HOW TO – Build a 1,024,000 mcd portable light

2 thoughts on “HOW TO – Build a 1,024,000 mcd portable light”

1. enenome says:

   February 16th, 2006 at 9:39 am

   LEDs are current sensitive devices. You can regulate the voltage all day but it’s current that’s important. This LED array is bright indeed but all LEDs vary, and have different requirements, regardless of quality or type. In this specific case, you’ll tend to cut the life of the LEDs by overdriving them.

   I know that some might think that pulse with modulation (PWM) might be better solution “but” when using with white LEDs, PWM dramatically reduces the life of the phosphor. PWM does have its advantages in portable devices but if you’d like to have the most efficient LED array, use resistors and proper power source and avoid PWM if possible.

   I dislike being so critical when it comes to others work but a 1+ million MCD rating is inaccurate. Adding up the LED count based on their millicandela rating won’t give you the real output of your LED array. Since there isn’t an “easy” way of converting lumens to watts, it makes measuring LED light, for most, very subjective.

   One more comment and I’ll stop.

   Stay away from resin. You’re pushing heat through these LEDs and even more than you’re not using current limiting resistors. Heat will expand the resin allowing for moisture to creep in, especially if you are using this light in a moist environment.

   When you turn off the LED array, moisture will be trapped, in turn, shorting the LEDs and ruining your work. I’ve found that if you must seal your LED arrays, try silicone rubber. Yes, it’s more expensive but it “breathes” and allows you to get to problems easier than resin.

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