Well my price range is pretty low... around $30USD.
I just want it to "count" the particles in the air every set amount of time, this is for my house.
As far as design goes i was thinking of a small laser with a magnifier and an optical sensor of some kind all in an enclosure that has a can pull the air through it.
Is this too much to ask for $30?
PS: i dont want to just go buy an air quality device