I need to set up a system with luminance sensors capable of reading fairly high brightnesses, on the order of 80 klx. We already use Si1153s as proximity sensors, so I thought it would be beneficial to reuse them in this application, since their datasheet advertises a range of 128 klx.
The catch is, the datasheet doesn't provide any information on converting ADC readings to luminance. I've seen other ambient light sensors provide a multitude of formulas to convert an ambient and infrared reading into a luminance value. I haven't found such a formula in the Si1153 datasheet, though, nor in some of the supplemental readings I've found.
How can I get from raw ADC readings to the measured quantity I'm looking for?
Minor correction for those well versed in this terminology, I meant "illuminance". Hopefully that was apparent from the choice of units.
Unfortunately, we no longer provide formulas to convert ambient light measurement result to LUX values. In fact, there's no simple formula to convert that, especially under different light sources.
However, we can provide a basic sensor configuration that you can apply under strong ambient light condition. We recommend you take measurements and calibrate against a light meter to generate your own formula to calculate LUX values.