Is there a simple way to determine the light intensity / power output of an LED?
e.g. Light output = current x F.Voltage - heat dissipation Light output = efficiency x current x F.Voltage
I can't find heat dissipation, efficiency or similar on any datasheets. Only maximums. A few datasheets give mW/Sr or cd values.
No, light intensity is not, in general, linearly related to power consumed. You need to find the values in the datasheets directly, there is no way to calculate them given the sort of figures given on datasheets.
A calibrated integrating light sphere is used to measure total light in Lumens.
A calibrated Luminous Intensity meter at a certain distance can measure brightness in Candella. [Cd] or [mcd] If you want to make a crude sensor for making relative measurements, it must be color-corrected to CIE curve for human eye. This diode has such correction but by no means is accurate enough for important measurements, but it is handy for relative comparisons. They are very inexpensive and sensitive.
