Type Of Pressure Sensor Research Articles

Cellulose/Single‐Walled Carbon Nanotube‐Based Pressure‐Sensing Thin Film Transistor with Channel Conductivity Modulation

Field‐effect transistor (FET)‐type pressure sensor offers excellent amplification and signal conversion functionality as a switching device, and it has the capability to integrate tactile sensors by constructing active‐matrix arrays with low crosstalk. However, conventional FET‐type pressure sensors either have a complex device layout with additional components, such as pressure‐sensitive elastomer, attached to the source/drain electrodes, or the method of modulating the gate dielectric can lead to dielectric breakdown and device failure. Additionally, the deformation of the elastomer limits response speed and causes differences in early and late response characteristics. In this article, a facile structure pressure‐sensing thin film transistor (TFT) that modulates the channel conductivity by cellulose/single‐wall carbon nanotube (SWCNT) composite is reported, ensuring a simple layout without damaging the device. The fabricated cellulose/SWCNT‐based pressure‐sensing TFT exhibits a change in the on/off current ratio from 2.75 × 103 to 2.0 × 104 in response to pressure with high linearity (R2 = 0.9935) and maintains durable performance over 2000 loading‐unloading cycles. Additionally, the sensor shows a fast response time of less than 8 ms. A practical concept of sensing circuits is demonstrated based on pressure‐sensing TFTs for integration into display driving circuits, enabling accurate pressure sensing using only the signal to drive the display.

Capacitive Flexible Pressure Sensors and Their Application

Because of their importance in obtaining information from people and automatic equipment, flexible pressure sensors (FPS) have been widely used in diverse fields such as electronic skin, soft robots, consumer electronics, health monitoring, and human-computer interaction. Among all kinds of soft pressure sensors, capacitance pressure sensor is characterized by its simple construction, low cost, and stable performance. Although this type of pressure sensor is easily made, it is still a hotspot to increase the sensitivity and extend the efficiency of the system. This paper reviews the related research on flexible capacitive pressure sensors, including working mechanism, capacitor structures, methods to improve the performance of capacitive sensors, and applications. Finally, a comparison is made between the efficient approaches for achieving high-sensitivity, and the developing tendency of flexible capacitance sensor is predicted.The purpose of this thesis is to offer some useful information for the study of highly sensitive and highly sensitive materials for manufacturing flexible capacitive sensors.

Review and Analysis of the Characteristics of IoT Sensors

Internet of things (IoT) is the concept of data transmission network between physical objects ("things"), equipped with built-in tools and technologies for interaction with each other or with the environment. The work is devoted to the inspection and analysis of sensors, how the IoT systems are associated with environmental objects. IOT uses a wide class of measurement tools, from elementary sensors (eg, temperature, pressure, light), consumption metering devices (such as intellectual meters) to complex integrated measuring systems. The parameters of 30 types of sensors for IoT are given, 2 of them of the type of temperature and humidity sensors, 2 type of pressure sensors, 13 sensors that measure the flow and amount of gas or liquid, 2 type of accelerometers, 10 approach and movement sensors and 1 noise sensor. Among them are 4 sensors for wireless sensory networks (WSM), a single-time medical sensor for internal blood pressure measurement, calorimetric, vortex and electromagnetic flow sensors and gas or fluid, accelerometer, and memes of memes, and e-memometers, and electromagnetic measurement motion, a device of measuring noise level in the range of sound vibrations. For some sensors, there are no metrological characteristics at all, at best there is only a range of measurements and resolution. The resolution ranges from 8 bits to 16 bits with a signal sampling rate from 0.5 Hz to 48 kHz. There is even a LDC1612 digital induction chip with 28 bits. WSM sensors are designed to work with DigiMesh, LoraWan and Arduino, Raspberry. Many sensors use outdated RS 232, RS 432, I2C. Keywords: internet of things, network, review, analysis, sensors, objects, metrology.

