ROMJIST Volume 24, No. 2, 2021, pp. 222-232, Paper no. 690/2021
Matei SERBANESCU, Vlad-Mihai PLACINTA, Florin NASTASE, Gheorghe PRISTAVU, Octavian BUIU, Gheorghe BREZEANU, Bogdan SERBAN A Standalone System for Resistive Smart Sensors Based on a Wheatstone Quarter-Bridge
ABSTRACT: This paper presents the architecture of a resistive smart-sensor based on a Wheatstone quarter-bridge. The overall system also comprises a signal-conditioning circuit and a microcontroller. The intended sensing element is a small-variation chemo-resistive sensor. Its resistance gradient is converted by the conditioning circuit into a signal with variable duty-cycle. The proposed architecture is theoretically analyzed and validated by both simulations and measurements on a prototype, implemented with discrete and low-cost components. The output signal exhibits a maximum of 1.8% relative error, for a sensing element value variation of 10 Ω. Sensing linearity is assessed via R2 at up to 0.9995, while sensitivity reaches 57.71 μs/Ω.KEYWORDS: Resistive sensor, quarter-bridge, signal-conditioning circuit, microcontroller, duty-cycleRead full text (pdf)