After months of study, and care to procure the material is finally ready for the new DIY LED ceiling light.
As always I will try to make a mini guide for those who decide to try their hand at building a similar project.
First some theory
LEDs
Definition
LEDs are light emitting diodes, tecnicamentente you just know that the current flows only when the LED is positioned with the correct polarity.
There are a wide variety of LEDs, but essentially all fall into the categories low power
and high power
(There are also others who do not take into account). All high power LEDs need to work properly with a constant supply current. This power will be needed in order to guarantee specific drivers and appropriate processor (there are drivers that integrate these two features) Choice For aquarium use LEDs that serve our purposes are the high power LEDs. High power LED because compared to traditional consumption and clearly have a much higher light. Specifically I used for my project led by 3w.
The first thing to note when choosing a LED in general and an electronic component is the datasheet. This document contains valuable information that allows to know the details of the component, such as voltage, temperature and so on.
One of the parameters to which place greater attention is the ' efficiency expressed in lumens per watt. Trivial explained in words is the amount of light that is emitted by the LED for each consumer wat.
higher this ratio, the more light we will have the same consumption.
Another parameter is the choice of LED color temperature and even longer wavelength. As you know light is made up of different colors, the color components in the presence of some lengths determines the final color result.
Depending on the needs of bred animals is preferable to choose certain wavelengths than others. Only some of these are visible to the eye .. for example, infrared is not visible but it is the component that produces heat. An example of the light spectrum
LEDs that we choose will have almost nothing to a component so that's why our infrared LEDs do not produce heat to the tank.
said pre spectra provide cover to help corals I chose to use LEDs so-called "royal blue", "blue" and "cold white" (cool white).
Now is the time to choose the brand and the series. The proposals are so many on the market but the brand that currently produces the most efficient LEDs in lumens per watt is CREE. There are different sets of LED XR-E, XP-E, XP-G each series has its distinctive features. My choice fell on 3 types for various reasons linked to the price, availability and efficiency trade-off between angle, etc. ..:
CREE XR-E BLUE
CREE XP-G R4 COLD WHITE 7000K
CREE XP-E ROYAL BLUE
Here you can see the spectrum of XP-G
A parameter to consider when choosing a LED is the angle of emission. This determines how open will the beam of light. The more the cone is large, the light will have less penetration while more widespread. The angle can always be corrected by using the appropriate lenses.
Cone of Cree XP-g
Last note for the selection of the LED is to get LEDs mounted on PCBs, as given the small size would be impossible to weld.
drivers
Although a 3W LED is classified as not necessarily have to eat .. 3w Watts are in close correlation to the current through the LEDs, in Amperes.
Suppose, for example to power a LED with a current of 700mA. Knowing that the LED requires a potential difference of about 3v, we would have a consumption of about 2.1 w (P = I x V). Here is a link up some useful hints for saving energy
Clearly a driver will have a "domestic consumption", which will add to the consumption of the entire system. When selecting the driver it is important to first understand the datasheet of the LED that we have chosen to current need.
closer we get to the max we have supported more light, but lose efficiency at the same time! . Should be paid so much attention to this ... what is the point to drive an LED that produces 1A 100lumen watts when driven at 500ma would 150lm watts? Rgionateci a second ...
Another key aspect is the heat by the LED, if it is true that the LED does not emit heat as infrared does not produce is not true that it does not get hot!
greater the current passing through it, the more heat that will necessarily be dissipated.
In my case I have identified 700mA in a good compromise between efficiency, heat and overall brightness.
Dissipation Heat dissipation can be achieved by putting in communication the base metal of the PCB with a heatsink made of copper or aluminum. These materials have the ability to conduct heat very well so that leaves the body heat of the LEDs and ends between the fins of the heatsink. To further improve the all of the fans will allow air to cool the fins of heat sinks.
To ensure good contact between the PCB and the LED heat sink using the thermal paste.
Now that we have all the elements we are left to do is assemble it all.
A short shopping list: Led
choice in the number and color (mine has 100 LEDs which 60 white and 40 blue)
Driver calibrated in the current and the number chosen to feed into the LEDs (I used 5 Driver AC-> DC 700mA each capable of driving up to 20 LEDs)
Cooler in bars or individuals led
If we decide to put the drivers in the ceiling will be sufficient to bring PLAF up to the wires from the AC. If instead we opt to put the driver out, you will need to get to the LEDs, the positive terminal of each driver and a mass shared. In the first case I recommend IEC connectors pc, while for the second connectors 8-pin cable with sufficiently thick to ensure the flow of current.
12v Fans for cooling by 80 or 120mm
Protection grill for fan
transformer 12v to the fans (more than enough 1A)
The rest of the material are the parts of the body that depends on what type you use wood, Plexiglas, etc. ..
Tools
We will definitely
Drill
soldering tip end with solder
Tester Jigsaw
scissors pliers electrician
various
Any advice on installation and on the main problems you might encounter.
The LEDs are connected in series on the driver and never in parallel.
Problems
1) Some LEDs do not light
probably do a few laps because the current alternative "jumping" led those ... considered that the heatsinks are excellent conductors ;-) To diagnose this problem you can do so: tester OHM position and measure the resistance between cable and bar in the immediate vicinity of the cable. If the tester gives you a number other than 1 then there is current flow and have found the problem.
2) No led lights
Probabilemnte no current flows. Confirm with the tester in place of the Ampere and putting the + driver to a pole and the meter unless the meter in the first led. If you do not pass current from 0, then somewhere in the circuit is interrupted. It could be a
led burned or incorrect welding. To find the problem: get a piece of wire and jump the LEDs one at a time, linking always to a + -. When you see all the LEDs light up except one have found the problem!