Self-powered flexible battery pressure sensor based on gelatin

The application of pressure sensors with excellent performance in medicine, flexible electronic skin, artificial intelligence, etc. has received much attention. However, most of the current pressure sensors have either the need for an external power supply or the difficulty of accurately measuring the static continuous signal, which greatly limit the development of sensor technology. We report a gelatin-based battery type pressure sensor in which a gelatin composite hydrogel membrane is introduced as the sensing layer in a zinc ion battery, and the zinc battery itself is designed as a pressure sensor. An isolation layer is also added to the solid zinc ion battery to realize the function of converting mechanical pressure signals to electrical signals more accurately. The gelatin battery pressure sensor designed in this paper has the advantages of being self-powered, high sensitivity (37.9 mV/kPa), wide pressure detection range (up to 524 kPa), good stability, short response/recovery time, and high biological applicability. In addition, the battery-type pressure sensor has the ability to detect static signals and maintain good performance under 10,000 s of external mechanical pressure. The design of this battery-based pressure sensor provides a new strategy for the development of self-powered pressure sensors and flexible electronic skin devices.

Methods to improve the sensitivity of micro-capacitive pressure sensors

Novel micro pressure sensors require high sensitivity, anti-interference, reliability and durability. However, due to some problems in mold making, digital signal process circuits and so on, it is difficult for the existing micro-capacitive pressure sensors to make a breakthrough in sensitivity. Firstly, this paper briefly introduces the micro-pressure capacitive sensors principle and the technical difficulties they face. After that, several schemes are listed, including digital signal process circuits, laser-induced graphene, etc. The feasibility and practicability of these methods to improve the sensitivity of micro-capacitive pressure sensors are compared and demonstrated. The following types of pressure sensors, including PDMS-based and MEMS-based pressure sensors, have their specific functions and shortcomings. The paper aims to provide some references for further research in this field, and to give some useful opinions on the practical application of micro-capacitive pressure sensors in IoT and other fields.

3D Resin-coated pressure sensor response for bite force assessment: A pilot study.

Occlusal splints with sensors help in the bruxism diagnosis and monitoring, by recording the patient's bite force. The aim of this study was to evaluate the accuracy of a pressure sensor when it is covered with different thicknesses of a 3D printing resin (Anycubic 405nm Translucent Green UV Resin, Anycubic, UK). In this preliminary study, the evaluated sensor (FlexiForce A201 Sensor, Tekscan) was firstly calibrated without any type of cover material, and later tested with 3D printing resin with different thicknesses (1 mm, 1.15 mm, 1.4 mm and 1.6 mm). The load tests were performed by a force tester (MultiTest 2.5 dV, Mecmesin). When the pressure sensor was covered with resin of 1mm and 1.6 mm thick specimens, a higher difference was found between the applied load and the corresponding sensor reading. It was concluded that it is possible to use this type of pressure sensor and that it showed better accuracy with the 1.15 mm and 1.4 mm 3D printing resin covering.

Design and Implementation of Vertically Integrated Deformable Hermetic Chambers for the Sensitivity Enhancement of CMOS-MEMS Capacitive Pressure Sensor

This study presents the design and implementation of a capacitive type pressure sensor with vertically integrated deformable hermetic chambers based on the standard commercial processes (the Taiwan Semiconductor Manufacturing Company (TSMC) 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> 1P6M complementary metal-oxide-semiconductor (CMOS) process) and the in-house post CMOS processes. The proposed pressure sensor features the realization of two vertically integrated hermetic chambers consisting of two deformable diaphragms with embedded sensing electrodes and one diaphragm with reference electrodes. Thus, the sensitivity of the pressure sensor can be improved for near twofold within the same footprint. Moreover, the stepped structure is designed to reduce the stiffness of the deformable diaphragms to further enhance the sensitivity of the proposed sensor. The feasibility of the proposed design has been evaluated through both finite element method (FEM) simulations and experiments. Measurement results indicate, as compared with the reference design with only one deformable hermetic chamber, the proposed pressure sensor with vertically integrated deformable hermetic chambers has a near twofold enhancement in sensitivity within the pressure range of 20–120 kPa. Additionally, the proposed design with the deformable stepped-diaphragm can enhance the sensitivity by about 5.1-fold within the same pressure range.

Analyzing the effect of existing bubbles in the interface liquid on the dynamic response of the strain-gauge type pressure sensor

This paper studies one of the major failures, that may occur in macro-scale strain gauge pressure sensors as well as micro-scale ones. The leakage in the interface fluid chamber of the sensor causes the air to be trapped especially in the form of bubbles in the interface liquid near the boundaries. In this work, mathematical modeling of a strain gauge pressure sensor in the presence of the trapped micro-scale bubbles in the interface liquid is presented. The governing equations of displacement of the membrane and sensing plate coupled with the nonlinear dynamic equation of bubbles are solved simultaneously utilizing the Galerkin weighted residual method. The transient response of the sensor in the presence of bubbles is investigated considering different types of applied dynamic pressure as step, single pulse, repetitive pulse, and harmonic. Results indicate that when a higher percentage of the interface oil is filled with bubbles, the maximum overshoot in the response of the sensor reduces, while, the peak time, rise time, and also settling time in the response of the sensor increases. A delay is observed in the time-domain response of the sensor due to the reduction of speed of transferring data from the membrane to the sensing plate caused by the bubbles in the interface liquid.

