sambo

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Introduction:

The purpose of this thread is to explain in detailed layman's terms the steps involved to make a simple LED light. You don't have to be an electrical engineer to make one of these lights. With a little effort, practice and some basic knowledge of electricity anyone can make an LED light fixture. This project is a good way for anyone with some reservations or hesitation about pulling the trigger on a large LED project to get their feet wet on something small so that they can get the basics down before diving into something major. I am by no means an expert on electricity and this is only my second time soldering anything. I'm planning on doing a large scale fixture for my 75 gallon in the future.

IMBLIND.jpg


Step 1: Gathering supplies

Tools -

Soldering iron ? get a good one from weller, I did not do this and I am paying for it now! This one I am using is terrible.
Sponge
needle nose pliers
toothpicks or paperclips
screwdriver ? I needed this, you may or may not
heat gun or hair dryer (cigarette lighter will work in a pinch)

supplies.jpg


Materials -

First a little background on how LEDS are typically configured for an aquarium as this will help you to understand how to pick your materials. Most people are using a DC power supply of some kind and connecting a number of drivers to that and then connecting strings of LED's in series which means connecting the negative of one to the positive of the next in a 'string'. The amperage of the power supply will tell you how many strings you can run and the voltage will tell you how many LED's it can power on each string. I suggest you click the links in the below sections to gain a better idea of what I am explaining as they are mostly to data sheets which are important and you will be referring to them when planning to do a larger project.

LED ? The LEDS you choose will be based on your project. I chose 4 white Cree XPE from dealextreme for mine as I wont be needing blue because this will be a fuge light. The data sheets for these LED's can be found at Cree's website. Choose Your LED's carefully as they are not all extremely bright like these. Look for the correct bin. You'll want the 'luminous or radiant flux group' section of the bin to say Q4 or Q5 for white. The royal blue color is great for actinic and makes coral color pop. You'll want your LED's to come pre-mounted because when they are unmounted they are very small and impossibly hard to solder for a novice. Here are some good websites to buy the kind of LED's and supplies we will be needing.

http://www.ledsupply.com/
http://www.dealextreme.com/
http://www.cutter.com.au/

led.jpg


Driver ? You need a constant current driver to run these LEDs. I don't want to get into all the reasons why you need this, just know that if you try to not use a driver your LEDS will not last very long. For this project I chose to use a regular non-dimming 1A Luxeon buckpuck from ledsupply. There are for clearly labeled wires coming out of it, two (+ and -) connect to the power supply and two (+ and -) connect to the LED string.

Power Supply ? For this small project look for one of those big black square plugs that most all of your electronics uses. I chose one that was for a cable modem. Look at the label of your power supply. The amperage will tell you how many strings of LED you can run from it and the voltage will tell you how many LEDs it can power on each string. Just add up the voltage of all the LED's which run at 3.7V each. Since my buckpuck is 1A and must have an input voltage between 5-32 V my 1A 15V DC power source should work fine for 1 string of LED running at 1A and since the forward voltage of each LED is 3.7V I can power a max of 4 LEDs on the string because the fifth would put me over 15V. For larger projects, get bigger power supplies (like for computers) which generally can do 24V and more amps lets say for example 8A, which would allow you to run 8 strings at 1A and 6 LED per string for a total of 48 LED .

powersupply.jpg


Heat sink ? You will be needing a heat sink of some kind. This is what you mount the LED's to. These kinds of LED get very hot and can damage themselves if they get too hot. Copper or aluminum work great for this. A small piece of aluminum will work fine (can be found at home depot). I chose a processor heatsink and fan because I already had it in a pile of computer junk. For a project this small it really doesn't matter what you choose so long as there is something there dissipating the heat. For larger projects, the heatsink becomes much more crucial. You should also give some thought to how you will be mounting the heat sink over the tank and possibly how you will be shielding it from saltwater. These concepts are not covered in this tutorial.

heatsink.jpg


Other materials -
Arctic silver thermal epoxy ? I chose to use this as it is the easiest method of mounting the LED's while and is made for heat transferring situations like this.
60/40 rosin core solder ? the appropriate solder for the job
22awg solid copper wire ? thin and easy to work with. Any thin wire works though, I used speaker wire on my first led project.
Heat-shrink tubing ? for insulating wire connections

Step 2: Mounting the LED's and driver

First make sure your heat sink is clean and has ample space to mount your LEDs. Mine had this copper bar on the bottom and under it was a bunch of thermal paste that I had to clean off with some tissue paper.

heatsinkprep.jpg


Decide how you want to arrange the LED's. Take note of where the + and ? soldering pads are on the stars because we will be soldering small bits of wire to these to connect the LED's in a string.
There are usually two +'s and two -'s on each star. Either will work fine and you will not use all the pads.

