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OPT3002: How to measure direct sunlight

Pedro Rodrigues
Prodigy 10 points
Part Number: OPT3002

Tool/software:

Hello,

We are looking for a sensor that could help us distinguish ambient light. Specifically we are trying to assess whether someone is under direct sunlight or not. To do this we were thinking about using the OPT3002, would you recommend something else? 

We saw that OPT3002 can measure a part of the UV spectrum and were thinking about determining whether someone is under sunlight depending on some threshold calculation. 

It is important to mention that OPT3002 will be soldered on a PCBA that is enclosed in black pastics. The only way in and out for the light is a light pipe that is directly on top of this sensor. What do you recommend in terms of material for this light pipe?

Thanks,
Pedro Rodrigues

  • 0
    TI__Expert 4020 points

    Hello Pedro, 

    Thank you for using the E2E forum. 

    OPT3002 should be a sufficient choice for your application, but it is important to recognize that this is a broad band ALS that has its response as shown extending beyond the visible spectrum:

    You will need to determine appropriate limits to discriminate between direct sunlight and other conditions, these limits should be determined with the light pipe utilized. This is because light pipe will cause some attenuation, and this will need to be known to correctly set limits. 

    This video is an overview of light pipe applications: Extending light sensor field-of-view with lenses, diffusers and light pipes

    We don't have specific material suggestions to offer for light pipe choice. The most important factor will be unit to unit variation of the light pipe, you should choose the light pipe with lowest specified variation for best results.   High variation between light pipes may necessitate unit to unit calibration to obtain desired results