I’ve been playing with LED lighting in the past six months, and finally bit the bullet, pulled the trigger, and purchased enough LEDs, micro-controllers, motor controllers, and power supplies to replace the under-cabinet lighting in my kitchen (which has always sucked) and the aquarium lighting in my two aquariums.
There are LOTS of LED alternatives out there, but, after buying about a dozen different samples, I went with “10W White High Power 800LM LED SMD Lamp Bulb” sold by eBay seller “ac-rc” from Hong Kong, eBay item number 270588087597 as of early March 2011. They go for about $10 apiece, and compatible power supplies are cheap ($20 for a power supply that will handle 10 LEDs). These little postage-stamp sized LED devices put out a blindingly huge amount of light, and can get very hot. You need to mount them to an aluminum heat sink if you to avoid burning them out. While they are rated at 12 volts (which is what I will be using for the aquarium applications), if you run them at 9 volts (which is what I’m doing in the kitchen), they only get a bit warm (but still need heat sinking). I’m still playing with how much of a heat sink you need for continuous operation.
They sell different “color temperatures”, and I’m using “white” in the kitchen, but a more blue (10K) for the fish tanks. I will use an Arduino micro contr0ller (http://www.pololu.com/catalog/product/1614) and a motor driver (http://www.pololu.com/catalog/product/755) to create an artificial dawn and dusk.
It turns out that one of these LEDs every 12 inches is enough to provide good under-cabinet illumination, and there is enough dispersion that you do not need to aim them indirectly or use a diffusion device. I’ll be using 3 of them for the 2 foot wide sink area (rather than 2) because of the increased distance. The assembly is so thin that it can be mounted under the cabinet and still be hid by the under cabinet lip; much better than the old fluorescent lights.
Total cost for the under-cabinet lighting system is about $180; the smaller aquarium should cost about $200, and the larger one about $300. Given that LED lighting systems for aquariums can run over $1000, I’m pretty pleased with the idea. Of course, it is not done, yet, and some challenges remain (such as device cooling and concerns about salt water spray).
I’d be happy to talk with you about your LED project if you have questions.