Alone under LED illumination ;)

2011-04-23

Admitedly, I’ve always been interested in LEDs. High intensity LEDs across the entire visible spectrum are easily available nowadays, so providing a science fiction spaceship look to the house was tempting enough :)

LED decorative lights10W White LED with heat sink

Still trying several things, but these are a few conclusions so far:

RGB LEDs (composed of three smaller LEDs) can emit light in any colour by mixing the three primary, and theoretically one could build a wide set of lighting effects with them. The big limitation is in the controllers, though. Commercially available controllers (also known as dimmers) for RGB LEDs are cheap but usually quite boring, in the sense that they offer no more than fixed colours and very limited blink or shading effects to choose from. Not a big surprise. It would be much more fun to have programmable controllers, or at least a wider set of options built-in.

A very interesting additional possibility would be to attach sensors or timers, and fade, switch colours or adjust intensity depending of time of day, day of week, outer temperature, music played in the room, or any other event. I’m sure that many people reading this are thinking about the Arduino, and me too.

Some sort of computer interface will allow to reprogram or control illumination parameters through a network connected tablet. And what about a webcam? We could detect motion events within a room and make the LEDs react to them… So, once again, it seems unavoidable to construct something. Please feel free to drop a comment if you know a better RGB controller already available, something hackable, or have an idea for making one.

On the other side, very succesful results were achived using “warm white” (around 3500K maybe) LEDs for general illumination. The color rendering index seems to be poor, though it shouldn’t be a problem for ordinary usage.

A floor lamp was modified to hold 3 10W LEDs and heat sinks inside. Actually, each LED appear to be internally composed of 9 smaller LEDs packed under the enclosure. They are OK too, but I think I prefer large arrays of lower intensity LEDs, seems more practical and they don’t need those huge heat sinks. Those 3 LEDs alone give a perceived light that’s maybe comparable to 150W halogen lamp (imprecise measurements done with a basic lux meter). It could be better if they weren’t running under an electric current below the specified maximum, because I’m not completely confident about the heat sink capabilities. The actual consumed power depends very much on the efficiency on the power supply plus power loss in resistors or intensity limiting circuits, but very efficient overall.

Filed under: Hardware

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Alone in the Light


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Roberto Gordo Saez

roberto@zenvoid.org

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