On-chip integrated silicon bulk-micromachined soil moisture sensor with electro...

• Autor(es): Valente, A. ; Correia, J. H. ; Couto, Carlos
• Data: 2000
• Identificador Persistente: http://hdl.handle.net/1822/4860
• Origem: RepositóriUM - Universidade do Minho
• Assunto(s): Soil moisture sensor; Bus interface
• Tipo de Documento: Documento de conferência
• Idioma: Inglês

Descrição

This paper presents an on-chip silicon bulkmicromachined Soil Moisture Sensor (SMS) for irrigation control in greenhouses. The system-on-a-chip includes the SMS, readout electronics, self-test, calibration facilities and a digital bus interface for external data transmission. Moreover, this low-cost device can be applied in several locations (e. g. per each plant root), and networked together with the 1-wire bus. The heat-pulse technique is used (for measuring the maximum temperature on a distant point) to determine the volumetric heat capacity and hence the water content of a porous media, such as soil. In order to validate this method, experimental results were achieved with a macrosensor based on the heat-pulse and capacitance methods. The capacitance method relates the volumetric water content with the capacitance change (dielectric properties) of a probe, inserted in the soil. Several tests were performed for different type of soils and water contents. These results are compared with the measurements achieved using the conventional thermogravimetric method.