DIY LEDs - The write-up

[Gomer]

For fans, just use a normal quality PC fan (nominally 12V) and power it with 6-9V. I'm running two Zalman 80mm fans at 6V (old wallwart) and they are dead silent.

 

[der_wille_zur_macht]

If people are using buckpucks or other drivers with 24v supplies, they could put three 12v fans in series to get 8v each. Most fans should be dead quiet at 8v. And this way, it would turn on/off with the LEDs assuming you had the PS plugged into a timer.

 

[widmer]

Thanks for the help guys. Actually, 3 fans would be perfect for me as well since I've got my LEDs divided into three strips...

Can I ask what is the difference between a 3-pin and a 2-pin [computer] case fan? Is it just that one has a grounding line and the other doesn't?

 

[Altpers0na]

2 wire is typically just ground n power, third ware is usually to tell the pc how fast the fan is going.

 

[pbradley0]

Has anyone hooked up buckpucks to an Apex controller for dimming? If so how do you wire this up with multiple buckpucks?

 

[Gomer]

Not a buckpuck, but I am using the APEX to control some Meanwell drivers (they take 0-10VDC).

 

[der_wille_zur_macht]

Apex and other high-end controllers typically have 0-10v analog signals, meant for driving Tunze stream pumps (the Tunze drivers accept a 0-8v analog signal to vary speed) or "traditional" dimmable lighting products (i.e. dimmable fluorescents or dimmable lighting used for stage/show lighting.) In these caess, 10v is typically interpreted as full on, and 0v as full off.

Meanwhile, the buckpucks take a 0-5v DC analog signal, and it's "backwards." 0v is 100% on, and 5v is 100% off. The dimming is actually over a smaller range than this (around 1.5 - 4.5v). It's also notable that the buckpucks provide a 5v reference (up to 20mA) for the dimming circuit. Though you won't need that.

So, there are two challenges for you to overcome:

1) Writing a program in your controller's language that'll provide the correct 0-5v signal. I'm guessing this isn't hard to do, but you want to be sure you're not using the full 0-10v bandwidth the controller can put out.

2) Wiring up the hardware correctly. You will want to apply your 0-5v signal to the CTRL pin, and you'll need to connect the ground from the controller to the buckpuck to complete the circuit. The datasheet shows a bunch of wiring schematics, but none of them exactly match this application. The closest is Figure 15 in the datasheet, which shows a PIC microcontroller, but it shows it powered on the 5v reference from the buckpuck, which you won't be doing. But it DOES show the controller's ground going to the LED- pin. The datasheet mentions grounding controllers to the LED- in the text above these diagrams, too. So, connect the + signal wire from the controller to CTRL, and the - from the controller to LED-. Leave the VREF unconnected.

 

[MikeFisher1972]

ok i did get a little confused and now i am on track.
i am going to do 36 Leds on one 2' by 2' section.
i will use 3 mean well ELN-60-48 drivers.
i wanted to do something like 24 white and 12 blue, that way i can run them all seperate on each driver.
the heat sink will be purchesed by www.heatsinkusa.com
is there any sugestions where to get the drivers and led from?????
thank you.

 

[SW_nOOb_SC]

http://www.nanotuners.com/index.php?cPath=74 has some of the best prices i've found.

 

[widmer]

While we're talking about dimming and buckpucks, I just got four of the wired buck pucks with pot from LEDSupply, which I was going to hook up to a 24v supply. I guess I didn't look closely when I ordered, and have found that there's no separate input for 0-5V for pot dimming. Does this mean it's simply all set to go with the pot, when I plug it into the 24v supply? That's my guess, but it would be good to be sure...

 

[der_wille_zur_macht]

ok i did get a little confused and now i am on track.
i am going to do 36 Leds on one 2' by 2' section.
i will use 3 mean well ELN-60-48 drivers.
i wanted to do something like 24 white and 12 blue, that way i can run them all seperate on each driver.
the heat sink will be purchesed by www.heatsinkusa.com
is there any sugestions where to get the drivers and led from?????
thank you.

http://www.nanotuners.com/index.php?cPath=74 has some of the best prices i've found.

Nanotuners has good pricing in small volumes, but in larger volumes, it makes sense to shop a bit. dealextreme.com has an AWESOME price on the cool whites, but they are overseas so shipping is slow. ETG tech usually has good pricing, but you have to call (no online ordering.)

While we're talking about dimming and buckpucks, I just got four of the wired buck pucks with pot from LEDSupply, which I was going to hook up to a 24v supply. I guess I didn't look closely when I ordered, and have found that there's no separate input for 0-5V for pot dimming. Does this mean it's simply all set to go with the pot, when I plug it into the 24v supply? That's my guess, but it would be good to be sure...

The pot is powered from the vref pin on the driver. That pin supplies +5V (up to 20mA) and is intended to power dimming solutions. So yes, the buckpuck is a plug and play package when you buy it with the pot, just hook it up to your 24v supply and turn the knob to adjust.

 

[widmer]

Also, I finally made up my mind and ordered two heatsinks from www.heatsinkusa.com of their JUMBO material :spin1:.

Yes, the fins on that stuff are 2.5" tall LOL!

Haven't seen anyone on here using it yet. And it's not that I'm hardcore about heatsinking, but it actually ended up being my cheapest option, since I needed two strips that were 10 x 1 inch. I'm going to line up 9 Cree XRE stars on each one with only 1/8" space in between each star. I wonder if I'll need a fan now?

 

[der_wille_zur_macht]

I wonder if I'll need a fan now?

I would say definitely yes. My nano units are 8 LEDs on a big PC CPU heatsink (probably similar surface area to the sinks you're using) and at even 500mA drive current, the sink gets really hot without a fan.

