A low-cost temperature controlled system to test and characterize sensors

Almost all parameters (physical and chemical) used for in-situ water quality monitoring of rivers and seas, are measured using sensors that have characteristics highly sensitive to temperature. The objective of this paper is to present the project, design and implementation of a low cost testing bath with automated temperature control for environmental monitoring sensors characterization. Besides the description of the overall testing system, the paper details the cooling and heating thermoelectric pump based on Peltier modules implemented for the temperature control of the liquid, the tests that were conducted in order to obtain its optimal performance, the set of sensors and their signal conditioning to measure the temperature and the digital proportional-integral-derivative (PID) algorithm implemented in LabVIEW to control the temperature of the bath. The developed testing apparatus proved to be an efficient tool to test and characterize sensors for in-situ water quality monitoring.