Take into account that you will be connecting the positive lead from the driver to the positive on the first LED. Then you connect the negative from that first LED to the positive of the next one and so on until they are all connected with the negative of the last LED connected to the negative lead from the driver so to make it easy, try to make the pads line up.

arrangement.jpg


Pick an out-of-the-way spot for your driver such as the back or side of your heat sink. These heat up a bit as well so you can use the thermal epoxy to glue it. Just make sure the wires can reach what you have chosen as your first and last LED. Superglue does not work.

Take your time with this step and plan out what you are connecting and where. You want the pads to be close but don't put them so close that it is difficult to bridge the connections with a small bit of wire.

The Arctic silver thermal epoxy is a two part epoxy. Mix up equal parts of it on a paper plate or some paper using the toothpicks or paper clips. You'll only need a tiny glob of each. I made one of my gobs too big and then had to add more of the other part and ended up with a lot of waste.

epoxymixing.jpg


After mixing, put a small amount where you want the LED to attach and press down a little. You only need a tiny amount of epoxy to attach them. I actually tried to remove one and that was definitely a no-go. This stuff is very strong so take your time and make sure you do it right the first time.

ledepoxy.jpg


Attach all the LED's and drivers this way to your heat sink of choice. Let the glue set for about 5 minutes before soldering to the stars.




Step 3: Preparing the wires

Steps 3 and 4 are going to be repeated until you have the entire string connected. Do step 3 (Measure, strip, tin) then step 4 for each connection you have to make. Do not cut all the wires and then tin and connect them because you will confuse yourself, just do one connection at a time.

Plug your soldering iron in so that it starts heating up we will be using it for the next few steps. Also, wet the sponge (not sopping wet, just dampen it) we will be needing that as well.

Measure the wire and cut it. Do not use more wire than you need. It is best to make the wires as short as possible.

measure.jpg


Strip off some of the insulation. Do not strip off more than you need to. You see these tiny little pads on the LED stars? You will only need bare wire of about the width of one of those pads. Use your dykes or needle nose pliers to accomplish this. Just squeeze the cutting blades of your tool down a bit and release repeatedly while rotating the piece of the wire. This will score the insulation which you should be able to tear off with your thumbnail.

wireprep.jpg


Disclaimer: I am an extreme novice at soldering and barely have the skills to do this project. I know there are ways to get the solder much much neater but that is not our goal here. This tutorial is written by someone who knows only the basics of soldering and for people with no experience doing it. Also, THE SOLDERING IRON IS VERY HOT DO NOT TOUCH IT OR PUT IT DOWN ON ANYTHING THAT CAN BURN BECAUSE IT WILL BURN IT!!!:lol:

Now, we will be 'tinning' the wires which is basically just getting some solder on the bare tips we've made. This is how I did it, look here to find the correct way. To do this pick up your (hopefully hot by now) soldering iron and touch the solder to it. You will see the solder melt instantly and appear to become part of the tip, its not. Quickly rub the tip on you sponge and you should see the solder get shiny and start to look something like the T-1000 from terminator 2 (liquid metal). Then apply this to the tip of the wire by touching it to the bare end of the wire. MAKE SURE YOU HOLD THE WIRE WITH THE TWEEZERS OR NEEDLE NOSE PLIERS BECAUSE THE IRON IS INCREDIBLY HOT. You should only need a tiny bit of solder on the tip of the wire, just enough to turn the exposed copper silver in color, if you get more than you need on the tip, no big deal. Touch the iron to it briefly and some should stick to the iron. I'm sorry i don't have better pictures of this but I don't feel comfortable handling the camera and the soldering iron at the same time so this one will have to do.

wiretinning.jpg


Step 4: Making the connections

Now we will be connecting the LED's. First get some solder on your iron like we did for tinning the wires (apply solder and wipe on sponge). Then touch the iron with solder onto one of the pads so that you get a little gob of solder on it. Do this again for the other pad you are connecting with.

