I am looking for a "cheap" => Less than $60 way to measure the amount of fog. It doesn't have to be an exact calculation.
I basically need to be able to differentiate between different amounts of fog.
Now I was wondering if a particle / dust sensor would do the job in my case: https://publiclab.org/notes/donblair/05-03-2014/how-do-we-measure-particulate-stuff-in-the-air or https://www.sgbotic.com/products/datasheets/sensors/datasheet-SM-PWM-01C.pdf
It seems like the perfect solution, but I'm not sure whether it filters out fog particles because they're not big enough.
The second datasheet states a minimum particle size of 1 um.
Now by googling "Fog particle size" it says "Most typical fog machines create a fog particle size of 1-5 micron."
That should be detected by the sensor module, but are real fog particles of the same size? And I assume these particles are only that big when the fog is really thick?