real cheap led moon lights

[55chadman]

look in the auto sections of some discount stores and look for the led washer nozzels some time they will go for real cheap ---- ive seen them at some places for 3.00 for a pair you will have to take apart the housing but it has a resistor already on it and its set up for 12v also look for cig lighter things that plug into them that light up i say a black widow light up knob that lit up --- just pop it apart and there you go it was a bigger led and had a resistor too i think i say it for .99 the past few days

these places are like freds and big lots and even k-mart

hth

chad

[grim]

The moon isn't red.. :)

jb

[Glass World]

Originally posted by grim
The moon isn't red.. :)

jb

I've seen the things he's talking about and I think they come in blue and white too. I'm not sure if they would really be cost effective or not... I can imagine you should be able to find two LEDs and resistors for under $2.99.

[grim]

Nevermind, that's what I get for trying to read reefcentral while on a conference call in work, I thought I saw 'red' in there somewhere.. :)

jb

[55chadman]

ya you can get them in just about any color but most of them i have seen have been blue and white it may be cheaper some where elese but for sombody who asks all the time of which resistors to buy well here you go no need to look around at rat shaq it shouldn't matter what p/s you hook up to them (as long as its 12v dc)

hth

chad

[bshumake]

i have a site i got 5 150ohm resistors for .25 cents and 5 470nm LED's for 2.25. whole thing including shipping was only $4.50. i'll post it when i get home.

[bshumake]

http://www.lsdiodes.com/
here you go

[Quicksilver]

There was a guy in the selling forum selling blue LEDS with resistors for .40 each. I picked up a few and wired them up. They work great. Just used a 9V converter laying around from a old answering machine. Once I soldered the connections close to the LED I hot glued them. This way I could maneuver and aim them without worring about the wires touching. HTH WILLIAM

[kansas1051]

i bought 50 470nm 3.3V blue LEDS for $8 of ebay including shipping. I bought 150 resistors for $3 including shipping which match the LEDs to a 6V power supply.

[bshumake]

WOW! I must have been looking in the wrong section. i didn't find any LED's when i looked.

[Entropy]

Actually the car washer led setup would probably work great. Just get the blue ones and hook them to a really small 12v transformer. It may cost you $10-15 for everything but what a simple setup already wired and ready to go. Not everyone has a soldering iron afterall :D

[Spoonsil]

Does anyone have pictures of what they have put together so far? This sounds a lot easier and cheaper than purchasing them assembled.

Lorie

[Quicksilver]

Lorie, This was the wiring diagram I found when wiring mine. HTH William

http://www.kaotica.com/frag/diy/moonlight/

[vapovick]

just built one, looks great ,, heres the link

http://www.lc-led.com/View.jsp?idProduct=64

[sfsuphysics]

Yikes that's pricy!

Try Ebay, I just picked up 50 4000mcd blues for 24 cents apiece, plan on ordering some UV & whites from his store as well.

[sfsuphysics]

Ok my bag of 50 4000mcd 470nm blues came the other day and after testing them all, found out they were all extremely close in voltage (for a given resistance). So trying to do cool things with them in parallel, I found out it would be easier just to pull out the old breadboard and plug them in there.. took a few pictures so here they are. Oh and to keep with the topic, the setup is about 24 cents each for the LEDs, 1.5 cents for the resistor, and the ac-dc converter was scavanged from an old pair of computer speakers that long since went in the garbage. So ignoring minor cost of things like wire & solder, about $6.50 (for those 21 leds)

Here's the array set up, btw a single resistor of 20 ohms for the whole thing (and no that is not too small). Notice nemo for touch ;)

http://www.physics.sfsu.edu/~mbolling/ready.jpg

Now this is a pitch black room, and my crappy camera does not have the flash on or any "low light" smart technology. Also note that the light being cast off to illuminate everything and cast shadows is from the side of the led (ie out of its main viewing angle rating).

