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Proceedings Paper

1.5mm precision liquid level measurement using impedance spectroscopy
Author(s): Bhuwan Kashyap; Charles Sestok; Anand Dabak; Srinath Ramaswamy; Ratnesh Kumar
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Paper Abstract

An impedance measurement based level sensor is proposed using a co-axial probe for sensing liquid level in a container. The co-axial sensing probe is made with a hollow stainless steel outer conductor enclosing an insulated inner conductor. The impedance of the co-axial probe varies with the water level in a nonlinear fashion. The supporting electronics was developed using MSP 432 microcontroller unit (MCU) platform from Texas Instruments (TI) and a newly designed Impedance Analyzer-Analog Front End (IA-AFE) developed at TI. An inverter amplifier based circuit was implemented within the IA-AFE for impedance measurement. Discrete Fourier Transform (DFT) is calculated on the MCU platform from the sampled input and output square wave voltages of the IA-AFE. The proposed sensor shows a maximum error within ±1.5 mm, for the probe of length 40 cm. The proposed system offers an accurate and economical liquid level measurement platform outperforming the state-of-art level sensors to the best of our knowledge.

Paper Details

Date Published: 3 May 2018
PDF: 8 pages
Proc. SPIE 10643, Autonomous Systems: Sensors, Vehicles, Security, and the Internet of Everything, 106430Y (3 May 2018); doi: 10.1117/12.2305014
Show Author Affiliations
Bhuwan Kashyap, Iowa State Univ. (United States)
Charles Sestok, Texas Instruments Inc. (United States)
Anand Dabak, Texas Instruments Inc. (United States)
Srinath Ramaswamy, Texas Instruments Inc. (United States)
Ratnesh Kumar, Iowa State Univ. (United States)

Published in SPIE Proceedings Vol. 10643:
Autonomous Systems: Sensors, Vehicles, Security, and the Internet of Everything
Michael C. Dudzik; Jennifer C. Ricklin, Editor(s)

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