From: pcdhSpamMeSenseless@electrooptical.net   
      
   Marcos Loyola wrote:   
   > Hello good day! I need a simple circuit to detect the turbidity of   
   > the reuse water from the washing machine, that is, discard the 1st   
   > water and reuse the others, a very simple circuit for a low-income   
   > community. Thank you Marcos   
   >   
      
   On a good day, you can measure the turbidity using an Arduino, a LED, a   
   phototransistor, and a resistor.   
      
   The problem normally has more to do with how to keep the optical window   
   clean.(*)  That might be easier with a clothes washer, because the flow   
   is pretty strong and frequently has a lot of detergent and bubbles,   
   which should help.   
      
   It'll need some experimenting, though.   
      
   How high-tech is your setup?  I assume you have a storage tank, but how   
   does the water get in and out, and how is that controlled?   
      
   Cheers   
      
   Phil Hobbs   
      
   (*) If you have the time, and a nearby library can get a copy, Mark   
   Johnson's "Photodetection and Measurement" is an excellent read.  Mark   
   was the head of quality assurance for a bit water utility in England,   
   and really knows turbidity measurements.  A lot of it is quite   
   accessible at hobbyist level.   
      
   --   
   Dr Philip C D Hobbs   
   Principal Consultant   
   ElectroOptical Innovations LLC / Hobbs ElectroOptics   
   Optics, Electro-optics, Photonics, Analog Electronics   
   Briarcliff Manor NY 10510   
      
   http://electrooptical.net   
   http://hobbs-eo.com   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)