Rahmondia Nanda Setiadi

Low cost soil sensor based on impedance spectroscopy for in-situ measurement

Soil moisture is a significant element in the water cycle, on an agricultural and in land interaction. In crop production, soil plays a key role as a physical support and a reservoir of water and nutrients. Decisions for optimized input rates of water are largely based on physical, chemical, and biological properties of soils. The aim of this work is to develop a low cost soil moisture sensor (SMS) based on impedance spectroscopy by means of magnitude ratio and phase difference detection method. Using impedance spectroscopy, more information can be delivered from real and imaginary part of the complex permittivity for several frequencies at the same moisture value. For this purpose, a probe has been designed which uses a simplified impedance measuring system to determine soil water content. The circuit sweeps at pre-programmed frequencies from 10 KHz to 10MHz with 10 mV AC amplitude. A local inceptisol soil of East Sumatra was especially selected for this investigation because measurements of soil moisture in peat swamp area were generally reported as challenging to analyze. Samples at defined soil moisture of 2%, 8%, 15% measured using commercial soil sensor Lutron PMS-714, was characterized. A model has been developed in order to correct the frequency influence upon the measurement. The results obtained by the sensor show good results with an overall mean error of 0.21% in impedance.Soil moisture is a significant element in the water cycle, on an agricultural and in land interaction. In crop production, soil plays a key role as a physical support and a reservoir of water and nutrients. Decisions for optimized input rates of water are largely based on physical, chemical, and biological properties of soils. The aim of this work is to develop a low cost soil moisture sensor (SMS) based on impedance spectroscopy by means of magnitude ratio and phase difference detection method. Using impedance spectroscopy, more information can be delivered from real and imaginary part of the complex permittivity for several frequencies at the same moisture value. For this purpose, a probe has been designed which uses a simplified impedance measuring system to determine soil water content. The circuit sweeps at pre-programmed frequencies from 10 KHz to 10MHz with 10 mV AC amplitude. A local inceptisol soil of East Sumatra was especially selected for this investigation because measurements of soil moistur...

Self-Powered Wireless Sensor for Forest-Fire Detection in Sumatera with Various Environmental Energy Source

This paper presents a fire sensor module which is powered by harvested energy from the surrounding environment. The complete system consists of a transmitter module that sources energy from a mini generator energized by wind and thermal energy. The presented green energy poweredfire sensor is environmentally friendly and can be mass produced at a very low cost. A prototype of the forest-fire sensor consisted of transmitter and receiver module of STM110 EnOcean Firma has been constructed. The fire-sensor module detects the presence of fire in the vicinity using an NTC (negative temperature coefficient) temperature sensor. The thermistor is mounted on the exterior of the prototype (casing) and its switch-temperature is set between 90°C and 95°C. A rapid rise in the temperature above the set switch-temperature causes a rapid change in the sensor resistance, indicating the presence of a nearby fire. In response, the sensor would send a telegram to the central station (receiver module).