Review of Minimally Invasive and Invasive MEMS Devices for Biomedical Diagnostic Applications: Design Aspects

The demand of MEMS biosensors in biomedical applications is enormous which has driven the review of such devices. Various biosensors that are available in the market and under research are inadequate in providing pickup and amplification of the bio-signals for diagnosis and treatment purposes. In this review, various biosensors implemented and deployed through invasive and non-invasive techniques are reviewed to determine their adequacy in diagnosis and treatment. A MEMS device also has been specifically designed for the pickup of intra-ocular pressure for early diagnosis of glaucoma. Piezoresistive type pressure sensor is designed to provide better accuracy in the pickup of such biomedical signals. The designed device which is analyzed using the COMSOL Multiphysics provided better sensitivity of around 26.6mV/V/MPa and a non-linearity of &lt; 1%, which will promote better diagnosis.

Arrayed porous polydimethylsiloxane/barium titanate microstructures for high-sensitivity flexible capacitive pressure sensors

Flexible and wearable devices have been gaining attention in recent years. Compared with other types of pressure sensors, capacitive pressure sensors provide more advantages including simple structure, high stability and reliability, and lower power consumption. This study proposed the flexible capacitive pressure sensors with a double dielectric layer of a porous micro-pillar composite structure of polydimethylsiloxane (PDMS) as the dielectric layer. To further enhance the sensitivity, barium titanate (BT) particles were mixed in the PDMS due to their high relative permittivity. Moreover, finite element analysis (FEA) was utilized to simulate the displacement of the dielectric layer under applying external pressure. The FEA simulation results showed that the proposed structure of the dielectric layer could effectively enhance the sensitivity of the flexible capacitive pressure sensor. Furthermore, the flexible capacitive pressure sensor demonstrates a superb performance with a high sensitivity of 7.847 kPa−1, a low detection limit of 0.21 Pa, and a fast response and release time of 20 ms and 25 ms. The developed sensors have an excellent sensing capability and can be applied widely for monitoring of heartbeat, sensing of the robot arm, measuring of floor height, detecting of weights of objects, and real-time monitoring of healthcare.

Investigating Static and Dynamic Behavior of the Strain Gauge Type Pressure Sensor in Exposure to Thermal Stresses

Investigating Static and Dynamic Behavior of the Strain Gauge Type Pressure Sensor in Exposure to Thermal Stresses

Investigation of Interface Oil Insufficiency in a Strain Gauge Type Pressure Sensor

Strain gauge type pressure sensors are widely used in different branches of industry to measure pressure from very low to very high (1400 Mpa) values. This article investigates a strain gauge type pressure sensor that uses silicon oil within its housing to transmit working pressure from the external environment to a sensing plate. An important failure mode arises from loss/leakage of the silicon oil, whereby a portion of the internal volume is replaced by gas, usually air. Coupled nonlinear governing equations have been derived and solved in both static and dynamical states to describe the behavior of the external membrane, the interface oil including pockets of gas, and the sensing plate. Nonlinear behavior arises from the plate and membrane midplane stretching, and of course the behavior of the gas. The resulting model describes how oil loss affects the sensor performance and changes the sensor output and pressure measurable range.

Synthesis of NiS2 nanomaterial as wide range pressure sensor

With the vigorous development of industry and information technology, people's requirements for sensors are becoming more and more diversified and universal. It is still a challenge to find a new type of pressure sensor with low cost, simple preparation, wider pressure test range, and higher sensitivity. Hereby, we report a novel flexible pressure sensor with a wide pressure detection range and robust mechanical properties, taking advantage of transition metal sulfide NiS2, adsorbed in melamine sponge as the active substance. The flexible sensor deforms under pressure with a internal microstructure change and a corresponding conductivity ramping. The addition of elastic polyvinylidene fluoride after curing improves the impact resistance and enables higher stability. Experiments show that the resistance pressure sensor responds within a wide range of 50 kPa with a high sensitivity of below 0.0345 kPa−1 and a fast response time of 0.64 s. Its excellent performance makes the sensor promising for wearable electronics and health monitoring devices.