ledsolder.jpg


Pick up your tinned wire from last step with tweezers or needle nose pliers. Hold the wire in place with the ends touching the two pads that you are connecting (with the pre-applied gobs of solder) and touch the iron to it. Be careful not to touch the iron to the LED itself because that will ruin it. You should only need to keep the iron there for a split second to melt the solder. You can then release the wire and make the other connection the same way, just briefly touch the iron to the solder and the tinned wire to connect them.

conections.jpg


That wasn't so hard, was it? Now repeat steps 3 and 4 until you have connected all the LED's, negative to positive, unlike the above picture. can you spot the error? :tub:

Tin the ends of LED leads from the driver and connect the positive lead to the positive of your first LED and negative to the negative of your last LED.

allwiredup.jpg


I figured out during the next step that I had made some connections wrong.:iamwithst

Step 5: preparing and connecting the power supply

Your power supply probably has one of these round proprietary connectors on the end of the wire that connects to whatever it was meat for. Just go ahead and cut that connector right off.

psplug.jpg


Divide the wire down the center and strip about ? to ? of an inch of the insulation off just like we did before. Be careful though, the wires are probably stranded, which means instead of a a single wire inside the insulation, there will be a number of thinner wires inside there. This is to make the wire more flexible. After stripping the insulation off, twist the bare wire together.

psperpped.jpg


Now you will need to determine which is the positive wire coming from the power supply. Usually this is the one with the white strip running down the side of it. If you can not figure out which is positive don't worry, just pick one and if it doesn't work, switch them. Twist the positive (or what you think is positive) of the power supply with positive lead from the driver. Do the same with the negatives and then plug the power supply in. Be careful not to be looking at the LED's when they fire. You should have light.

IMBLIND.jpg


If you don't have light, check all the connections. Make sure the LED's and driver are all properly connected. Mine didn't work at first because I had connected on of the LED's wrong. If all the connections are correct and it still does not work you probably have a bad LED, driver or power supply.

Once you have determined that you have a working light and that your connections are sound its time to permanently connect the power supply and the driver.

Get out your heat shrink tubing and locate two small ones and a large one. Slide the large one on the power supply wire and the two small ones over the individual positive and negative wires. Make the connections again and slide the small shrink tubes over them and shrink them with your heat gun or hair dryer. Then slide the large tube over the smaller ones and shrink that.

shinkingthetubes.jpg


Conclusion

That's it! You're done! Well, pretty much done. Now you'll have to figure out a way to mount it and to keep saltwater away from the soldered connections which is not covered in this tutorial. I'll be mounting mine to the inside of my stand over the fuge with some paper providing a screen because when I see this thing operating, I get dots like from a camera flash.

Hopefully, after reading this tutorial and making a small, single string LED project, you will have gained the knowledge necessary to build a large scale LED fixture for a larger aquarium. Happy reefing!
:givebeer:
 

sambo

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PHENOMENAL WRITE UP. I am trying very soon and it's great to read about all the DIY's so there's less chance of me screwing up. This one is very comprehensive. Appreciate it much!

very nice !

Thanks!

what was the total cost for materials on this DIY project?

Its tough to quantify. The buckpuck was $15 and the LED's were around $6 each and I already had everything else laying around. You can make a MUCH cheaper fuge light but the purpose here was to practice a little bit before starting a larger project.

great post sambo, thank you very much.
not a problem. I was happy to do it. I may do something like this again for the larger one, whenever I get the funds together and work all the kinks out.
 
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DCG1286

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Great write up ... definitely following along for a larger project ... have been very curious to try LED's over my 120. :)
 
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sambo

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that is sweet. any way to see it over the refuge if you have gotten to that point. great work on the write up.

Thanks. I still have to go buy a 10g and drill it and all that to re-do my fuge. My fuge broke when I moved from copiage to east meadow last month. One of my helpers put a bit too much pressure on the pipe coming out of the bulk head and cracked the tank. :irked:

I have a clip on type lamp that i was thinking about gutting and fitting the heat sink inside of it. :shhh:
 

bruma bull

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leds

this looks awsome, one question tho, are these leds wired in series? because if one bulb goes out the whole fixture wont work, i think a paralle circuit is the way to go
 

azazel

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Hello from far, far away country ;)

First of all sorry for my english - please forgive me ;), I'll do my best to write correctly.

@sambo - i see, that You connected your led's directly to power supply without any current limiter. That's really bad. Led is light source with dynamic resistance - because of that you must limit the current that flows by the leds. If you don't - leds will be destroyed.

