I am currently working on a project that uses the Sparkfun AS7265X to measure atmospheric light levels. However after going through the appropriate data sheets, I could not find the meaning (units) of its readings.
The sensor provides raw and calibrated readings for 18 different wavelengths of light. Can you please explain how these calibrated readings are converted to scientific units. Also, will the parameters like the gain effect the readings ?
Thanks
It’s a measure of ‘spectral response’ of counts/
(μW/cm2) measured across 18 frequency bands of the EM spectrum; go through this https://cdn.sparkfun.com/assets/learn_t … asheet.pdf pgs 14-15 for an explanation of how the sensors are calibrated (you should be able to easily convert to/from other units @ a given distance), and this https://learn.sparkfun.com/tutorials/sp … okup-guide for a general guide
Higher gain values increase the amplitude of the peaks (essentially they multiply/divide the count/cm^2 by whatever setting is chosen…say, 16x, 4x, etc) - think of it like ‘sensitivity’. Get the sensor working and adjust the gain if your data is too high/low to be useful
Thank you for the reply. So, just to be clear, for example, if I get a reading of 20 from the self.getCalibratedA() method, that would be 20 counts/(μW/cm2) ?
Yes (after whatever internal rounding error there might be)…with a slight caveat, the equation is “counts (uW) / cm^2”