An improved capacitance pressure sensor with a novel electrode design

Pressure sensors are one of the most widely used sensors in many process loops. It is said that around two-thirds of the process loop contains at least a pressure sensor, thus making it very important to have a pressure sensor with higher accuracy, sensitivity, etc. The capacitance type pressure sensor is one of the variants of pressure sensors based on the principle of change in capacitance for change in input pressure. The objective of the proposed work is to design a novel pressure sensor with improved sensitivity and accuracy as compared to a conventional diaphragm-based capacitance pressure sensor. The shape and pattern of electrodes used in the capacitance pressure sensor are varied without affecting the overall dimensions. The obtained capacitance is converted to voltage with the help of a signal conditioning circuit, which is further linearized using regression algorithms. From the results obtained it is seen that the proposed sensor has an improvement in sensitivity by a factor of 79 over the conventional diaphragm pressure sensor of similar dimension and composition. The proposed method on implementation in real-life resulted in a root mean square percentage error of 0.46%.

Self-powered direct-current type pressure sensor by polypyrrole/metal Schottky junction

Pressure sensors are widely used in intelligent systems. With the extension of application conditions, pressure sensors with energy-sustainable, large-area, and high-density are urgently needed to be designed. In this article, we proposed a polymer/metal Schottky junction structure to achieve flexible self-powered pressure sensors (SPSs), in which the Schottky junction has the capability of converting mechanical energy to direct current (DC) without external rectifier. The constructed pressure sensor holds a sandwich structure simply made up of an Au layer, a p-type semiconductor polypyrrole layer, and an Al layer. Test results show that this pressure sensor has the ability of self-power supply with output 0.79 V DC voltage which is almost independent of the area of pressure sensor, and has an outstanding output power density of 33.4 μW cm−2, a high response speed with 33 ms, and a good sensitivity of 0.0143 V kPa−1 in the pressure range of 0–60 kPa. Furthermore, it can sense both the dynamic and static forces. This work provides a simple but efficient method to develop SPSs, which show potentials in electronic skin with tactile function and artificial intelligence.

Pressure exerted on formwork by self-compacting concrete at early ages: A review

Self-Compacting Concrete (SCC) is a flowable concrete that exerts high pressure on formwork. SCC is the most commonly used concrete worldwide for construction applications due to its cost-effectiveness. The high flow of SCC reduces both the number of workers and the casting time required. It also eliminates vibration and removes noise pollution. This study is a review of previous investigations into the pressure exerted by fresh-state SCC on formwork. The paper discussed various factors that affect lateral pressure on formwork. These factors are included theoretical predictions, the effect of temperature, casting rate, rheology, types of pressure sensors, geometry and workability. Considering these various factors, the paper discussed major factors related to lateral pressure of SCC at early ages. However, internal temperature measurement of concrete effects at fresh state appears to be an important factor.

Implementation of Fuzzy Logic Controller for Pressure Sensor Calibration Chamber

Atmospheric pressure is a weather element that must be observed in the field of meteorology. Electronic barometers, aneroid barometers, mercury barometers are generally instruments for atmospheric pressure measurement. The barometer must be calibrated periodically to ensure the performance of the instrument. To achieve the best target uncertainty during calibration, besides using an accurate primary standard barometer, a stable pressure controller is also needed. Pressure calibration media using a pressurised test chamber is more beneficial due to its capability to accommodate all types of pressure sensors. However, pressurise test chamber still requires an operator to control and stabilise pressure inside the test chamber. In this study, fuzzy logic has been programmed into a microcontroller to control the solenoid valve and vacuum pump for regulating air pressure inside a pressurised test chamber automatically. Fuzzy logic changes the solenoid valve states periodically by varying the opening and closing times. The final result of this study is a comparison between the calibration results using pressure controller with fuzzy logic and without fuzzy logic with the same primary standard and unit under test. The result of expanded uncertainty without a fuzzy logic controller is 13.06 hectopascal. Meanwhile, the pressure calibration process using fuzzy logic to control pressure in pressurised test chamber achieve 0.09 hectopascal of expanded uncertainty in 1000 hectopascal pressure value with coverage factor, k=2, and confidence level of no less than 95 %.

