Low-cost Pressure Sensor Research Articles

Fabrication of Novel PEO–PVA/SrTiO3–CoO Nanostructures for Low-Cost Pressure Sensor and Gamma-Ray Shielding

Fabrication of Novel PEO–PVA/SrTiO3–CoO Nanostructures for Low-Cost Pressure Sensor and Gamma-Ray Shielding

A Practical, Adaptive, and Scalable Real-Time Control Approach for Stormwater Storage Systems

Traditionally, urban stormwater infrastructure systems consist of passive infrastructure that is not actively controlled in response to rainfall events. Recently, real-time control (RTC) has been considered as a means to significantly increase the capacity and lifespan of these systems. This paper introduces the target flow control systems (TFCS) approach, which can use real-time control of systems of storages to achieve the desired flow conditions at the locations of interest. The first distinctive feature of this approach is that it does not require calibration to catchment-specific data, unlike existing approaches. This means that the TFCS approach is generally applicable to different catchments and is able to respond to future changes in runoff due to land use and/or climate change. The second distinctive feature is that the approach only requires storage-level information measured in real time with the aid of low-cost pressure sensors. This means that the approach is practical and relatively easy to implement. In addition to the introduction of the novel TFCS approach, a key innovation of this study is that the approach is tested on three case studies, each with different physical configurations and stormwater management objectives. Another key innovation is that the TFCS approach is compared to five RTC approaches, including three of the best-performing advanced approaches from the literature. Comparisons of multiple RTC approaches that consider both performance and practicality across multiple case studies are rare. Results show that the TFCS approach is the only one of the five control approaches analysed that has both the best overall performance and the highest level of practicality. The outcomes highlight the potential of the TFCS approach as a practical RTC approach that is applicable to a wide range of catchments with different stormwater management objectives. By maximizing the performance of existing stormwater storages, the TFCS approach can potentially extend the lifespan of existing infrastructure and avoid costly upgrades due to increased runoff caused by land use and climate change.

High-accuracy height differences using a pressure sensor for ground control points measurement in underwater photogrammetry

Abstract. Three-dimensional reference points (RPs) are fundamental for datum definition and metric validation in many photogrammetric applications, often used as ground control points (GCPs) to constrain the bundle adjustment solution. Nevertheless, survey operations underwater present challenges due to the physical characteristics of the water itself and the technological limitations of available instruments. Traditional methods to collect RPs underwater rely on direct geodetic measurements like slope distances, height differences, and depths from a dive computer. These methods can be time-consuming and impractical to scale up to large areas, particularly in deeper waters. This paper reports on the use of a custom-developed low-cost pressure sensor to measure depths and height differences of underwater RPs with survey-grade accuracy. Laboratory and open water tests demonstrated the method's potential, achieving an RMSEZ of less than 1 mm over a 1.5 m height range in the laboratory in static water and a sub-centimetre RMSE of relative depth differences in shallow water tests carried out in two different locations at sea with maximum significant wave height of 9 cm. The sensor proved its effectiveness also for constraining a corridor-like underwater photogrammetric survey reducing the bending of the 3D model with respect to the free network solution (RMSEZ lowered from 10 cm to less than 1 cm). The preliminary tests with the presented approach proved several advantages against other consolidated methods, including cost reduction (compared to commercial survey instruments), rapidity, safety, and accuracy, especially at depths greater than 3–5 m where other approaches (e.g., GNSS or topographic measures) cannot be applied.

Development of planar pressure sensors based on SWCNTs and Poly(aniline)

Planar flexible pressure sensors were produced with single-walled carbon nanotubes (SWCNTs) and poly(aniline) (PANI) composite. Both materials have been processed as films from liquid suspension onto poly(ethylene) terephthalate (PET) substrate, using indium tin oxide electrodes as lateral electrodes. In this device geometry, the pressure can be applied uniformly to the sensing material, reducing its cross-sectional area, and thus increasing the electrical resistance. After pressure removal, the resistance recovers the initial value, a reversible process that can be used in cycles to monitor pressure variations in larger areas and ranges. This device presents a more linear response when compared with layered pressure sensors, where the sensitivity is commonly limited by the mechanical failure of the bottom/top electrodes. Therefore, this approach can be adapted to produce low-cost pressure sensors that allow the monitoring of larger pressure values (up to ∼ 2.2 MPa). The sensor also responds to lower pressure values being applied in punctual regions, in this case, the electrical resistance drops because the sensor responds as an equivalent parallel resistance.