 

[widmer]

Good to know. I'll go ahead and do an ebay order on that then too. Also, thx for confirming the buck puck pot situation.

 

[hostage-46]

So as much as I love the idea of LED's it looks like getting them to work with a controller will we a challenge yes?

 

[der_wille_zur_macht]

If you can solder up an LED array, getting it to work with a controller is a walk in the park. It's really just a matter of making sure you get compatible stuff (i.e. don't try to use a controller that generates a 0-10v analog signal with a driver that needs a PWM signal.

Though, even in those cases, it's probably just a simple external circuit that'll get things working.

 

[SW_nOOb_SC]

So I wanted to get the pros opinions here...I'm looking to setup an LED setup soon and here is what i'm thinking for a 20x20x16 almost cube tank. Please excuse my lack of electrical knowledge in advance.

32 LEDs, 16 Cree XRe whites, 16 Cree XRe RBs.
8.5"x16" Heatsink
2-3 120mm PC fans

Having this many LEDs would mean I'd have to use 6 Buckpuck correct? I would like to use Buckpucks because of their ease of use and ability to just hook up a pot and go. My question is, using this many Buckpucks, what size power supply will I need to be looking for to run this setup?

Is it possible to run the buckpucks together, as in a single cord out of the fixture to the power supply? (Obiv you have a ground and a power wire so 2 technically).

Is it possible to wire all of my white buckpuck drivers together and all my blues together so I can run just 2 Pots? Or would this not be as feasible since they come with pots already? I've heard i'd should maybe replace the pots with 5k pots from radio shack?

Is it the whole heatsink that gets hot or just inside the fins? I wanted to know how hot this fixture would be so I could find a good way to mount it.

 

[james3370]

So I wanted to get the pros opinions here...I'm looking to setup an LED setup soon and here is what i'm thinking for a 20x20x16 almost cube tank. Please excuse my lack of electrical knowledge in advance.

32 LEDs, 16 Cree XRe whites, 16 Cree XRe RBs.
8.5"x16" Heatsink
2-3 120mm PC fans

Having this many LEDs would mean I'd have to use 6 Buckpuck correct? I would like to use Buckpucks because of their ease of use and ability to just hook up a pot and go. My question is, using this many Buckpucks, what size power supply will I need to be looking for to run this setup?

each buckpuck can run up to 6 LEDs, so personally, i'd run 30 LEDs to keep it simple (5 buckpucks). what i had thought about doing on the tank i was planning was seperating the whites & blues (as you mention below) on 2 buckpucks for each white set of 6 & each blue set of 6 & doing a single buckpuck of 3 white & 3 blue (save a few bucks & make it non-dimmable) & put it on a seperate power supply. then you could time them seperately for a nice sunrise/sunset....all blues come on>>>>white/blue comes on also>>>>all whites come on also>>>reverse for sunset

if seperating the whites & blues (as you mention below), & running each string at 700ma, you would need a 24v power supply that put out at least 1.5amps....like THIS one (so 2 of those) & then you'd need a 3rd one of those that would run the 50/50 string of white/blues & you could also run the fans for the heatsink on it as well.

if however, you want them to be an "all on/all off" w/out the sunrise/sunset effect, you'd need 24v & about 4amps for all the LEDs & the heatsink fans....THIS one would fit the bill

it really comes down to how much the sunrise/sunset is worth to ya as far as the extra cost of seperate power supplies

Is it possible to run the buckpucks together, as in a single cord out of the fixture to the power supply? (Obiv you have a ground and a power wire so 2 technically).

you would need a multi-conductor wire cause you need (2) wires for each string of 6 LEDs back to it's respective buckpuck....positive input into the string & neg return back to the power supply

so if you were doing 5 buckpucks, that's 10 wires plus 2 more wires for the heatsink fans.....for a total of 12 conductors. i think home depot/lowes sells 4-conductor wire, so 3 of them would work fine

Is it possible to wire all of my white buckpuck drivers together and all my blues together so I can run just 2 Pots? Or would this not be as feasible since they come with pots already? I've heard i'd should maybe replace the pots with 5k pots from radio shack?

my experience w/ the buckpucks that come pre-wired w/ pots for the dimming is they are very easy to break & then have to be replaced w/ something from radio shack, so save a few bucks & order the ones that don't have the pot...just bare wires.

if you decide to do as i stated above & do 2 buckpucks of whites & 2 or blues, then you just need a gang-pot like THIS....one for the whites & one for the blues

a "gang pot" has multiple inputs & outputs depending on how many "gangs" it has. that one is a dual-gang, so it will control 2 inputs/outputs w/ just one knob, so if you had 1 for the whites, it would dim both buckpucks at once....same for the blues

Is it the whole heatsink that gets hot or just inside the fins? I wanted to know how hot this fixture would be so I could find a good way to mount it.

the whole thing is basically a radiator, so it all gets hot & the heat radiates out the fins. most however are finding that these heatsinks are pretty much overkill unless you are filling it w/ LEDs & running them at high current....so you should be fine w/ only 1 or 2 decent-sized pc fan(s) & it'd be barely warm to the touch

 

[Gomer]

most however are finding that these heatsinks are pretty much overkill unless you are filling it w/ LEDs & running them at high current....so you should be fine w/ only 1 or 2 decent-sized pc fan(s) & it'd be barely wam to the touch

Have a ~7.5 x 14" heatsink with 36 LEDs at 1amp each and 2 80mm computer fans run at 6v. heatsink barely gets warm.

 

[SW_nOOb_SC]

Thanks for the replies. I'll brainstorm it a bit more and see what I can work up.