Aplicação de sensores de baixo custo na quantificação de CO2 em processos biológicos

Abstract

This research proposes to use alternative materials that simplify the production of Gas Volume Meters, which act in the generation of bubbles by the displacement of a liquid inside. Sensors and microcontrollers are used to count the number of bubbles generated and present the information in spreadsheets and graphs. The use of a capacitive sensor was decisive in the accuracy of detecting bubbles, without having to come into contact with the measuring fluid. The glass body, widely used in other projects, was replaced by acrylic material. The electronic components management software was developed in Node-Red, its graphical interface is simple and user-friendly. The improvements involved in the project include scientific research institutions that use volume meters to investigate biological processes that produce some type of gas, such as alcoholic fermentation and biogas, whose availability of financial resources is limited. All the improvements applied in the project make the gas volume measurement process automated, presenting information and production data in real time. The cost of each Volume Meter was US$ 30.38. The control module had an estimated cost of US$ 222.70 and can manage up to 12 Volume Meters simultaneously. The amounts involved are low compared to professional equipment available for purchase. The data on the volume of gas produced in the tests proved to be consistent for all Volume Meters evaluated, comparing with the volumes measured in the beakers. The analysis of images of the gas bubbles produced, applying the area calculation using the ImageJ software, proved to be effective to attest to the reliability of the results. The equipment is suitable for use in small-scale biological process gas production applications, usually in the laboratory.