LED pool lighting project - Page 1
Forum section: electronics / general

author: Joshua
author_rank: Regular Contributor
timestamp: March 22, 2012, 03:36:58 am
content: Hey guys, been a while...Even though it is only March here (KY, USA), it was in the upper eighties lower nineties today. It's gettin about time to open the swimming pool. There's a project I've been wanting to undertake quite some time and that is rgb led lighting for the pool.Basically, here is my goal....Now there are various aspects to this design that I am looking for some ideas on.I plan on probably having about 8 or so rgb leds around the pool. That will be determined after experimentation with how effecient they light the water.----Power----I am thinking that each individual led will have it's own smps near it. The pool is 21' x 41' and so I don't know if sending thick wire all the way around will be very cost effective, seeing as I could use smaller conductors for higher voltage AC.----Control----I will have one major control board which will handle coordination of all leds. I also think that if I am having individual PSUs at each led I will have to have a small driver board as well. I would also be able to have a trim pot(?) at each led in order to calibrate it to the others. Not sure if that will be necessary or not. Probably not. I also plan to eventually (who knows when that could be) experiment with laminar streams that will also be rgb lit. All of the system will be controlled with one main board. I also would like to eventually be able to program light shows that are synced with music or whatever. Any thoughts on the general architecture of the control system? Any micros especially suited for the main board?---Heat----Okay, this is the fun part. These leds are going to get HOT. I was thinking, why not submerge the leds directly in the water. The water is always circulating and this would create the optimum light transfer, as well as great heat sinking. Can leds be submerged, or would they have to be behind a barrier. I also thought the leds could be covered with a large piece of clear heat shrink sealed at the ends with silicone. If directly submerged, would the aluminum(I assume it is aluminum) be quicky corroded by the chlorinated water? What about having the leds outside the water and transferring the light via a fiber optic cable, although this loses any built in heat dissipation effects. I have quite a few ideas on this part of the design, but every one has its ups and downs. Any thoughts?This project has many facets to it and it seems like I am not exactly sure where to start. Maybe I can find some submersible rgb leds, although I wasn't able to find any that looked like a perfect fit. Any suggestions? Once I figure out how to actually get the light into the pool, I can have fun designing the power supplies and the control circuits.Thanks for any ideas, input, stories to tell etc....Joshua

author: IanB
author_rank: Super Contributor
timestamp: March 22, 2012, 05:10:15 am
content: I think I would keep all the high voltage stuff and the controls in a weather proof cabinet far away from the poolside, out of harm's way. Running low voltage wiring around the pool is not going to be that inefficient with a current of, say, 700 mA per emitter. The constant current driver will compensate for the wiring resistance in any case so the brightness won't suffer.I definitely don't think you can submerge bare LEDs or associated wiring. They will corrode and fail in no time.I've always seen underwater lighting done as a fixed installation having glass windows in the pool wall and a dry enclosure behind. I don't know how you would do an ad-hoc lighting scheme. Perhaps you could construct a sealed aluminum enclosure with a plastic window in the front and use the metal of the enclosure as a heat sink? Submerging the enclosure would then give you plenty of cooling. You then would just need a dry way to get the cable to the enclosure--a rigid sealed conduit, or a water-tight cable entry grommet?

author: Dago
author_rank: Frequent Contributor
timestamp: March 22, 2012, 08:24:16 am
content: You absolutely cannot submerge the leds in the water. That does not mean the leds cannot be cooled by water. I'm having trouble visualizing how you are going to mount the leds? Like are there premade holes in the side of the pool for lights or are you trying to do this without having/making holes to the pool itself?

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: March 22, 2012, 09:35:14 am
content: As far as waterproofing at low pressure goes, its actually quite easy with a bit of practice. I worked in the Aquaculture industry for a few years and not surprisingly the subject came up quite often.The successful methods I have seen tend to rely on either:a greased rubber o-ring between two flat surfaces with tightening bolts placed outside the seal.Or using potting compound to make the seal.You normally want to minimise the amount of air in the cavity so it is not too buoyant.You can work wonders with PVC pipe and endcaps too.Silicon for roof guttering can be ok, but it can develop leaks over time so we tended not to use it.For testing sometimes I used to pump air into the device and see if bubbles come out, that way the internals stayed dry as the air was flowing out rather than the water in.In my job my least favourite device actually had 17 potential points of ingress, so testing was mandatory.One really nice camera we used had 360 degree rotation and was sealed by a sliding oring, it was ok to about 30m.Your project sounds like fun.Definitely you have to go low voltage for safety and leds are dc anyway. So say 24 -48 v dc.Cable losses wont worry you at 1 or so amps. Just use the tinned marine power cable they use for boats, its 4-6mm in Aus. Quite cheap too.