http://www.physics.sfsu.edu/~mbolling/21ledsalute.jpg

The final image, a picture of the ceiling about 7 feet away from the LEDs. Btw the blob you see is about 5 feet wide. The picture really does no justice to how bright it is.
http://www.physics.sfsu.edu/~mbolling/theblob.jpg

[Saltybob]

I bought 100 led and 100 resistors for $15.50 shipped went to HD and bought a plastic 8'x3/4" L trim corner spaced holes 16" ran the wires to the inside LEDs pointed out. Hotglued the conections to prevent rust. I made a 2nd one for a friend but I did not like the spot like efect so I ground the tips of the LEDs flat and polished them with a buffer. I used 2 wire 18 gauge for door bells from HD and just stripped enough to soldier the LEDs to. Mounted with SS screws so all you see is a white 3/4" strip. Old
cell phone chargers work well for a power source

[Trackz]

Originally posted by Saltybob
Old cell phone chargers work well for a power source

Especially check out Nokia chargers. For a parallel setup, they are rated at 3.5v out of the box. The current is enough for about 10-12 leds. Make sure to check it with a meter though first. I didn't and burned a LED up. (must only be 3.5v under load.

[Saltybob]

Actually I used the older nokia charger at 6vdc with resistors to match I have 5 running off the 1 power supply.
I'm no electrician but my friend said that this is good and so far it is

[vapovick]

Originally posted by Saltybob
I bought 100 led and 100 resistors for $15.50 shipped



where did you get them ? do you have a link ?

[Saltybob]

Here you go250 blue 5mm LEDs $33.00 (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26207&item=2596313472)
100 10mm LEDs for $31.00 they did not have these last month I wish they did (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26207&item=2595508168)
I would use the 10mm next time

[Saltybob]

They will change out the resistor if you ask.

[Saltybob]

http://reefcentral.com/gallery/showphoto.php?photo=26741&papass=&sort=1&thecat=500
http://reefcentral.com/gallery/showphoto.php?photo=26740&papass=&sort=1&thecat=500

Came out pretty clean other then I thought I was using a dry erase marker

[sfsuphysics]

got a paypal account? www.besthongkong.com and as of now they have free shipping, since most dont need 100 blue leds (unless you have a monster tank) you can get 50 for $9, 10 cost $7, so might as well put in a couple bucks more and get 4x as many :)

I wouldn't bother with the 'add on' resistors they're 470 ohm which are rated for 12V batteries (since cars are the big seller for these). Go to someplace like Fry's (not radio shack!) and you can get a pack of 100 for $1.50.

[bzzbee2]

yea frys is cheaper, but there arent a lot of frys. radioshack lets you buy like 5 or 6 for .99. which isnt really that bad. are you really going to wire up 100 led's in your tank.. also, the required resistor size for the 12v source will vary with the LED. some are rated at diff voltages than others, requireing different resistance for proper lighting. do the calculation to be sure.

http://www.ledsupply.com/techinfo.html

here is a link to a resistance calculator which will allow you to get the best lighting out of your LED, by providing it with the correct amount of juice. all the figures it asks for will be or should be included with the led's that you buy. if you dont know or they dont show them.. dont buy them. then just enter in your source voltage and BAMM you have the correct resistance needed to properly power your LED.

[sfsuphysics]

Well even if you buy from a company with a particular 'stat sheet' chances are the voltage requirements can be different for each LED within the bunch. Sometimes its "easier" just to grab a multimeter and a variable resistor helps (I use a decade box) and just hook up to read current, and test each one individually. Then sort out those that run radically different and hook those up with individual resistors if need be. I just went through a batch of 50 blues this way, and found that all of them ran with the same current within a few microAmps, so luckily 1 resistor will do ok.