A Comparative Study of BaTiO3/PDMS Composite Film and a PVDF Nanofiber Mat for Application to Flexible Pressure Sensors

Intensive research has been conducted to develop flexible piezoelectric pressure sensors, since selfpowering devices are advantageous for wearable electronic applications. Recently, two types of piezoelectric devices, ceramic-PDMS composite film and PVDF nanofiber mats, have drawn attention in the research community. Piezoelectric ceramics such as BaTiO3 (BTO) and PZT exhibit outstanding piezoelectric coefficients, while PDMS provides flexibility. In contrast, a PVDF nanofiber mat simultaneously exhibits piezoelectricity and flexibility. In the present study, a comparative analysis of BTO-PDMS composite film and a PVDF nanofiber mat for application to flexible pressure sensors was carried out. First, step-wise electric poling was conducted on these two types of pressure sensors, after which the open-circuit voltage (Voc) was measured under compressive force. The 1.8 V peak-to-peak Voc was measured in a BTO-PDMS composite with a 30 wt.% BTO content that was poled by 10 kV/mm electric field for 15 min. This peak-to-peak Voc of the BTO-PDMS composite increased further to ~ 4 V when it was poled for 24 hr. Unlike the BTO-PDMS composite films, the maximum Voc (1.1 V) was measured in a PVDF nanofiber mat that did not undergo subsequent electric poling. A BTO-PDMS composite film and a PVDF nanofiber mat were fabricated, and the compressive force and strain-rate dependencies of Voc and the short-circuit current (Isc) were investigated. Overall, the Voc and Isc of the BTO-PDMS composite film exceeded those of the PVDF nanofiber mat in a force range of 1 − 25 N and frequency range of 0.5 − 2.0 Hz. However, the Voc and Isc signals from the PVDF nanofiber mat were more stable than those from the BTO-PDMS composite film due to the longer lifetime of the signals.

Pressure measurements in detonation engines

The influence of waveguide tubes on the signals received by remote pressure sensors measuring pressure histories in pulsed detonation engines (PDEs) and rotating detonation engines (RDEs) is studied computationally. Two types of pressure sensors are considered: low-frequency static pressure sensors and high-frequency sensors of pressure pulsations. Three approaches to solving the problem are used: based on Euler (inviscid flow), Navier–Stokes (laminar flow), and unsteady Reynolds-averaged Navier–Stokes (turbulent flow) equations. The approaches based on the inviscid and laminar flow models are shown to provide the best predictive capability. The laminar flow model is applied to analyzing the readings of pressure sensors installed remotely in the waveguide tubes attached to the hydrogen-fueled PDE, RDE, and detonation ramjet (DR). It is shown that the measurements of static pressure and pressure pulsations by remote pressure sensors do not correspond to the time-averaged mean and local instantaneous values of pressure in the combustors. The pressure time histories can be recovered based on the measurements and computational fluid dynamics calculations of the operation process. The latter is demonstrated by analyzing the results of test fires with a dual-duct DR model.

Validation of Heat-Level Vapor Phase Soldering Process and Workspace Leakage Detection with Applied Pressure Sensors

Electronic manufacturing principles are continuously developing, further improving assembly quality and productivity. There is a continuous need to apply novel and improved methods of process monitoring to provide accurate measurement and control during assembling. In this paper, a new principle for monitoring filmwise condensation-based heat-level—vapour phase soldering (HL-VPS) is presented to improve the process control. The experiment is based on thermocouple sensors in fusion with a sensitive gauge type pressure sensor. The aim is to precisely identify the steps of condensation-based reflow heat transfer process with commercially available components and the mindset of possible retrofitting in the generally used HL-VPS soldering ovens. It was found that the gauge sensor can follow the state of the workspace more precisely as the thermocouples, by monitoring the hydrostatic state of the vapour. The pressure (time) function gives information about the build-up of the vapour column, highlighting four characteristic steps (phases) of the process, meaning: immersion of the sample to be soldered, condensation-based heat transfer, solder-break, and cooling. Combined application with thermocouples enables more precise control, improving soldering quality and can reduce idle time of the oven. In addition, it was showed that the gauge type sensors could highlight any failure in the oven sealing by a sensor signal threshold detection. The original concept of workspace identification also fits the present and future industry 4.0 directives.