author: PetrosA
author_rank: Frequent Contributor
timestamp: March 23, 2012, 12:33:28 am
content: Your flag says you live in the US. If that's the case, you don't want to put any lighting or lighting assembly within 10 feet of the pool that's not UL listed for it. If anything would happen to anyone (think your neighbor's kid, dog etc.), your ass will be in a heap of trouble. Pool lighting is one of the strictest sections of the NEC and not one you want to mess with.

author: slateraptor
author_rank: Frequent Contributor
timestamp: March 23, 2012, 01:37:04 am
content: Quote from: Joshua on March 22, 2012, 03:36:58 amYou mean it's not March everywhere else around the world?On a serious note, I second PetrosA's comment.

author: Joshua
author_rank: Regular Contributor
timestamp: March 23, 2012, 03:27:24 am
content: Quote from: IanB on March 22, 2012, 05:10:15 amMaybe if I had some sort of smooth(can't tear the liner!) aluminum(?) enclosure like you say, I could find one with a window. For all you chemists, will the aluminum be a problem in the chlorinated water. I assume stainless should be okay, but I'm not sure exactly how aluminum reacts with chlorine.Quote from: Dago on March 22, 2012, 08:24:16 amYes, it is an above-ground pool with a vinyl liner. I have to do this without making holes in the side of the wall and liner. Everything has to come from over the side.Quote from: HackedFridgeMagnet on March 22, 2012, 09:35:14 amWhat about like a clear acrylic pipe? I could get an aluminum pipe and endcap, cut it about 1/2 an inch long and mount the led in that. Then cover the end with some sort of clear acrylic...Quote from: PetrosA on March 23, 2012, 12:33:28 amWay to ruin the fun!Nah just kidding, I didn't even think about that. Hmmmmmm what to do, what to do.... I live in a pretty secluded area, and the pool will be fenced. Do you know if I have to merely comply with NEC, or actually have something that is UL listed. Doesn't the UL listing mean that it is certified (by a third party) to comply with the NEC? For instance, if I was able to make everything comply with the NEC, would I be okay?Quote from: slateraptor on March 23, 2012, 01:37:04 amHahaha, well I of course wrote that post intending to release it on the 31st, where it is already April in other parts of the world.

author: Unknown
author_rank: Unknown
timestamp: March 23, 2012, 04:03:03 am
content: The best examples I have seen used fibre optics to/throughout the pool area and a light box concentrator for the halogen and LED light sources. A pool area is a hideous environment for anything electrical/electronic, the fibre though initially expensive is set and forget.No moisture worries, no electrical safety concerns and no weekly repairs of poolside lamps.http://www.opticfibrelighting.com.au/Pool.html

author: johnwa
author_rank: Frequent Contributor
timestamp: March 23, 2012, 09:31:26 am
content: You might want to look at Clive's RGB controller:http://www.bigclive.com/rgblite.htm. I have used these for a few projects, they work well.Quote from: HackedFridgeMagnet link=topic=7519.msg99272#msg99272I agree, I have had some bad experiences using silicone for waterproofing. I think you really need something that will 'flow', and fill all the voids. I think you can get some two part silicones with this property, but conventional roof & gutter silicone in a tube is not much good.Quote from: PetrosA on March 23, 2012, 12:33:28 amI think in situations like this, it is best to just make sure the thing is intrinsically safe in the first place, then you won't have to worry about any possible consequences. Given the low power consumption of LEDs, rechargeable batteries might be an option.

author: PetrosA
author_rank: Frequent Contributor
timestamp: March 23, 2012, 12:03:00 pm
content: Quote from: johnwa on March 23, 2012, 09:31:26 amI think batteries would be a safe way to go. Especially 12V or lessAnything hooked up to the mains near a pool that isn't UL listed is a potential liability. It's not a question of conforming to the NEC (the code only governs the installation). UL (and other similar agencies) perform safety testing of the electrical gear itself for its intended usage. A particular product, installed in a particular method for a particular use can then be called "safe" based on it's UL listing. To complete the formalities, it's often required to be installed by a qualified professional and inspected, otherwise you give insurance companies an excuse to refuse paying out claims or a judge the ability to assign liability to someone other than the manufacturer. UL stands for Underwriters' Laboratories and electrical inspectors are technically known as underwriter agents (or something similar) which means that they offer certification to insurance companies that confirm the insurability of either the gear or installations. Electrical inspectors are also responsible for checking that the gear is all listed by UL or other approved agency. If it's not, the inspectors can potentially declare it safe themselves, but usually won't take that liability on themselves.

author: Psi
author_rank: Super Contributor
timestamp: March 23, 2012, 12:31:13 pm
content: If you had a small solar panel top keep the batteries charged that could work.The majority of the time you wouldn't be using the pool and it would have plenty of time to charge.

