1,422 research outputs found
Measuring dynamic signals with direct sensor-to-microcontroller interfaces applied to a magnetoresistive sensor
This paper evaluates the performance of direct interface circuits (DIC), where the sensor is directly connected to a microcontroller, when a resistive sensor subjected to dynamic changes is measured. The theoretical analysis provides guidelines for the selection of the components taking into account both the desired resolution and the bandwidth of the input signal. Such an analysis reveals that there is a trade-off between the sampling frequency and the resolution of the measurement, and this depends on the selected value of the capacitor that forms the RC circuit together with the sensor resistance. This performance is then experimentally proved with a DIC measuring a magnetoresistive sensor exposed to a magnetic field of different frequencies, amplitudes, and waveforms. A sinusoidal magnetic field up to 1 kHz can be monitored with a resolution of eight bits and a sampling frequency of around 10 kSa/s. If a higher resolution is desired, the sampling frequency has to be lower, thus limiting the bandwidth of the dynamic signal under measurement. The DIC is also applied to measure an electrocardiogram-type signal and its QRS complex is well identified, which enables the estimation, for instance, of the heart rate.Postprint (published version
Configurable 3D-integrated focal-plane sensor-processor array architecture
A mixed-signal Cellular Visual Microprocessor architecture with digital processors is
described. An ASIC implementation is also demonstrated. The architecture is composed of a
regular sensor readout circuit array, prepared for 3D face-to-face type integration, and one or
several cascaded array of mainly identical (SIMD) processing elements. The individual array
elements derived from the same general HDL description and could be of different in size, aspect
ratio, and computing resources
WiForceSticker: Batteryless, Thin Sticker-like Flexible Force Sensor
Any two objects in contact with each other exert a force that could be simply
due to gravity or mechanical contact, such as a robotic arm gripping an object
or even the contact between two bones at our knee joints. The ability to
naturally measure and monitor these contact forces allows a plethora of
applications from warehouse management (detect faulty packages based on
weights) to robotics (making a robotic arms' grip as sensitive as human skin)
and healthcare (knee-implants). It is challenging to design a ubiquitous force
sensor that can be used naturally for all these applications. First, the sensor
should be small enough to fit in narrow spaces. Next, we don't want to lay
cumbersome cables to read the force values from the sensors. Finally, we need
to have a battery-free design to meet the in-vivo applications. We develop
WiForceSticker, a wireless, battery-free, sticker-like force sensor that can be
ubiquitously deployed on any surface, such as all warehouse packages, robotic
arms, and knee joints. WiForceSticker first designs a tiny
~mm~~~mm~~~mm capacitative sensor design equipped
with a ~mm~~~mm antenna designed on a flexible PCB substrate.
Secondly, it introduces a new mechanism to transduce the force information on
ambient RF radiations that can be read by a remotely located reader wirelessly
without requiring any battery or active components at the force sensor, by
interfacing the sensors with COTS RFID systems. The sensor can detect forces in
the range of -~N with sensing accuracy of ~N across multiple
testing environments and evaluated with over varying force level
presses on the sensor. We also showcase two application case studies with our
designed sensors, weighing warehouse packages and sensing forces applied by
bone joints
Low-power direct resistive sensor-to-microcontroller interfaces
â© © 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.âThis paper analyzes the energy consumption of
direct interface circuits where the data conversion of a resistive
sensor is performed by a direct connection to a set of digital ports
of a microcontroller (”C). The causes of energy consumption
as well as their relation to the measurement specifications in
terms of uncertainty are analyzed. This analysis yields a tradeoff
between energy consumption and measurement uncertainty,
which sets a design procedure focused on achieving the lowest
energy consumption for a given uncertainty and a measuring
range. Together with this analysis, a novel experimental setup is
proposed that allows one to measure the ”Câs timer quantization
uncertainty. An application example is shown where the design
procedure is applied. The experimental results fairly fit the
theoretical analysis, yielding only 5 ”J to achieve nine effective
number of bits (ENOB) in a measuring range from 1 to 1.38 k.
With the same ENOB, the energy is reduced to 1.9 ”J when the
measurement limits are changed to 100 and 138 k.Peer ReviewedPostprint (published version
Uncalibrated operational amplifier-based sensor interface for capacitive/resistive sensor applications
In this paper, a new configuration of operational amplifier -based square-wave oscillator is proposed. The circuit performs an impedance-to-period (ZâT) conversion that, instead of a voltage integration typically performed by other solutions presented in the literature, is based on a voltage differentiation. This solution is suitable as first analogue uncalibrated front-end for capacitive and resistive (e.g. relative humidity and gas) sensors, working also, in the case of capacitive devices, for wide variation ranges (up to six capacitive variation decades). Moreover, through the setting of passive components, its sensitivity can be easily regulated. Experimental measurements, conducted on a prototype printed circuit board, with sample passive components and using the commercial capacitive humidity sensor Honeywell HCH-1000, have shown good linearity and accuracy in the estimation of capacitances, having a baseline or reaching a value ranging in a wide interval [picofaradsâmicrofarads], as well as, with a lower accuracy, in the evaluation of more reduced variations of resistances, ranging from kiloohms to megaohms, also when compared with other solutions presented in the literature
Floating-Gate Design and Linearization for Reconfigurable Analog Signal Processing
Analog and mixed-signal integrated circuits have found a place in modern electronics design as a viable alternative to digital pre-processing. With metrics that boast high accuracy and low power consumption, analog pre-processing has opened the door to low-power state-monitoring systems when it is utilized in place of a power-hungry digital signal-processing stage. However, the complicated design process required by analog and mixed-signal systems has been a barrier to broader applications. The implementation of floating-gate transistors has begun to pave the way for a more reasonable approach to analog design. Floating-gate technology has widespread use in the digital domain. Analog and mixed-signal use of floating-gate transistors has only become a rising field of study in recent years. Analog floating gates allow for low-power implementation of mixed-signal systems, such as the field-programmable analog array, while simultaneously opening the door to complex signal-processing techniques. The field-programmable analog array, which leverages floating-gate technologies, is demonstrated as a reliable replacement to signal-processing tasks previously only solved by custom design. Living in an analog world demands the constant use and refinement of analog signal processing for the purpose of interfacing with digital systems. This work offers a comprehensive look at utilizing floating-gate transistors as the core element for analog signal-processing tasks. This work demonstrates the floating gate\u27s merit in large reconfigurable array-driven systems and in smaller-scale implementations, such as linearization techniques for oscillators and analog-to-digital converters. A study on analog floating-gate reliability is complemented with a temperature compensation scheme for implementing these systems in ever-changing, realistic environments
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