True with radio shack though, if you only need a few resistors 99 cents isn't bad and its close. But if you need more, driving an additional hour to get them might be worth it (even with the cost of gas!). Luckily a Fry's is 40 minutes from me in Palo Alto, so saves my checkbook from "browsing" too often :)

[55chadman]

so if i got the 100 pack of led lights from one of the vendors listed on this thread and wanted to hook up all 100 of them and use one power supply i only have to use one resistor also do i hook them in series or parallel i think i might have to try this i have a few extra bucks on hand and i think i want to try (goof off on a 7 gallon tank) i have a few hermits and rock

i was thinking 200 blue and 100 white pick up one of those diy pcb boards with ecther and pen at rad-shaq draw out-drill-ech and solder then put some coating on it so it wont rust

any thoughts

chad

[bzzbee2]

NO! To wire LED's Correctly you should have 1 resistor per LED. and all should be wired to the main wire. Like shown in the link on the previous page.
http://www.kaotica.com/frag/diy/moonlight/
there it is again.. look at that all blue diagram.

as far as using the white led's i think it would be cool to see if they threw enough light to auctually light a tank to the point that the inhabitants were happy! so what if your running 400 super bright white LED's at like 12000mcd. not only would it be cool in temp, but you wouldnt have to replace them as often. just imagine a board about 24" long and 6" wide with nothing but super bright LED's... humm i just might do something like this as a cure for boredom... let me know how yours turns out. it think it would work great for a 7gal tank...

[bshumake]

bzzbee2
dude...that 24 x 6 would be an impressive thing to see. yeah it might be expensive on the front end, but could you imagine the amount of money you would save on replacement bulbs, ballasts, etc. OMG. that would be something to see.

[bzzbee2]

Expensive... im willing to bet it would cost less than 100 to do the whole thing. and you could have a couple different circuits on it one with white lights, and the other with like 5 blues for night lighting...

bla what am i thinking... we're using all the same type of led's... its when you mix and match that you need to use different resistors as the different led's draw different amts of juice... just use ohms law and you can figure the type of resistor you need for several leds together..

[55chadman]

i didnt thin you could get away with only one resistor -must have had a brain fart !!!!

im gonna have to do it ill get all the stuff in the next few weeks and start this progect ill take pics

chad

[sfsuphysics]

Well you CAN get away with one resistor. Some people on websites say "current takes the path of least resistance" well this is complete B.S. well ok its partially B.S. a majority of the current will take the path of least resistance. But if you have a bunch of LEDs (say 25-50) that are all pretty closely matched the only thing that'll happen is those that have little less resistance will draw a minimal amount of extra charge, to combat this you could put a little more resistance on that initial resistor and it'll lessen the current for the other resistors, it will hardly be a noticable change. Its when you have LEDs with a noticable difference in resistance (ie how many volts they need) that you get into problems, as mentioned, and if you dont want to go with individual resistors you can either pump more current into one LED (making it brighter and burning out quicker) or lessen the current to the other LED making it dimmer.

If you ask me though I'd just keep all similar LEDs on the same parallel connection, then just put approriate resistors on those, and hook those up to the main power source seperately, either in series or in parallel of each other. Nothing a little ohm's law can't help you solve :)

[bzzbee2]

Sfs is right. i wasnt thinking. in the past my work with LED's involved 3-4 different LED's in which case each has different req for power. in which case you would want different resistors for the LED's i.e. 1 red led, 1 blue led, and 1 green LED.

[bzzbee2]

SFS, what kidna multimeter are you using to test your LED's. i am looking into picking up another one sometime soon.. if i remember correctly i need one that can test diodes correct? its all coming back to me, but slowly......

[sfsuphysics]

ummm generic radioshack type multimeter. No real brand specificion is necessary.

Testing diodes? umm sure, although doubt it'll do much for LEDs. My diode test feature doesn't work with LEDs, but unsure if it should (or maybe a fuse is blown).

[bzzbee2]

ok. one more question.. when your running say 20 led's off one resistor. the led's are 3.6v current across them.. when figuring with ohms law... if i have 3 of these led's it running from say a 12v source. it would be 12 - 3.6 - 3.6 - 3.6 = 1.2v 1.2/.02 = 60.. so i would need a 62 ohm resistor correct... so what kinda power source are ya using... or am i missing something... im a visual learner.. if you could do a diagram that would be super!

thanks for any help

[robwsup]

I just bought these:

Blue Ebay LED's (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2598114668&category=26207&sspagename=STRK%3AMEBWN%3AIT&rd=1)

What value resistor do I need with a 6v or 12v power source? Is there a formula to determine the resistance?

