Da_monkey Posted April 10, 2015 Report Share Posted April 10, 2015 Hi guys i have been experimenting with Led lighting for some time and i want to try to make something worth while. I've always wanted to have a computer controlled high powered led light system for my tanks / plants looking around i've found that these are usually really expensive. and even normal led lighting are either expensive or just have red/blue leds. So far I've built my own leds lights with out control but they use off the shelf Laptop chargers which you can get cheap but not if you want the same one twice. here is my latest design using a switch mode power supply for maximum efficiency. Each dome is 4 *3 w leds from aliexpress for 24w over the tank it uses the laptop power supply to get 15V then uses the small green circuit on the back to drive the leds at 666mA or close enough to 700ma they want. they can take a signal from a micro controller to turn them on and off so they can do PWM dimming or by using a set voltage between 0 and 2V the current can be dropped this is a pain in the ass to get so pwm is what im going to do. The shade is a small cake tin also from aliexpress and i got the heat sink to match. A few quick holes and sanding of the base and they screwed together nicely. The LEDs are thermal glued in which was a bit lazy of me but it works I plan to attach these to a TI launch pad i have and use that too act as an interface to a Wifi controller. The wifi module i have is an esp8266 wifi module again from aliexpress. It is $3 so i'm not sure how true the FCC and Other test markings are. but it doesn't matter for me but if i have problems i may have to change to a nordic semiconductor or TI wifi module which is a lot more expensive but they are most definitly ok to use. this will then talk back to a central computer which has the user interface on it. i have the main design laid out but getting the details set out will take some time. I want to be able to put circuit diagrams and some psudocode up some time soon. I already have the LEDs from aliexpress i got 1000 1w leds and 200 3w leds the 1000 1w leds are for a neat circuit for driving them from mains where you bypass the leds as the voltage drops and then add them back in when it goes up. i haven't got a proper plan worked out yet but will get it done tonight. It does have a micro controlling it so will need to get creative with voltage levels but thats part of the fun. It does effectively half the lumin output of the leds but at 3cents each i cant complain(http://www.aliexpress.com/item/Free-Shi ... 02403.html they took a while to get here) There's an off the shelf component for it but it only works up to 100ma where i want more as 1w leds use 300mA and 3w 700mA If any one has experience driving large loads from mains advice would be great. i have ideas but this will be my first project that takes mains power directly. If any one is interested i can go through making a 100W led fixture from a laptop power supply and some reasonably cheap components. Please look forward to more updates as i go Quote Link to comment Share on other sites More sharing options...
kinnadian Posted July 3, 2015 Report Share Posted July 3, 2015 Those cheap led drivers fail really easily, I tried experimenting with them before and they were pretty bad. Get a more reliable one or you might come home one day to a fire... Also with those really cheap LEDs you get what you paid for, they have very weak output and lumens are nowhere near 1W from a decent LED manufacturer. They are quite inefficient. Plus soldering in all those LEDs will take forever. You are better off with a smaller amount of decent Cree LEDs from Ebay, they cost about $2/ea shipped from Ebay and are well worth it. Also you need to consider cooling, LEDs generate a hell of a lot of heat. At the very least you will need a large aluminium heatsink, if you are doing 100W you will probably need a cooling fan. Quote Link to comment Share on other sites More sharing options...
livebearer_breeder Posted July 14, 2015 Report Share Posted July 14, 2015 True Cree LEDs are worth purchasing from a reputable supplier you can almost guarantee that a "CREE LED" that only cost $2 off ebay is not a true Cree. Even just get yourself some cheap HO 3w epistar or bridgelux leds off ebay to mess around with, they are only about 10% over all less lumen output than a cree model anyways. Quote Link to comment Share on other sites More sharing options...
Da_monkey Posted July 16, 2015 Author Report Share Posted July 16, 2015 They last well enough for the speed i go through fixtures. I do agree if i was going to make something for some one else i would definitely go with Cree or Panasonic(cree wins on price by a lot atm) . though i would go through RS components or digikey rather than some ebay seller. Interesting Fact Cree is actually a start up from a university where they use a different sub strait for there LEDs than the other brands Im planing to eventually use something along the lines of this one http://www.digikey.co.nz/product-detail ... ND/4036264 Its cheap and powerfull though doesn't have a dedicated thermal pad. They other thing is always run LEDS from a constant current supply or stay bellow the rated voltage. heat sinking is not as bigger problem as its made out to be. 1W Leds can run on Ram heat sinks not much bigger than their base and not have much problems. for the really small ones like the example above a chunk of copper or aluminium is needed to spread the heat out before it reaches the heat sink but aluminium is cheap. fans are going to be needed but i'm not too worried as most aquarium hoods have more than enough space. for low profile designs an external power supply can be used allowing the isolation from the LEds to the heat sink/environment to be minimal Quote Link to comment Share on other sites More sharing options...
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