1.5mm precision liquid level measurement using impedance spectroscopy

Bhuwan Kashyap; Charles Sestok; Anand Dabak; Srinath Ramaswamy; Ratnesh Kumar

doi:10.1117/12.2305014

3 May 2018 1.5mm precision liquid level measurement using impedance spectroscopy

Bhuwan Kashyap, Charles Sestok, Anand Dabak, Srinath Ramaswamy, Ratnesh Kumar

Proceedings Volume 10643, Autonomous Systems: Sensors, Vehicles, Security, and the Internet of Everything; 106430Y (2018) https://doi.org/10.1117/12.2305014
Event: SPIE Defense + Security, 2018, Orlando, FL, United States

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.

Citation Download Citation

Bhuwan Kashyap, Charles Sestok, Anand Dabak, Srinath Ramaswamy, and Ratnesh Kumar "1.5mm precision liquid level measurement using impedance spectroscopy", Proc. SPIE 10643, Autonomous Systems: Sensors, Vehicles, Security, and the Internet of Everything, 106430Y (3 May 2018); https://doi.org/10.1117/12.2305014

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