Robert

[robwsup]

Also, I'm going to put these over my 150 (see my avatar) It's 48"Lx24"Wx30"H. How many of these LED's do you recommend?

[bzzbee2]

you can get m 5x more for just a few more dollars...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2598556506&category=26207

also look at my post on the previous page. it has a link to a resistance calculator which will tell you what you need. ohm's law is basically what your using to find resistance needed...

[robwsup]

You are correct, but I don't Ebay with people overseas.

[MartyDW]

be carefull with running one resistor for the whole bunch, make sure the resistor is able to handle the wattage and current and also the power supply will have the amps to push the amount of LED's you plan on using.

[BeanAnimal]

Running LEDs in SERIES is more efficient. Please be aware that the swing voltage of your power supply will have a greater effect on the led brghtness. In other words if you only hav 0.3 volts left over, that gives you very little room for power supply voltage fluction before the LEDs go out.


Bill

I edited this post...Series is more efficient....not parallel!

[robwsup]

The LED's I purchased run at 3.5v. I'm planning on running them on a 6v power supply, in parallel of course.

[robwsup]

bzzbee2
I didn't think to use Ohm's law to figure the resistance. I thought that LED's provided at least some resistance in the circuit.

[sfsuphysics]

Ok I need to retract my statement about 1 resistor being ok, while yes it is true it MIGHT be ok, you also have to check the power rating of the resistor, I hooked up 25 whites in parallel and checked out what resistor I'd need ( http://www.projectx.com/Kits/LEDNotes/ ), 18 ohm resistor no problem, hook it up.. oooh smoke *DISCONNECT* Seems I was putting about 5 watts of power through a resistor rated at .25 watts *bashful grin* Anyways, after some series & parallel combinations of resistors I got 22 ohms with enough resistors to discipate the power within safety specs.

And while it was a really bright light (it outshone the NO bulb i had over my tank that's brewin') it was over a relatively small area. It might be great for nano's, but then again how much would it cost to light a nano? As it stands I can build 220W of 10000k PCs for less than $80 (not including oak hood), doubt LEDs will be that effective.

As to the ebay thing, be careful, always check the shipping, that canadian firm while yes $6.33 for 50, also has $8 shipping :)

For those who want to experiment around and dont want to buy 50 LEDs (remember many have done moonlights with 5 or less depending on tank size) I'll sell you some for like 50 cents a piece plus 37 for a stamp :) I have 470nm blues (4000mcd), 420nm UV, and 10000mcd whites.

[BeanAnimal]

Hrmm you can send a handful this way :P

[bshumake]

So. If i'm gonna make a harness of 6 LED's powered by a 6 volt power supply would i use one 1K ohm resistor?

[sfsuphysics]

Well powered by a 6volt supply, according to http://www.projectx.com/Kits/LEDNotes/ You'd need 27 ohms only, NOT 1k! And unless your resistors are rated atleast .5 watts you'd want to double up with 2 resistors (either 2 in series add resistance, so 2x 14ohms, or in parallel halve the number if its the same resistance so 54ohms each in parallel).

You need to do the LEDs parallel btw, because 6Volts will barely light up 2 in series. Conversely you can add a resistor to each LED in parallel which 150ohms would do (is that where you got the 1k number??)

BeanAnimal, were you being sarcastic? If not send me a PM(anyone else too) and we can arrange how ever many you need, I only have 50 blues (100 each of the UV & Whites), but if you need that many I can get more.

[bshumake]

Originally posted by sfsuphysics
Conversely you can add a resistor to each LED in parallel which 150ohms would do (is that where you got the 1k number??)

yeah. thats where i got the 1K. Thanks. I'm thinking of building a couple more for some friends and i'm not having much luck getting all 5 LED's to work. I can get 4 out of 5 going. I'm not sure if the resistors are bad or if the LED is. I'm using the kaotica.com plans btw. Mine came out really nice.