Cheapest way to do it, is the resistor, connected between led (string of led) and power supply.
This resistor can be calculated : R=U/I U means the power supply voltage, I mens the Led nominal current.

Correct is R = U(p.supply) - U(voltage dropped on leds) / I (led)

In Your case, only that power suplply used by you has maximu current of 1A, the leds still work, but they produced a lot of heat. If someone will use a bigger power supply unit - 2, 3 - 4A, nothing will help, any radiator is not in the position to get the heat away from the led structure and .... led is gone.

So, in Your case we have U=15V, U(dropped on leds)= 4x3,7V = 14,8V and the safe current for this led is about 700mA = 0.7A (not 1A - check the pdf file and look at lifetime curve)

next we have - R=U/I : R=15-14,8/0.7 = 0.2/0.7 = 0.28R The closest value of resistor possible to buy in electronic store is 0.27Ohm - quite good.

You should put 1 resisstor of 0.27Ohm, and minimum 2 Watts to every led string to save your led.

of course there are better but not so easy ways to limit leds current, but this is most simply. Remember - connecting led directly to power source is very danger due to dynamic resistance of led - it is "visible" as "short-circuit". Both led and/or power supply can be destroyed in that case.
 

sambo

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this looks awsome, one question tho, are these leds wired in series? because if one bulb goes out the whole fixture wont work, i think a paralle circuit is the way to go

Yes, they are wired in series and you are right that for this project a parallel circuit would work better. For a large project though, where you would have multiple strings, parallel circuits are not ideal. From what I was told, if you connect a few parallel strings together on a driver (a larger driver than used here, like a meanwell type driver) and one LED fails, it will overdrive the other string and probably fry all of the LEDs on the other string. I'm just an amateur at this and really don't know everything, I'm just following what I've read.
 

sambo

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Hello from far, far away country ;)

First of all sorry for my english - please forgive me ;), I'll do my best to write correctly.

@sambo - i see, that You connected your led's directly to power supply without any current limiter. That's really bad. Led is light source with dynamic resistance - because of that you must limit the current that flows by the leds. If you don't - leds will be destroyed.

Cheapest way to do it, is the resistor, connected between led (string of led) and power supply.
This resistor can be calculated : R=U/I U means the power supply voltage, I mens the Led nominal current.

Correct is R = U(p.supply) - U(voltage dropped on leds) / I (led)

In Your case, only that power suplply used by you has maximu current of 1A, the leds still work, but they produced a lot of heat. If someone will use a bigger power supply unit - 2, 3 - 4A, nothing will help, any radiator is not in the position to get the heat away from the led structure and .... led is gone.

So, in Your case we have U=15V, U(dropped on leds)= 4x3,7V = 14,8V and the safe current for this led is about 700mA = 0.7A (not 1A - check the pdf file and look at lifetime curve)

next we have - R=U/I : R=15-14,8/0.7 = 0.2/0.7 = 0.28R The closest value of resistor possible to buy in electronic store is 0.27Ohm - quite good.

You should put 1 resisstor of 0.27Ohm, and minimum 2 Watts to every led string to save your led.

of course there are better but not so easy ways to limit leds current, but this is most simply. Remember - connecting led directly to power source is very danger due to dynamic resistance of led - it is "visible" as "short-circuit". Both led and/or power supply can be destroyed in that case.


Thank you for your post and welcome to Manhattan reefs!

I did actually use a current limiter. Its called a buckpuck. I realize that resistors are cheaper but being such a novice at electronics I opted to just pay for the buckpuck instead of using resistors because its simpler.
 

azazel

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I did actually use a current limiter. Its called a buckpuck.

Ups.. it's look like I missed this :( - sorry.

BTW - "buckpuck" is a simple switcher circuit, configured as current limiter.
You can do it DIY with a few elements.

1. Analogue version with many disadvantages like huge heat emission, but really cheap is LM317 + Resistor, connected together to work as current source.


http://users.telenet.be/davshomepage/current-source.htm

2. My favourite way - Macroblock MBI6650 or 6651. a single chip + 4 elements http://download.maritex.com.pl/pdfs/op/MBI6650.pdf

It needs to make simple printed circuit - it can be some disadvantage for beginners, but results are very good. In Poland cost of complete DIY "buckpuck" based on MBI6550 is no more than 2 USD. Based on LM317 - less than 1 USD.

I've made a few different current sources for LEDs, if You are interested I can attach pics and schematics.

Btw - Once again sorry for my english :(
 

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