Designing and Building a LED Fixture

[malaybiswas]

Originally Posted by Hoppy

I noticed in reading other threads on other boards that adding a color can give different effects than you expected. That was why I started with just white ones. Also, it would probably be best to look for a LED that gave a color more like the red-violet of the 9325K bulb, rather than red. Finding that wouldn't be easy.

That would take a lot of experiment. Fortunately you may be in luck. I am just hooked enough to this hobby now and want to try new things with LEDs and circuits. I plan to get some more LEDs (colored ones this time) and try out color mixing and auto dimming. No time limits, but may be I can produce some results that can come handy to others.

[Hoppy]

Nothing but disappointments today. First, DealExtreme has not shipped my LED order, even though 10 days have passed since I placed the order, and they don't respond to my email asking for the reason for the delay. Then, I wasn't able to locally buy the parts needed for my DIY drivers, so I had to order them on the internet - with the shipping charge greater than the parts cost.

DealExtreme scares me a bit - the prices are so low I worry about their legitimacy, except others have reported good results with them.

[Cactus Bastard]

I've bought about a dozen things from dealextreme in the last year or so, sometimes it does take them a while before parts ship. I've had parts take up to five weeks before they ship out.
Still can't beat their pricing :P

[Hoppy]

I suppose the slow shipping is the price we pay to get the great sales prices. They do advertise a much faster shipping process than that, but who believes advertising anyway.

I found a little circuit board at Radio Shack that will fit my LED Driver circuit very nicely. It is only 1 7/8 by 2 7/8 inches, with a very usable layout of conductor strips and holes on it. Here is the layout I'm planning on using, unless I find errors in the next couple of days, as I wait for the semiconductor parts I had to order:

[malaybiswas]

Originally Posted by Hoppy

Nothing but disappointments today. First, DealExtreme has not shipped my LED order, even though 10 days have passed since I placed the order, and they don't respond to my email asking for the reason for the delay. Then, I wasn't able to locally buy the parts needed for my DIY drivers, so I had to order them on the internet - with the shipping charge greater than the parts cost.

DealExtreme scares me a bit - the prices are so low I worry about their legitimacy, except others have reported good results with them.

None of the online dealers normally stock large quantities of specialty products. If you are buying in bulk they will normally back order. I bought my LEDs directly from Luxeon but still had wait times of 2-4

[kev82]

Originally Posted by Hoppy

Nothing but disappointments today. First, DealExtreme has not shipped my LED order, even though 10 days have passed since I placed the order, and they don't respond to my email asking for the reason for the delay. Then, I wasn't able to locally buy the parts needed for my DIY drivers, so I had to order them on the internet - with the shipping charge greater than the parts cost.

DealExtreme scares me a bit - the prices are so low I worry about their legitimacy, except others have reported good results with them.

They are legit. I've ordered probably 10 times in total from them, all sorts of products (flashlights, batteries, rc helicopter, servos, LEDs, digital calipers, toys etc) and everything has been shipped eventually. It usually takes them at least 3 days to ship, but often ~10 days. It took them about 2 weeks when I ordered the crees.

[Hoppy]

OK, I'm reassured that my LEDs will arrive eventually. That company is one great resource for LED products, so I suppose I will just have to learn patience. Oooooooom! Oooooom!

[Cactus Bastard]

Originally Posted by Hoppy

Oooooooom! Oooooom!

Is that your patience noise?
I think it was my P7s that took over a month to ship, and I was probably making some similar noises during that time, maybe with a bit of gurgling and the occasional squeek

[Hoppy]

Originally Posted by Cactus Bastard

Is that your patience noise?
I think it was my P7s that took over a month to ship, and I was probably making some similar noises during that time, maybe with a bit of gurgling and the occasional squeek

Hey! It worked! My LEDs have been shipped and should arrive in 7-10 working days. Remember the magic chant: "Ooooom oooom...."

[Hoppy]

My plans have changed again. The task of switching my light enclosure from an AHS light to the LED light would take me as much as 3 days, and if the LED lights don't work or don't work as well as I hope, I would have to switch back, but the enclosure would by then have too many holes in it, so......I'm going to just make a new enclosure so I can assemble the whole thing at a more leisurely pace, test it, make any needed corrections, etc. before switching the lighting on the tank. This adds only a few dollars to the total cost, and makes the whole project infinitely more workable. I don't see how we can ever have a LED mod kit that is "plug and play".

Right now I am struggling with the assembly of the DIY driver - soldering all of those tiny, tiny connections takes a lot of practice. Electronics assembly is a job for 2 foot tall people with proportionate sized hands and fingers. Hmmmm, I wonder if I can borrow my great granddaughter for a few hours???

[kev82]

What driver did you decide to use?

[Hoppy]

Originally Posted by Hoppy

Here is the schematic for the constant current "driver" I plan to try to make today:

This is the driver circuit I am making, from Instructables.com, but modified a bit to suit my situation.

[Hoppy]

I'm making a wood housing for the LED light now, using a 2' x 4' 3/8 plywood panel from HD. It is 5 ply plywood, so it's a bit better quality than usual, but still just plywood.



I use a "Skilsaw" to cut most of the parts, using a clamp-on straight edge to guide the saw for a straight cut. And, a power miter saw to cut the 30 degree angles on the end pieces, for accuracy. The plywood is just glued together with "carpenters glue", ordinary yellow glue, which is stronger than any nails or screws anyway. The clamps shown are just there to balance the half assembly to make gluing on the 4th piece easier. Masking tape is an adequate clamping device to hold it until the glue sets up.



This is with the front, back and ends glued together, with small triangular glue blocks in the corners to reinforce the joints so the end grain of the plywood isn't all that holds it together. I have the top glued on too, and have started sanding it all even with a belt sander, but I ripped the belt, so tomorrow I get back to work on it.

[kev82]

Looking good, do you have bigger pics of the joints?

[malaybiswas]

nice job. how are you planning to set this up? hang it over the tank or mount it on the tank?