Sistema de telemetria para aplicações no campo agrícola.

Abstract

This work describles the development of a telemetry system for data acquisition in Precision Agriculture. The topology of this system is based on a star struturc with a central unit and several remote units. The communication link between the central unit and remote inuts uses a wireless frequency modulated (FM) carrier. The digital information is carried over the communication channel using a frequency shift keying (FSK) modem. The remote unit is responsible for data acquisition from field sensors. In it's core, na embedded microcontroller (Motorola 68HC11) is responsible for managing data acquisition, control and communication protocol. A FM transceiver was developed to allow simplex, half-duplex ou full-duplex communication. The remote unit circuitry was designed for low power consumption, and is powered by a solar panel in combination with a rechargeable battery. The central unit utilizes a PC, under DOS environment. A supervision software was written to display field data, make decisions, and to send commands to the field. The same FM transceiver and FSK modem were also employed by the central unit to communicate with the remote units. A data protocol, based on broadcast communication, is used for synchronization and error detection. The system was experimentally implemented in a proof-of-concept design, and satisfactory results were obtained in it's functional characteristic, including communication, protocol, data acquisition, and solar power.