Elaboração de um pluviógrafo com sensor ótico

Abstract

This paper objective was to develop a pluviograph with an optical sensor. The chosen modal to be developed was the bascule type for being versatile for the automatization process. To build the bascule, galvanized material was used. Te bascule, for precipitation measurement, has a sensibility of 0.3mm of liquid, that is, for every 0.3mm of rain precipitation there is collected water rejection and optical sensors, made of emission-receptor sets, send out pulses that are registered by an electronic counter and by a Personal Computer (PC). To build the receptor surface a 200 cm2-collecting ring was used and it is one of the most important parts of the instrument. This 200 cm2-receptor area is one of the most employed among pluviographs used in the country. The bascule system components were structured with bolted, removable parts without the use of soldering so it wouldn t cause deformity and to facilitate adjustments during building and testing. The electronic counter totals precipitation amount through the number of operations of the bascule system that are shown in a display. Through its parallel port, the computer uses a routine program and registers the amount of rain precipitation with the help of a transductional circuit. The computer software was developed in Visual Basic platform and named Monitor. On the computer screen, a table with the record of the 12 last operations performed by the bascule system is shown, and next to it, a three-indicator bar chart shows precipitation that occurred in the last minute, the last hour and in the last 24 hours (day). To validate the workability of the instrument, for comparative measurements, other two instruments were used: a Ville-de-Paris Conventional Pluviometer and a R. Fuess Siphon Pluviograph with readings taken at 9 AM. With these references, a considerable good performance was obtained, showing the record of the precipitation phenomenon with good regularity, which falls within this research expectation. Error relative to precipitation quantity pattern during measurements fell between 0mm and 1.9mm intervals. Error relative to the R. Fuess Siphon Pluviograph fell between 0mm and 2.1mm intervals. The least intense precipitation registered during this period(03/03/2006 04/14/2006) was 0.3mm, whereas the most intensive was 57mm.