mar 7, 2009 - Congressos    1 Comment

WCCA 2009

O WCCA (World Congress on Computers in Agriculture) é um congresso internacional que provê um fórum para profissionais da área trocarem informações sobre novas aplicações e tecnologias na área de Informática aplicada a agricultura. O evento abrange uma grande variedade de tópicos, com contribuições de vários países, permitindo uma perspectiva ampla dos assuntos discutidos. A edição de 2009 será em Reno, Nevada, EUA, entre os dias 22 e 24 de junho de 2009, e contará com quatro artigos meus e da minha equipe. Leia os resumos a seguir.

Topology of a network for wireless transmission of data for use in precision agriculture

Alex Lemes Guedes; José Alexandre de França; Marcela Hitomi Koyama; Maria Bernadete de Morais França; Marcelo Giovanetti Canteri.

Weather conditions influences the plant disease progress. Precision agriculture, besides variability of soil, could measure meteorological variables like wetness and temperature for monitoring plant pathogens infection periods. This assessment is carried out in many points of crop area and data set could be sent remotely to a device called “coordinator”, using a cable as transmission line. However, a cable network in a crop area has a high cost and presents operational difficulties. The objective of this work was to develop a wireless data communication between meteorological stations. The “coordinator” device has total control over the network. It asks for data to be transmitted and which station will receive the data, creating a communication system type question/answer. The network also incorporates the multi-hop concept, where the data do not need to be transmitted directly, but through routers, increasing the depth of the network. This logic was implemented through the local address of each device. Prototypes of meteorological stations using microcontroller were built to tests the system. The results showed that the network work satisfactorily when the distance between meteorological stations was 1800 meters or less. This enables them to be installed throughout a crop area.

System of microstations of data acquisition for wireless monitoring of the microclimate in crop areas.

José Alexandre de França; Edson Luiz Burgo Júnior; Marcela Hitome Koyama; Rodger Vitória Pereira; Marcelo Giovanetti Canteri; Maria Bernadete de Morais França

The weather conditions are a key factor for outbreaks of plant diseases. Therefore, the monitoring of climate is essential to any intelligent system of cultivation. Usually, such monitoring is carried through agrometeorological stations that acquire data like temperature, humidity, wind speed and leaf wetness. Unfortunately, the high cost of stations limits the number of monitoring points within the same area. This forces the use of tools of mathematical interpolation. However, such procedure does not lead to good results in the estimation of precipitation and leaf wetness. In this work was developed a monitoring system, composed for a set of microstations of data acquisition. They presented low cost and highest autonomy. Therefore, they can be installed throughout the area of cultivation, collecting data like temperature and leaf wetness. The microstations communicate with each other through wireless communication. Thus, daily, the data collected are transferred to a central station, where become available for analysis. The system made it possible to monitor the entire area of cultivation, providing reliable data, which make it possible to characterize the microclimate. This makes it possible to, for example, the efficient use of pesticides, reducing production costs and generating healthy foods.

Anemometer 3D based in ultrasound

Marcela Hitomi Koyama; Rodger Vitoria Pereira; Tiago Polizer da Silva; José Alexandre de França; Marcelo Giovanetti Canteri; Dari Oliveira Toginho Filho

The wind speed influences the development of the plants, being able to modify its growth, reproduction and distribution in the field. Moreover, the wind can spread plant diseases, carrying pathogens spores. Therefore, the measurements of the speed and direction of the wind are useful in agriculture. Usually, this measurement is made using anemometers in set with wind cocks that act in only two dimensions, measuring the speed and the direction of the wind through a mechanical system. The disadvantage of this approach is the existence of mobile parts that render not accurate measures of speed, due to friction with the air and the inertia of the equipment. In this work, an ultrasonic anemometer is presented that measures the direction and the speed of the wind in the three dimensions. Such anemometer uses only four piezoelectric sensors arranged in two orthogonal axes not competitors. So that, joining together the points of each sensor was get a structure in the form of a regular tetrahedron. The speed of the wind in the three directions can be measured inferring the necessary time (transit time) so that a pulse of ultrasound, sent for one of the sensors, reaches the others three. Moreover, the tetrahedron-shaped structure allow to measure in six different coordinate systems. This adds redundancy to the problem so that, even considering an uncertainty of 5% in the construction of the anemometer, get to be an error of just over 1% in wind speed. This measurement is performed by a microcontroller and is done to make the system immune to variations of temperature and air humidity. The microcontroller is also responsible for storage of data and later sending them to a microcomputer.

An online humidity transducer based on near-infrared radiation

Diogo Kaoru Takayama; José Alexandre de França; Dari Oliveira Toginho Filho; Maria Bernadete de Morais França; Marcelo Giovanetti Canteri
In various sectors, humidity measurement is a crucial task, for instance in the food industry, grain processing/crushing, sugar plants, etc. The conventional humidity measurement method requires a lab sample analysis. This is a destructive, expensive and slow process. Besides, as raw material humidity may vary considerably during the day, many measurements are required throughout the period. On the other hand, with an online humidity measurement process, the water amount is known instantly, without physical contact with the sample. Thus, the production process control can be carried out without losses, with maximum profit and quality. In this work, a humidity transducer based on near-infrared radiation is presented. During its development, the main project focus was cost reduction. Due to this, LEDs were used for producing infrared radiation. This has eliminated typical problems in conventional online measurement tools, such as reduced useful life and too many moving parts which may complicate equipment installation in vibrating places. Through the inclusion of a temperature control system, problems with ambient temperature variation were solved. The equipment was tested on a laboratory, measuring coffee powder humidity. However, the system can be easily adapted to measure humidity on a variety of other substances. Our tests indicate that the proposed transducer has a high sensitivity and robustness to temperature variations and external radiation sources (solar and incandescent light, etc.) Besides, the measured equipment uncertainty is in the order of 0.2%.