ATMEGA32 microcontroller based conductivity measurement system for chloride estimation of soil samples

This paper presents the development of an inexpensive and portable microcontroller based instrument set up to measure the electrical conductivity of the soil samples and hence to determine the Chloride concentration using empirical relation between the two parameters. A dedicated ATmega32 microcontroller and its associated peripherals are employed to measure electrical conductivity and temperature. A special feature of the designed instrument is that the conductivity temperature compensation can be achieved by software or the user can maintain the sample at desired temperatures by using the temperature controller. An empirical relationship between Chloride concentration and electrical conductivity of soil samples has been developed using Linear Regression Model, which gave a Correlation Coefficient of R = 0.95 ( n = 20), Slope = 14.95, and Intercept = −563.9. The obtained results are compared with the ELICO CM 180 conductivity meter to check the accuracy of the designed instrument, which gives a correlation coefficient of R = 0.98 ( n = 20).