Direct inductive sensor-to-microcontroller interface circuit

Kokolanski, Živko; Barnils, José Jordana; Gasulla, Manel; Dimčev, Vladimir; Reverter, Ferran

doi:10.1016/j.sna.2015.01.017

Cited by 48 publications

(34 citation statements)

References 20 publications

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“…EADING sensors through a time-to-digital converter (TDC) instead of an analog-to-digital converter (ADC) has several advantages, for instance: (1) in microcontroller-based designs, the current consumption of an embedded TDC is clearly lower than that of an ADC; and (2) in integrated designs, the layout area occupied by a TDC is one or two orders of magnitude smaller than that required by an ADC. Accordingly, timer-based circuits for resistive [1]- [3], capacitive [4], [5], inductive [6], [7], and voltage-output [8], [9] sensors have been extensively analyzed and developed in the last decade. For the case of voltage-output sensors, usually it is assumed that the sensor provides a quasi-static analog output voltage [8], [9].…”

Section: Introductionmentioning

confidence: 99%

Rail-to-Rail Timer-Based Demodulator for AM Sensor Signals

Reverter

2019

IEEE Trans. Instrum. Meas.

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This paper proposes a novel timer-based demodulator for low-frequency amplitude-modulated (AM) sensor signals with a rail-to-rail operating range. The demodulator extracts the amplitude of the AM signal by measuring the period of a reference signal that is altered by the AM signal itself, as already suggested in a previous paper. The rail-to-rail operation, which is the main contribution of the novel circuit, is achieved by simply but cleverly incorporating a multiplexer that enables the comparison between the two signals (reference and AM) just at the beginning and at the end of the period measurement. This new topology offers an operating range that is up to more than four times wider than that reported in the literature. The input-output characteristic in such a wider operating range is not linear, but it can be accurately modelled by a second-degree polynomial.

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Section: Introductionmentioning

confidence: 99%

Rail-to-Rail Timer-Based Demodulator for AM Sensor Signals

Reverter

2019

IEEE Trans. Instrum. Meas.

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“…As for the read-out electronic circuit, it is proposed to read both large- and small-signal variations of the FSR applying the concept of direct interface circuit (DIC) [12], where the sensor is directly connected to a low-cost microcontroller unit (MCU) without using intermediate analogue electronics either an analogue-to-digital converter (ADC). These MCU-based circuits have been extensively analyzed and proved for resistive [13,14,15], capacitive [16,17,18] and inductive [19,20] sensors with different topologies, but not for resistive sensors undergoing both large- and small-signal variations, as we have in the application of interest here. DICs have also been suggested for sensors providing a quasi-static analogue output voltage [21,22] and as a versatile interface circuit for the measurement of different types of sensor [23].…”

Section: Introductionmentioning

confidence: 99%

Seat Occupancy Detection Based on a Low-Power Microcontroller and a Single FSR

Sifuentes

González-Landaeta

Cota-Ruiz

et al. 2019

Sensors

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This paper proposes a microcontroller-based measurement system to detect and confirm the presence of a subject in a chair. The system relies on a single Force Sensing Resistor (FSR), which is arranged in the seat of the chair, that undergoes a sudden resistance change when a subject/object is seated/placed over the chair. In order to distinguish between a subject and an inanimate object, the system also monitors small-signal variations of the FSR resistance caused by respiration. These resistance variations are then directly measured by a low-cost general-purpose microcontroller unit (MCU) without using either an analogue processing stage or an analogue-to-digital converter. Two versions of such a MCU-based circuit are presented: one to prove the concept of the measurement, and another with a smart wake-up (generated by the sudden resistance change) intended to reduce the energy consumption. The feasibility of the proposed measurement system is experimentally demonstrated with subjects of different weight sitting at different postures, and also with objects of different weight. The MCU-based circuit with a smart wake-up shows a standby current consumption of 800 nA, and requires an energy of 125 µJ to carry out the measurement after the wake-up.

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“…Both large-and small-signal variations of the FSR are then directly measured by a low-cost microcontroller using the concept of direct interface circuit (DIC) [10]. These have been extensively analyzed for resistive [11][12][13][14], capacitive [15] and inductive [16] sensors with different topologies, but not for resistive sensors undergoing both large-and small-signal variations.…”

Section: Introductionmentioning

confidence: 99%

Microcontroller-Based Seat Occupancy Detection and Classification

et al. 2018

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This paper presents a microcontroller-based measurement system to detect and confirm the presence of a subject in a chair. The system relies on a single Force Sensing Resistor (FSR), which may be arranged in the seat or backrest of the chair, that undergoes a sudden resistance change when a subject/object is seated/placed over the chair. In order to distinguish between a subject and an inanimate object, the system also monitors small-signal variations of the FSR resistance caused by respiration. These resistance variations are then directly measured by a low-cost general-purpose microcontroller without using either an analogue processing stage or an analogue-to-digital converter, thus resulting in a low-cost, low-power, compact design solution.

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Direct inductive sensor-to-microcontroller interface circuit

Cited by 48 publications

References 20 publications

Rail-to-Rail Timer-Based Demodulator for AM Sensor Signals

Rail-to-Rail Timer-Based Demodulator for AM Sensor Signals

Seat Occupancy Detection Based on a Low-Power Microcontroller and a Single FSR

Microcontroller-Based Seat Occupancy Detection and Classification

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