  Turbidity is a physical property related to the scattering of light by
particles that are suspended in a liquid. Commercial turbidimeters are priced
at the range of hundreds to thousands of dollars. Considering this scenario, it
is proposed in this work the development of a low-cost portable turbidimeter
for monitoring of turbidity in processes. An infrared LED was used as light
emitter, and an infrared phototransistor as light receiver. The signal
processing control unit was developed with the Arduino Uno platform. The
calibration of the turbidimeter was done by means of a comparative test in
triplicate, using as reference the commercial turbidimeter 2100P, HACH. The
turbidimeter was able to perform analysis in the range of 100 to 1000 NTU,
presenting an innovation character given its portability and computer
communication via USB, and in a good price range for the prototype, costing US$
46.30.