Optoelectronic Pressure Sensor Based on the Bending Loss of Plastic Optical Fibers Embedded in Stretchable Polydimethylsiloxane.

We report the design and testing of a sensor pad based on optical and flexible materials for the development of pressure monitoring devices. This project aims to create a flexible and low-cost pressure sensor based on a two-dimensional grid of plastic optical fibers embedded in a pad of flexible and stretchable polydimethylsiloxane (PDMS). The opposite ends of each fiber are connected to an LED and a photodiode, respectively, to excite and measure light intensity changes due to the local bending of the pressure points on the PDMS pad. Tests were performed in order to study the sensitivity and repeatability of the designed flexible pressure sensor.

Low-Cost Sensor for Continuous Measurement of Brix in Liquids

This paper presents a Brix sensor based on the differential pressure measurement principle. Two piezoresistive silicon pressure sensors were applied to measure the specific gravity of the liquid, which was used to calculate the Brix level. The pressure sensors were mounted inside custom-built water-tight housings connected together by fixed length metallic tubes containing the power and signal cables. Two designs of the sensor were prepared; one for the basic laboratory testing and validation of the proposed system and the other for a fermentation experiment. For lab tests, a sugar solution with different Brix levels was used and readings from the proposed sensor were compared with a commercially available hydrometer called Tilt. During the fermentation experiments, fermentation was carried out in a 1000 L tank over 7 days and data was recorded and analysed. In the lab experiments, a good linear relationship between the sugar content and the corresponding Brix levels was observed. In the fermentation experiment, the sensor performed as expected but some problems such as residue build up were encountered. Overall, the proposed sensing solution carries a great potential for continuous monitoring of the Brix level in liquids. Due to the usage of low-cost pressure sensors and the interface electronics, the cost of the system is considered suitable for large scale deployment at wineries or juice processing industries.

Pomegranate-Inspired Biomimetic Pressure Sensor Arrays With a Wide Range and High Linear Sensitivity for Human–Machine Interaction

Flexible, highly sensitive, easy fabricating process, low-cost pressure sensors are the trend for flexible electronic devices. Despite the tremendous progress in recent years, it is still challenging to prepare pressure sensors with high sensitivity, high stability, and fast responsiveness. In this study, we report a simple and low-cost method for the preparation of novel pressure sensors. Inspired by the pomegranate structure, a 3-D porous structure consisting of polystyrene (PS) microspheres filled with reduced graphene oxide (rGO) paper is proposed. This pressure sensor has high linear sensitivity (1.41 kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> in the pressure range of 0–50 kPa), high stability (1000 cycles), and quick response time (~20 ms). Furthermore, a robotic arm interacting control system based on pressure sensor arrays is constructed, which demonstrates the far-reaching potential of pressure sensors in human–machine interaction. Therefore, this work provides a low-cost and effective method for preparing high linear sensitivity pressure sensors.

Smart Wearable, Highly Sensitive Pressure Sensor with MWNTs/PPy Aerogel Composite

The fabrication of highly sensitive, low-cost pressure sensors with reliable detection performance has received plenty of attention as there is an urgent need for body movement detection and monitoring devices in different fields. The MWNTs/PPy AG composite based piezo-resistive pressure sensor was fabricated using two coating processes. The first coating was with multi-walled carbon nanotubes (MWNTs) and the second was poly-pyrrole (PPy) coating with in situ polymerization performed on commercially available aerogel (AG) as the substrate. The poly-dopamine (PDA) coating was applied as a substrate surface modification method to investigate its effect to enhance the conductivity, sensitivity and other performance aspects of MWNTs AG, PPy AG and MWNTs/PPy AG. An anionic surfactant, sodium dodecyl benzene sulfonate (SDBS) was used as the dispersing agent to prepare a homogeneously mixed MWNTs aqueous solution, which was then used as a scouring agent to remove an existed surface coating on the AG. The retained SDBS in the MWNTs AG worked as a dopant with pyrrole in situ polymerization to improve the conductivity. MWNTs/PPy AG pressure sensor shows high sensitivity (34.64 kPa−1 with 1 kPa), acceptable conductivity and good stability over 5000 continues pressure cycles in the 0.45–4 kPa pressure range. Lowest detection level of MWNTs/PPy AG was close to 0.2 kPa. The MWNTs/PPy AG composite shows promising performance in detecting human body movements in the medium pressure range, which is generally used for health care, rehabilitation and aesthetic purpose.

