A High Accuracy Measurement Circuit for Soil Moisture Detection

Authors: Sheroz Khan, A. H. M. Zahirul Alam, Othman O. Khalifa, Mohd Rafiqul Islam, Zuraidah Zainudin, Muzna S. Khan, Nurul Iman Muhamad Pauzi

Abstract:

The study of soil for agriculture purposes has remained the main focus of research since the beginning of civilization as humans- food related requirements remained closely linked with the soil. The study of soil has generated an interest among the researchers for very similar other reasons including transmission, reflection and refraction of signals for deploying wireless underground sensor networks or for the monitoring of objects on (or in ) soil in the form of better understanding of soil electromagnetic characteristics properties. The moisture content has been very instrumental in such studies as it decides on the resistance of the soil, and hence the attenuation on signals traveling through soil or the attenuation the signals may suffer upon their impact on soil. This work is related testing and characterizing a measurement circuit meant for the detection of moisture level content in soil.

Keywords: Analog–digital Conversion, Bridge Circuits, Intelligent sensors, Pulse Time Modulation, Relaxation Oscillator

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1079990

References:

[1] Peter Arzberger, University of California at San Diego , Sensors for Environmental Observatories, Report of the NSF-Sponsored Workshop December 2004
[2] R.A Carley1 & E. Heggy, "Characterization of the Density Dependent Dielectric Properties of Mars-Like Soils: Implications For Mars Radar Studies," University of Cambridge, United Kingdom, Lunar and Planetary Science XXXVII (2006), Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston
[3] Jatupum Jenwatanavet and Joel T. Johnson, Member, IEEE, "An Analytical Model for Studies of Soil Modification Effects on Ground Penetrating Radar" , IEEE Trans. on Antennas and Propagation, vol. 49, no. 6, June 2001
[4] K. Mochizuki and K. Watanabe, "A high-resolution, linear resistance-tofrequency converter," IEEE Trans. Instrum. Meas., vol. 45, pp. 761-764, 1996.
[5] Vittorio Ferrari, Carla Ghidini, Daniele Marioli, and Andrea Taroni, "Oscillator-Based Signal Conditioning with Improved Linearity for Resistive Sensors," IEEE Transactions on Instrumentation And Measurement, Vol. 47, No. 1, February 1998
[6] S. Kaliyugavaradan, "A Linear Resistance-To-Time Converter with High Resolution," IEEE Trans. Instrum. Meas., Vol. 49, no. 1, February 2000.
[7] Kouji Mochizuki, Kenzo Watanabe, Fellow, IEEE, Takashi Masuda, and Motoyasu Katsura, "A Relaxation-Oscillator-Based Interface for High- Accuracy Ratio-metric Signal Processing of Differential-Capacitance Transducers, "IEEE Trans. on Instrum., vol. 47, no. 1, February1998
[8] Satish Chnadra Bera, Jayanta Kumar Ray, and Subrata Chattopadhyay, "A Low-Cost Noncontact Capacitance-Type Level Transducer for a Conducting Liquid," IEEE Trans. Instrum. Meas. vol. 55, no. 3, pp. 778- 786, June 2006.