[sfsuphysics]

If you put a single 1k resistor in parallel that is probably why your LED didn't work (test it out by putting it by itself), simply put there's too big of a load that's dropping the current down to a point that the highest load (even a minute difference) will be so "big" that it doesn't get enough current, I ran into that problem earlier with my whites, and didn't understand it until I drew a diagram and traced out pathways.

[Saltybob]

I built my second set but I ground the tips of the LEDs down flat with a grinder then polished them with ruge and puffer to get rid of the spot light efect. Allways nice to have a few extras layin around to experiment with. Work better then I hoped and its nice even spred.

[bzzbee2]

that was the place that i bought some of my LED's from. they were fast shippers, and they even threw in a keychain light. If you do the math by buying the pack of 50 your roughly paying half price per LED that you would by buying the ten pack. Im not saying that it wont work for ya. but i know i tend to screw things up ocassionally. and if you try to use say 6 in one setup and something goes a bit haywire.. now you have to buy more to get your six light setup. i also bought some from another place on ebay... got 25 for like 8 dollars with 2 dollars shipping.

one more thing. if you are using different color led's like white and blue. you should put them on a different circut, as they require different amts of voltage. running them in series may cause dammage if they are not the same type.

sfs, thats an awesome link for calculating resistance. thank you for that great resource! Time for me to beef up my resistance.. im only running 1/2w resistors on my setup and that calculation tool calls for at least 1.35w resistors... well, off to frys..

[69vette]

Originally posted by sfsuphysics
I only have 50 blues (100 each of the UV & Whites)

sfsuphysics,

Are you using the UV LED's on your tank? If so, what do they look like?

[sfsuphysics]

bzzbee: Dont worry about gettin resistors that'll hand 1.35 watts each, that's just the power discipated by a single resistor if that's all you used. If you do some series or parallel combinations of 1/2 watt resistors to get the equivilant resistance you'll have a total capacity of 1.5 watts, it just looks more messy because you have 3 resistors instead of 1. But the resistors that discipate more power are usually noticiably fatter.

69vette I have yet to put UV's over the tank, just because I've not really thought about doing it on my current active tank, figured I'd throw it on the big one that's being built.. but I could easily slide some UV's next to the blues and run those to get an idea of look. Although because of 420nm it doesn't look very bright, it looks at most like a pale purple (and for obviously reason I'd rather not stare at them too long *Grin*).

I did do a little mockup on a breadboard of a combinations of whites, blues & UVs all at once and seems to give a very nice color distribution (although you could hardly tell from the pictures). I posted it on one of the other many LED threads floating around.. might as well post some here.

[69vette]

What do you think the UV would be like for moonlights?

[Chromatic]

What do you think the UV would be like for moonlights?

I don't agree with using 420nm LEDs for moonlights, although they look real nice (coral fluorescence), you shouldn't "over do it."

If you look up "black light" here on the forums, you will see that UV can damage your fish (depending on the fish type).

http://www.vthrc.uq.edu.au:16080/ecovis/StaffPostgrads/images/Visual%20Biology%20of%20Hawaiian%20Reef%20Fish%20I.pdf

The question would be how much UV light would be reflected off of the moon and settle down through the water into the reef at night???

I don't think very much.

[sfsuphysics]

Hmmm I could of swore I replied to that 420nm question.. maybe the board crashed that day..
But yah I agree with Chromatic 420nm moonlights is not good, 470 is because it mimics what the moon really is, 420nm is what actinic lights peak at and you wouldn't keep them on all night either, but only for sun rise/set settings, and thoughout the day.

Chromo: btw blacklights operate in the UV-A region, 310-400nm, 420nm while isn't UV, it is very violet (borderline UV) but still safe for fish, infact from what I understand encourages growth in photosensitive creatures.