TSL320 output!!

drnilles

Hi all stampers,
I'm in need of some assistance on how to use the TSL230's Freq output. I
would like to convert it to candle power or Lumes. Sadly my math is lacking.
Any help will be appreiceated.
Thanks in advance,
Don

PJAllen

Having read the datasheet, you know that the TSL230's output (frequency) is an indication of irradiance, the intensity of light on the sensor.· Candlepower, lumens, are measures of the output of a light source.· The relation of the candlepower of a light and the irradiance measured by a remote sensor would be a function of distance (basically.)·

It's a matter of a·lamp's brightness, it's output,·and its perceived brightness some distance away; it could be so bright as to drive you away·if near, but just some interesting spot if several hundred feet away.

Post Edit -- Here's an excellent web-page which addresses this very matter:
http://www.padfield.org/tim/cfys/lightcd/lumen.php

Post Edited (PJ Allen) : 4/19/2008 5:21:48 PM GMT

drnilles

Dear PJ,
Thanks for the help!
Don

PJAllen

I've been looking to see how to convert from uW/cm² to lumen/m², but I'm coming up short.· [noparse][[/noparse]There's lumens for luminance, emitted light,·and illuminance, light on a subject (lux).]

Tracy Allen

From a MicroSemi data sheet:
The most sensitive wavelength for the normal light adapted human eye is
555nm. At 555nm, the conversion factor is 683 Lux =
1W/m2 = 100μW/cm2.

(lux = lumens per square meter, or, lux = candlepower * 10.76)

Sunlight is about 1E5 lux, moonlight about 1E-2 lux.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Tracy Allen
www.emesystems.com

PJAllen

OK, good deal.

If anybody's following along, Taos·emailed me the attached Design Notes.

Enjoy (or something.)

drnilles

Thanks again, guys
Don