Abstract
Monitoring operative conditions is one of the most important aspects of modern agricultural management. In order to improve data collection efficiency, it is necessary to develop an automated system that collects data on mechanised field operations and update the farm management information system (FMIS) database. Automation of operative monitoring is possible by adopting "field data loggers" (FDLs) installed in tractors working on farms. The present project is focused on the design, development and evaluation of a device based on wireless technology in order to identify the implements coupled to tractors. This allows automatic recognition of every mechanized operation carried out on the farm. The device consists of two main parts built with low cost commercial electronic components (hardware costs can be less than (sic)100): (a) a RF radio transmitter fixed on an implement that, on the 868 MHz frequency, sends aunivocal numeric code at predefined time intervals for every machine monitored; and (b) a receiver (integrated into the FDL), positioned on the tractor. Thetransmitter is triggered by a vibration sensor: so that the transmission of the machine code occurs only if the implement is in the working phase. This allows low electrical absorption (the life of the transmitter battery is estimated to be about 9 years transmitting two codes per minute). The device was implemented and evaluated in the field taking into consideration two different transmission power levels (PW 0 and PW 1) and three receiver positions: (I) on the left mudguard; (ii) at the top of the ROPS (Roll Over Protection Structure); and (iii) on the front of the engine's hood of two different tractors. This is done in order to determine the experimental horizontal 2D-beam patterns for every transmitter-receiver combination. Results show that, with the transmitter set at PW 1, all three receiver positions on the tractors can identify the rear and front coupled implements (2D beam patterns area ranges from 353.2 to 758.1 m(2), major axis ranges from 20 to 35 m and overlay index is equal to 100%) therefore, in order to protect the receiver device from incidental strokes, we selected the rear ofthe tractor cab as the best position to mount the receiver device.