advice - Aquarium Forum Community > General Aquarium Forums > DIY Projects
Click Here to Login

Join Aquarium Advice Today
Thread Tools Search this Thread Display Modes
Please support our sponsors and let them know you heard about them on AquariumAdvice.com
Old 02-17-2006, 02:36 PM   #31
Aquarium Advice Addict
Wizzard~Of~Ozz's Avatar
Join Date: Jan 2005
Location: Ontario, Canada
Posts: 2,039
Send a message via MSN to Wizzard~Of~Ozz
If you don't have the led's yet, try Ebay, you get a much better price (11$ for a hundred, or 6$ or so for 50) and they come with resistors rated for 12VDC... most eletronics shops try to gouge you for 2$/led and 1$/resistor.

The value of resistor depends on the DC adapter voltage. the coles notes breakdown for the average value can be calculated by.

(InputVoltage-.7)/.03 = Resistor value.

So, assume 12 volts in.

12 -.7 = 11.3 / .03 = 376Ohms , or the nearest common resistor which is greater (probably 380Ohm)

Most 12v adapters put out 13.8v, so putting it through the works it is 470Ohms ~

The resistors colour codes are
0 - black
1 - brown
2 - red
3 - orange
4 - yellow
5 - green
6 - blue
7 - violet
8 - grey
9 - white

The breakdown of the bands are
moving towards the gold/silver band (tolerance, gold = 5%, silver = 10%)
first band = first digit
second band = second digit
third band = multiplier (unless a 4th band is present, in which case, this is the 3rd digit, the next is the multiplier. But typically you won't see this)

So for example, the resistors that came with my LED's rated for 13.8v are

yellow violet brown gold
4 - 7 - 1 - 5%
using what was said above.
47 * 10^1 = 470Ohms at 5% tolerance (+/- 5%)

The ones in this example are
red red brown gold
2-2-10^1 5%
or 220 Ohms.

And the adapter he was probably using is a 6v DC adapter.

Hope it's not too winded, I just think it's better for people to know how to calculate the right resistor rather then assuming the same resistance is used for every transformer.

For those that care beyond that where I got those numbers..

.7 is the voltage that the LED uses
.03 is the maximum current that can travel to the LED (.03a or 30mA)
the formula is basic ohms law. *Voltage divided by current = resistance*, resistance * current = Voltage and Voltage / Resistance = Current

You subtract the .7 volts from the source voltage because this is the voltage drop across the LED. The remainder must be dropped across the resistor that must have 30ma travelling through it. Knowing this, you can divide the remaining voltage you need to drop by the 30mA you need to flow through to get the resistance. This formula is fundemental to electronics.

120 Gal SW, 150lbs Prem. Fiji, 23Gal Sump, 2x250w 15K MH, 4x65w Actinic
3 x Halichoeres Chrysus (1 surfed), 3 x Nemateleotris magnifica, 1 x Centropyge bicolor, 11 x Scarlet Hermits, 6 x Zebra Hermits, 40 x Astrea Snails, 6 x Nassarius Snails, 3 x Cerith Snails
Wizzard~Of~Ozz is offline   Reply With Quote
Old 02-17-2006, 02:45 PM   #32
Aquarium Advice Activist
Join Date: Jan 2006
Location: Miami, Florida
Posts: 120
Thank you Wizard for that lengthly but very instructive answer. I had taken some many years ago some electronic classes and remembered a bit about the resistance table, but not all of it, so really and trully thank you, and I'll be checking Ebay for the leds as well.

Ill try to post some pics after my NEW project is complete.
I have a new 29 gall tank that is dieying for some attention. ( don't worry, it has not been set up yet, no fish are in danger... just my lower back! )

**** it! Give me Full Power,
Lets have some fun boys, time to test our metal!
MiamiFishy is offline   Reply With Quote
Old 04-25-2006, 11:19 PM   #33
Aquarium Advice FINatic
Join Date: Feb 2006
Posts: 820
Nice post RLG2182.well done.

I'm going to do this in some fashion and will probably buy the supplies online tonight.It looks to good and is to cheap not too imo.

A question or thought though....

What would be the down side of mounting the leds inside the bulb housing itself....like the standard strip that comes with start up kits.I realize that the leds would also light up the inside of the strip housing,but wouldn't most of the light make it to the tank without the "beam" effect?

Any one try this or know why I shouldn't?

50g tall fw planted at .6wpg
29g fw planted at 1.2 wpg
10g fw planted at 3 wpg cf
SCFatz is offline   Reply With Quote
Old 08-11-2006, 06:22 PM   #34
Aquarium Advice Apprentice
Join Date: Jul 2006
Location: the bay area
Posts: 34
led lights

that looks so cool one day ill do that hopefully
norolo is offline   Reply With Quote
Old 01-22-2007, 06:44 PM   #35
Aquarium Advice Addict
7Enigma's Avatar
Join Date: Dec 2005
Location: Havertown, PA
Posts: 2,913
Can anyone comment on another site that has a kit like this? I am completely stupid when it comes to DIY but I really would like to give this a shot! Thanks!
Main (20g) - A throng of guppy and platy, Pressurized CO2, Ferts, All Live Plants (Very old pic, new one forthcoming)
7Enigma is offline   Reply With Quote
Old 04-04-2011, 01:40 AM   #36
Join Date: Mar 2011
Posts: 138
what resistors did you use and what is the output of the ac adaptor?

Humanis1993 is offline   Reply With Quote

diy, light, lights

Please support our sponsors and let them know you heard about them on AquariumAdvice.com

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Documentation: 40 gal sump project ***dial up sensitive*** RLG2182 DIY Projects 37 11-05-2012 06:09 PM
DIY MoonLights Liquid_Pyro DIY Projects 12 05-15-2009 11:25 AM
DIY Moonlights. SparKy697 DIY Projects 26 03-27-2007 10:24 AM
DIY Moonlights Dewey DIY Projects 2 07-02-2005 02:08 PM
DIY Moonlights Joshsmit56001 DIY Projects 4 12-03-2003 05:09 PM

» Photo Contest Winners

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -4. The time now is 01:27 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.