Hidalgo-López, José A.Oballe-Peinado, ÓscarCastellanos-Ramos, JuliánSánchez-Durán, José A.2022-07-112022-07-112021-02-22Hidalgo-López JA, Oballe-Peinado Ó, Castellanos-Ramos J, Sánchez-Durán JA. Two-Capacitor Direct Interface Circuit for Resistive Sensor Measurements. Sensors. 2021 Feb 22;21(4):1524http://hdl.handle.net/10668/3771Direct interface circuits (DICs) avoid the need for signal conditioning circuits and analog-to-digital converters (ADCs) to obtain digital measurements of resistive sensors using only a few passive elements. However, such simple hardware can lead to quantization errors when measuring small resistance values as well as high measurement times and uncertainties for high resistances. Different solutions to some of these problems have been presented in the literature over recent years, although the increased uncertainty in measurements at higher resistance values is a problem that has remained unaddressed. This article presents an economical hardware solution that only requires an extra capacitor to reduce this problem. The circuit is implemented with a field-programmable gate array (FPGA) as a programmable digital device. The new proposal significantly reduces the uncertainty in the time measurements. As a result, the high resistance errors decreased by up to 90%. The circuit requires three capacitor discharge cycles, as is needed in a classic DIC. Therefore, the time to estimate resistance increases slightly, between 2.7% and 4.6%.enAtribución 4.0 Internacionalhttp://creativecommons.org/licenses/by/4.0/Direct interface circuitsInterface sensorResistive sensorTime-based measurementCalibration methodsUncertaintyIncertidumbreRedes neurales de la computaciónComputadoras de manoMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Therapeutics::Patient Care::Hospitalization::Patient DischargeMedical Subject Headings::Phenomena and Processes::Mathematical Concepts::Probability::UncertaintyMedical Subject Headings::Organisms::Eukaryota::Animals::Chordata::Vertebrates::Mammals::Primates::Haplorhini::Catarrhini::Hominidae::HumansMedical Subject Headings::Phenomena and Processes::Mathematical Concepts::Neural Networks (Computer)Medical Subject Headings::Phenomena and Processes::Mathematical Concepts::AlgorithmsMedical Subject Headings::Information Science::Information Science::Computing Methodologies::Computer Systems::Computers::Microcomputers::Computers, HandheldMedical Subject Headings::Information Science::Information Science::Computing Methodologies::Computer Systems::Computers::Computers, Hybrid::Analog-Digital ConversionMedical Subject Headings::Information Science::Information Science::Computing Methodologies::Computer Systems::ComputersMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Investigative Techniques::Calibrationresearch article33671720Acceso abierto10.3390/s210415241424-8220PMC7926314