Low-Cost Pressure Sensors Fabricated from Novel Polymeric Nanocomposites

Nanocomposites (NCs) can be used in several fields, for example, solar cells, biosensors, diodes, antibacterial, transistors…etc. In this paper,(poly (ethylene oxide)-polyvinylpyrrolidone-silicon oxide nanoparticles-manganese dioxide nanoparticles) NCs have been manufactured for pressure sensors with low weight, high sensitivity and lowcost. The nanocomposites were made up of various concentrations of poly (ethylene oxide) (PEO)-polyvinyl pyrrolidone (PVP)-silicon dioxide nanoparticles (SiO2 NPs) and manganese dioxide nanoparticles (MnO2 NPs). The electrical conductivity and dielectric properties of the nanocomposite are studied at room temperature. The dielectric properties of the NCs are examined in the frequency range (100 Hz–5 MHz). The AC electrical conductivity, dielectric constant, and dielectric losses increase with the weight percentages of MnO2 NPs. The dielectric constants and dielectric losses decrease when a frequency increases. The A. C electrical conductivity increases with the concentration of MnO2 NPs and the frequency. The nanocomposite was tested for the pressure sensors application in the pressure range (80–160) bar. The experimental results show that the electric capacitance of nanocomposites samplesis increased, as the pressure increases. Also, the electric capacitance of NCs increases with an increase in the weight percentages of MnO2 NPs. The NCs has a high sensitivity to pressure.

A Low-Cost Pressure Sensor Matrix for Activity Monitoring in Stroke Patients Using Artificial Intelligence

Muscle weakening is a common consequence of stroke and can result in a reduction in physical activity of the affected body part. Therapy includes a range of physical exercises that will help the patients restore and build physical strength, endurance, flexibility, balance, and stability. In order to analyze and recognize the activity and movement of hands while performing these exercises, we have developed a 4×4 flexible pressure sensor matrix to quantize the performance and progress of a patient undergoing physiotherapy. We have also developed an artificial intelligence (AI) based algorithm to determine the accuracy of positioning by the patients. Experimental results demonstrate that the algorithm gives a mean error of 0.103 cm in detecting the position of load, compared to a mean error of 0.704 cm using mathematical analysis. With this system, a patient can be asked to move a weight to a particular location (as part of regular physiotherapy) and the pressure sensor matrix can be used to calculate error in positioning along with the time taken to complete the task. Advantages of the proposed pressure sensor matrix are cost effectiveness, facile fabrication, high sensitivity, robustness and flexibility.

Fabrication and characteristics of flexible, lightweight, and low-cost pressure sensors based on PVA/SiO2/SiC nanostructures

Fabrication and characteristics of flexible, lightweight, and low-cost pressure sensors based on PVA/SiO2/SiC nanostructures

Development of a Low-cost Pressure Sensor

In this paper development of a pressure sensor has been discussed. The main benefit of this sensor is relatively cheap compared to commercially available ones. The unit contains a beam type load cell and a pneumatic cylinder. The load cell has 4 strain gauges in Wheatstone bridge configuration in order to convert the change of resistance into measurable voltage. The system is well applicable in numerous circumstances, where digital pressure signal is necessary for control or data acquisition.

Development of a Low-cost Pressure Sensor

In this paper development of a pressure sensor has been discussed. The main benefit of this sensor is relatively cheap compared to commercially available ones. The unit contains a beam type load cell and a pneumatic cylinder. The load cell has 4 strain gauges in Wheatstone bridge configuration in order to convert the change of resistance into measurable voltage. The system is well applicable in numerous circumstances, where digital pressure signal is necessary for control or data acquisition.

A Real-Time Patient-Specific Sleeping Posture Recognition System Using Pressure Sensitive Conductive Sheet and Transfer Learning

Sleeping is an indispensable activity of human beings. Sleeping postures have a significant effect on sleeping quality and health. A real-time low-cost sleeping posture recognition system with high privacy and good user experience is desired. In this article, we propose a sleeping posture recognition system based on a low-cost pressure sensor array which consists of conductive fabric and conductive wires. The sensor array is deployed as a bedsheet with 32 rows and 32 columns resulting in 1024 nodes. An Arduino Nano performs data collection using a 10-bit Analog to Digital Converter (ADC). The sampling rate of the overall sensor array is 0.4 frame/sec. Six health-related sleeping postures of five participants can be recognized by a shallow Convolutional Neural Network (CNN) deployed on a Personal Computer (PC). The system accuracy achieved 84.80% using the standard training-test method and 91.24% using the transfer learning-based subject-specific method. The real-time processing speed achieved 434 us/frame.