author: FulThrotl
author_rank: Newbie
timestamp: March 23, 2012, 10:47:04 pm
content: Quote from: Joshua on March 23, 2012, 03:27:24 amok, i actually went and subscribed here, just for you.after i read your post, i was speechless.allow me to share some things with you.i am a licensed electrical contractor in calif.i've been doing this for 33 years.ok, firstly, there are fiber optic coping lights that go under the edge of the coping that have NO ELECTRICAL IN THE POOL WATER AT ALL.pool chemicals don't affect them. they work great.http://www.inyopools.com/Products/01900015000625.htm?gclid=CLiT58qG_q4CFQ0FRQodOnYX1Athey use a remote light source that can change color and do a number of things, including dance to music.as for pool lights, you can get LED ones that run on 12 volt, so there IS NO LETHAL ELECTRICAL POTENTIAL IN THE WATER AT ALL.they are expensive, but they draw 5% of the power of a regular lamp.two wet niche pool lights consume MORE ELECTRICITY THAN YOUR POOL PUMP MOTOR.now, i can't state the following strongly enough:POOL ELECTRICAL WIRING, AND ANY WIRING WITHIN TEN FEET OF A POOL IS ***NOT*** A TASKFOR SOMEONE WITHOUT FORMAL KNOWLEDGE OF THE NATIONAL ELECTRICAL CODE.you have no idea how easy it is to kill someone. all it takes is 50 milliamps of current flow thru thebody, and that can induce a heart attack. THAT CAN BE DONE WITH AS LITTLE AS 30 VOLTS.i had a customer a few years ago, a fairly affluent businessman who had a number of rentalproperties. one of them had a pool. he called me out to fix the pool pump which wouldn't work.when i saw how it was wired, i wouldn't touch it. it was obvious that the tenant of the house hadperformed some "loving hands of home" renovations on the house and pool wiring.all the owner of the house could talk about was that his property was upside down on cash flow.i walked out of there without doing any work, or accepting any money.the owner set out to fix it himself.a year later, i got a phone call from the homicide division of the local police department, wantingto know what i knew about pool wiring at a house. nine months later, a girl swimming in thepool was electrocuted, and died.the property owner had given the police my business card, told them i was his electrician, andi'd checked the wiring and said everything was ok.i testified before the grand jury three separate times on this matter. they ended up indictingthe property owner, who was convicted of MANSLAUGHTER, and went to prison for severalyears, at the age of 62.he lost two apartment buildings, and eight houses, i believe.everyone involved in any way with this got sued for US $2.5 million.the property owner, the tenants, the pool cleaning company, myself,and 20 john does and jane does all got sued for $2.5 million each.and i didn't even work on it.now, for a few hundred dollars, you can purchase something that can'thurt anyone.how'd you like to try explaining to the district attorney that youreally didn't mean to electrocute anyone, you were just trying to savesome money?

author: slateraptor
author_rank: Frequent Contributor
timestamp: March 23, 2012, 11:27:11 pm
content: Quote from: FulThrotl on March 23, 2012, 10:47:04 pmOne of many outstanding reasons why I absolutely refuse to move to California.

author: Unknown
author_rank: Unknown
timestamp: March 23, 2012, 11:37:48 pm
content: Quote from: slateraptor on March 23, 2012, 11:27:11 pmThe state that banned black cars because they use more fuel? #OnlyInAmerica

author: slateraptor
author_rank: Frequent Contributor
timestamp: March 23, 2012, 11:48:11 pm
content: Quote from: Uncle Vernon on March 23, 2012, 11:37:48 pmCorrection: Only in California.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: March 24, 2012, 06:28:10 am
content: Hi Joshua, FulThrotl and othersI think you need to be safe and you need to be legal, unfortunately these are often two separate things and not one.Sparkies are often getting on their high horse about how they are the only ones who can wire things safely, I don't agree, I have seen quite a few cases of unsafe electrical practices/wiring which were generally due to sparky shortcuts.But it is often the case that Sparkies are the only ones who can wire things legally.From my experience many sparkies don't even understand the Aus/NZ electrical rules, mainly because they are written by lawyers anyway. Most sparkies work from knowledge gained by experience, which is a good thing, but quite a few actually have a very poor understanding of electricity. Cant speak for the US rules.I fail to see how isolated low voltage pool lights are any more dangerous than the pool itself. I think the fatality statistics would agree with me.In Australia sparkies are legally obliged to report dangerously defective work to the supply authorities. Fulthrotl's failure to do this may have been the cause of him being sued.Fulthrotl could you give us details of the court case and/or the event preceeding it? Did your insurance cover it?Ps. For the record , I am an Engineer/Sparky and I do have an interest in Electrical Safety. But I feel that the Australian Standards err on the side of covering their own backsides and not on the side of safety and definitely not on the side of small hobbyists who want to use electronics safely in their home. (Or in their pool.)