A Data Acquisition System for Evapotranspiration Measurement in Remote Fields Using Mobile Telephone and Small DC Generator

A system is developed using a mobile telephone to continuously measure evapotranspiration in remote fields over long period and transmit the collected data. The necessary electric power for the system is supplied by a propane gas-driven small DC generator (approximately 24W). Evapotranspiration and micrometeorological elements are automatically measured every minute by a 16-channel data logger. After 10-minute averages are calculated the data are stored every ten minutes in IC card which has storage capacity of 11 days of data. The software for transmitting data, calculating evapotranspiration rates, printing graphs and others is written in BASIC. The average time required for transmitting data for one day was approximately 4min. The functions and applicability of the system were examined for a total of approximately 20 months from 1992 to 1994. It was found that the system developed is simple to operate and effective for collecting data in remote fields.