Ultra-small pressure sensors fabricated using a scar-free microhole inter-etch and sealing (MIS) process

This paper presents a tiny 0.4 mm × 0.4 mm piezoresistive absolute pressure sensor chip with a fabrication cost as low as 0.01 US$/die. With the thin-film under bulk-silicon technique, a very thin but uniform poly-silicon pressure-sensing diaphragm is formed beneath a bulk-silicon beam-island structure to accommodate piezoresistors. The thin diaphragm exhibits a high sensitivity, and the beam-island-reinforced structure helps reduce deflection and improve linearity. The sensor is fabricated using a novel scar-free micro-hole inter-etch and sealing (MIS) process. In this newly developed process, seals are removed from the diaphragm area and placed on both the single-crystalline silicon island and single-crystalline silicon frame surrounding the poly-silicon diaphragm. Thus, the thin diaphragm is kept flat and smooth, thereby enhancing the sensing performance and fabrication yield. More importantly, the diaphragm-beam-island structure is small enough to fabricate sensor chips as small as 0.4 mm × 0.4 mm. With the high-yield process, a very low fabrication cost of 0.01 US$/die is realised owing to a high throughput of 90 000 die per 6 inch wafer. The ultra-small and low-cost pressure sensor exhibits sensitivity of 0.88 mV kPa−1/3.3 V, hysteresis of 0.15% full scale (FS), repeatability error of 0.04% FS, and non-linearity of 0.10% FS. Without any additional thermal compensation method, the sensor exhibits a low temperature coefficient of zero-point offset of −0.064%/°C FS and a temperature coefficient of sensitivity (TCS) of −0.22%/°C within the temperature range from −25 °C to +85 °C, at a full measurement range (i.e. full scale) of 100 kPa. With the new scar-free MIS process, the presented pressure sensor looks promising for smartphones, drones, and other consumer-electronic applications.

Low-Cost, Disposable, Flexible, and Smartphone Enabled Pressure Sensor for Monitoring Drug Dosage in Smart Medicine Applications

Due to the rising cases of a prescribed drug overdose and mishandling of the medication container there is an urgent need to devise a smart technological solution to assist this issue. One of the possible solutions to the above issue is the use of low-cost pressure sensor integrated with the medicine container whose data can be communicated to the dedicated smartphone Android application. Once the patient taps the medicine out, the pressure sensor sends the data to the smartphone which can be monitored by the patient’s family and the sensor can then be discarded. In this work, a simple all paper based pressure sensor to monitor drug dosage is fabricated using Molybdenum disulfide (MoS2) grown on paper with an interdigitated electrode drawn using graphite pencil on paper as electrodes. The sensitivity of the fabricated pressure sensor was found to be 0.32 kPa−1 which is comparable and even better than the pressure sensor fabricated using sophisticated techniques. Repeatability of the sensor over 2000 cycles indicates an excellent long-term stability. Bending cycle studies over 1000 cycles observes a negligible change in the performance suggesting the high reliability of the sensor. The fabricated pressure sensor was integrated successfully in the medicine package to monitor the real time pills intake by a patient which shows high promise for its use in health care industry. The successful demonstration of the smart drug dosage system is a step ahead in health care industry which opens up many avenues of research in the similar field.

Low-cost eddy covariance: a case study of evapotranspiration over agroforestry in Germany

Abstract. Heterogeneous land surfaces require multiple measurement units for spatially adequate sampling and representative fluxes. The complexity and cost of traditional eddy covariance (EC) set-ups typically limits the feasible number of sampling units. Therefore, new low-cost eddy covariance systems provide ideal opportunities for spatially replicated sampling. The aim of this study was to test the performance of a compact, low-cost pressure, temperature and relative humidity sensor for the application of evapotranspiration measurements by eddy covariance over agroforestry and conventional agriculture in Germany. We performed continuous low-cost eddy covariance measurements over agroforestry and conventional agriculture for reference at five sites across northern Germany over a period of 2 years from 2016 to 2017. We conducted side-by-side measurements using a roving enclosed-path eddy covariance set-up to assess the performance of the low-cost eddy covariance set-up. Evapotranspiration measured with low-cost eddy covariance compared well with fluxes from conventional eddy covariance. The slopes of linear regressions for evapotranspiration comparing low-cost and conventional eddy covariance set-ups ranged from 0.86 to 1.08 for 5 out of 10 sites, indicating a 14 % flux underestimation and a 8 % flux overestimation relative to the conventional eddy covariance set-up, respectively. Corresponding coefficients of determination, R2, ranged from 0.71 to 0.94 across sites. The root-mean-square error for differences between latent heat fluxes obtained by both set-ups were small compared to the overall flux magnitude, with a mean and standard deviation of 34.23±3.2 W m−2, respectively, across sites. The spectral response characteristics of the low-cost eddy covariance set-up were inferior to the eddy covariance set-up in the inertial sub-range of the turbulent spectrum. The water vapour flux co-spectrum of the low-cost eddy covariance set-up underestimated the theoretical slope of -4/3, stronger than the conventional eddy covariance set-up. This underestimation was mainly caused by the limited response time of the low-cost thermohygrometer being longer than 1 s. We conclude that low-cost eddy covariance sensors are an alternative to conventional eddy covariance sensors when, first, replicates are required and, second, the spatial variability of fluxes of the ecosystems of interest is larger than above-reported set-up-specific differences in fluxes.

