Implementação de um tensiômetro digital utilizando microcontrolador dedicado

Abstract

The process of reading of the soil water matrix potential is a constant need of society. Different methods for obtaining exist, ranging from the tensiometers to complex digital systems. The present work consists of the inference of this measure through the automation process of the tensiometer reading which is the most conventional method , obtaining the tensimeter, utilizing, for that , a dedicated microcontroller. For the accomplishment of this procedure, it was necessary to couple a pressure transducer in the tensiometer for the pressure inside that ,could be obtained. Piezoresivity is the property that certain materials possess, being able to range a potential difference according to certain pressure applied. After this voltage is reached through the transductor, the signals were codified into digital data for them to be able to processed by the micro controller, which is a binary machine. The input voltage is conditioned into output of eight parallel bits with the use of an A/D converter. Then we have the input ideal for the microcontroller which processes data of eight bits. Available always, that byte in the input terminals of the microcontroller, there is a function which was implemented and recorded in the internal memory of the programmable integrated circuit, responsible for obtaining those signals, handle them, alternate them and present them as the principal output of the project , the measure of the soil water matrix potential .That is presented through two 7-segment displays, being able to range from 0 to 100 kPa. The work is, in short, the implementation of the interface and of the software utilized together with the microcontroller in the automation process of the tensiometer.