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Adafruit LED Tape Lumen Data
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Adafruit LED Tape Lumen Data

by wforlines on Fri Sep 27, 2013 5:12 pm

Does anyone know any Lumen data (Such as a Lumens/foot figure) on the Analog RGB LED Tape Adafruit offers. It would be great to have a figure for both the "30" and "60" models. Though I can assume one is half/double the other.

Thanks much!
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Re: Adafruit LED Tape Lumen Data

by adafruit_support_mike on Fri Sep 27, 2013 7:14 pm

The datasheet for the WS2812 standalone RGB LEDs is probably as close to a spec as we have: http://www.adafruit.com/datasheets/WS2812.pdf

It lists the red LED at 550-700mcd, the green at 1100-1400mcd, and the blue at 200-400mcd. You'd then multiply that up to a per-foot value.

If you're doing anything other than full-on-white, you'll need to scale the LED values by duty cycle.
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Re: Adafruit LED Tape Lumen Data

by chrisw63 on Thu Nov 07, 2013 6:15 pm

So I assume you'd add those to get an approximation for full-white brightness? If so, using the median values for each LED, the total is 2175 mcd. With no emission angle on the data sheet, lumens cannot be calculated. Assuming a wide dispersion of about 120 deg., this figures out to about 6.8 lumen per LED, or 400 lumen per meter of the 60-LED tape.

Could someone with more experience confirm my assumptions / calculations???

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Re: Adafruit LED Tape Lumen Data

by adafruit_support_mike on Fri Nov 08, 2013 5:16 am

There are several ways to calculate brightness. The objective brightness is a weighted sum of the RGB components. The perceived brightness is the root-mean-square of the RGB components. The effective brightness is simply the value of the highest component.

The lighting spread is very roughly spherical, with one edge of the sphere tangent to the LED itself. The calculations after that get pretty hairy.
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