A Flexible and Highly Sensitive Pressure Sensor Based on AgNWs/NRLF for Hand Motion Monitoring.

Flexible, highly sensitive, easy fabricating process, low-cost pressure sensors are the trend for flexible electronic devices. Inspired by the softness, comfortable, environmental friendliness and harmless of natural latex mattress, herein, we report an agile approach of constructing a flexible 3D-architectured conductive network by dip-coating silver nanowires (AgNWs) on the natural rubber latex foam (NRLF) substrate that provide the 3D micro-network structure as the skeleton. The variation of the contact transformed into the electrical signal among the conductive three-dimensional random networks during compressive deformation is the piezoresistive effect of AgNWs/NRLF pressure sensors. The resulting AgNWs/NRLF pressure sensors exhibit desirable electrical conductivity (0.45–0.50 S/m), excellent flexibility (58.57 kPa at 80% strain), good hydrophobicity (~128° at 5th dip-coated times) and outstanding repeatability. The AgNWs/NRLF sensors can be assembled on a glove to detect hand motion sensitively such as bending, touching and holding, show potential application such as artificial skin, human prostheses and health monitoring in multifunctional pressure sensors.

A laser ablated graphene-based flexible self-powered pressure sensor for human gestures and finger pulse monitoring

Flexible triboelectric nanogenerators (TENGs)-based pressure sensors are very essential for the wide-range applications, comprising wearable healthcare systems, intuitive human-device interfaces, electronic-skin (e-skin), and artificial intelligence. Most of conventional fabrication methods used to produce high-performance TENGs involve plasma treatment, photolithography, printing, and electro-deposition. However, these fabrication techniques are expensive, multi-step, time-consuming and not suitable for mass production, which are the main barriers for efficient and cost-effective commercialization of TENGs. Here, we established a highly reliable scheme for the fabrication of a novel eco-friendly, low cost, and TENG-based pressure sensor (TEPS) designed for usage in self-powered-human gesture detection (SP-HGD) likewise wearable healthcare applications. The sensors with microstructured electrodes performed well with high sensitivity (7.697 kPa−1), a lower limit of detection (∼ 1 Pa), faster response time ( 4,000 compression-releasing cycles. The proposed method is suitable for the adaptable fabrication of TEPS at an extremely low cost with possible applications in self-powered systems, especially e-skin and healthcare applications.

Ultrawide Sensing Range and Highly Sensitive Flexible Pressure Sensor Based on a Percolative Thin Film with a Knoll-like Microstructured Surface.

Flexible pressure sensors have attracted considerable research interest and efforts owing to their broad application prospects in wearable devices, health monitoring, and human-machine interfacing. High-sensitivity, wide-workable-range, and low-cost pressure sensors are the primary requirement in practical application. In this work, flexible pressure sensors with high sensitivity in a wide pressure range are constructed by introducing a knoll-like microstructured surface into a percolative thermoplastic polyurethane/carbon black sensitive film, using a facile, efficient, and cost-effective screen-printing route. The prepared pressure sensors exhibit an ultrawide sensing pressure range of 0-1500 kPa, high sensitivity (5.205 kPa-1 in the range of 0-100 kPa and 0.63 kPa-1 over 1200 kPa), fast response, and excellent durability for more than 30 000 cycles. We demonstrated the applications of our pressure sensors in health monitoring, such as detection of wrist radial artery pulse waves, phonation, and vibrations. In addition, the proposed sensors showed the potential in object manipulation and human-machine interfacing, capable of detecting spatial pressure distribution, measuring grip forces, and monitoring gas pressures.