Add lux calculations to the LTR-329ALS sensor class

[amcewen]

The light sensor on the pySense boards reports two light values from the LTR-329ALS sensor.

Reading the datasheet for the sensor that's because there are two sensors sensitive to different wavelengths of light.

The datasheet mentions that there is a formula for calculating the lux level from those two readings. It would be good to have the lux reading available from the LTR329ALS01 class as well as the raw light readings.

[amcewen]

The datasheet doesn't actually include Appendix A, but i received a copy of it from LiteON when I asked them about it.

I've implemented the new method in my fork of the libraries, in mcqn@3faed57

Happy to submit a pull request, but at the moment I've already got PR #95 outstanding, so it looks like that would need to be accepted/rejected first?

[Kriskras99]

Your implementation does not work if light_level == (0, 0), because the ratio calculation would be a division by zero (ZeroDivisionError)

[amcewen]

Yes, sorry I forgot to update this issue - that bug was fixed in the next commit to my fork - mcqn@8d655f9 - a few weeks later.

[osmoralv]

Hello @amcewen , could you share the file with the formula please?, I am working on a Light sensor using the LTR-329ALS-01 on my job and I need a reliable reference for my programming algorithm. The work will be share on github in C language and libraries for PIC mirochip microcontrollers. I really appreciate your help.

[JobStokkermans]

Hello @amcewen Could you share appendix A with me? I am working on the LTR-329ALS-01 as well.