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Smartphone sensors are gaining research interest due to continuous sensor upgrades, leading to more precise readings of these sensors. For this study, the light sensor of a smartphone was used in determining light transmittance during the phase inversion process of ultrafiltration polysulfone - membrane manufacturing. Membrane separation is one of the best available technologies when it comes to water and wastewater treatment. The purpose of this study was to correlate light transmit tance, at certain demixing steps during phase inversion, with membrane porosity, pure water flux and cross - sectional SEM images. Results show close relation between light transmittance and the mentioned membrane properties.

Two-dimensional materials, including molybdenum disulfide (MoS2), present promising sensing and detecting capabilities thanks to their extreme sensitivity to changes in the environment. Their reduced thickness also facilitates the electrostatic control of the channel and opens the door to flexible electronic applications. However, these materials still exhibit integration difficulties with complementary-MOS standardized processes and methods. The device reliability is compromised by gate insulator selection and the quality of the metal/semiconductor and semiconductor/insulator interfaces. Despite some improvements regarding mobility, hysteresis and Schottky barriers having been reported thanks to metal engineering, vertically stacked heterostructures with compatible thin-layers (such as hexagonal boron nitride or device encapsulation) variability is still an important constraint to sensor performance. In this work, we fabricated and extensively characterized the reliability of as-synthesized back-gated MoS2 transistors. Under atmospheric and room-temperature conditions, these devices present a wide electrical hysteresis (up to 5 volts) in their transfer characteristics. However, their performance is highly influenced by the temperature, light and pressure conditions. The singular signature in the time response of the devices points to adsorbates and contaminants inducing mobile charges and trapping/detrapping carrier phenomena as the mechanisms responsible for time-dependent current degradation. Far from being only a reliability issue, we demonstrated a method to exploit this device response to perform light, temperature and/or pressure sensors in as-synthesized devices. Two orders of magnitude drain current level differences were demonstrated by comparing device operation under light and dark conditions while a factor up to 105 is observed at vacuum versus atmospheric pressure environments., European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie grant agreement No 895322, Spanish Government under Juan de la Cierva Formacion grant number FJC2018-038264-I, Spanish Ministry of Economy, Industry and Competitivity under grant TEC2017-89800-R, ASCENT (EU Horizon 2020 GRANT 654384), Science Foundation Ireland through the AMBER 2 project (12/RC/2278-P2), UGR-MADOC CEMIX 2D-EDEX

An optofluidic light detector based on the photoacoustic effect is presented. The device performances are tested at 532 nm using a pulsed solid-state laser as light source and a potassium permanganate (KMnO4) water solution as active medium. As expected, the device shows linear response with respect to applied light irradiance. By changing flow rate the device sensitivity increases non-linearly. This change in sensitivity is mainly attributed to a rise in water temperature as the flow rate increases, leading to a higher thermal expansion coefficient. Changes of water temperature with applied flow rate are confirmed through independent fluorescence intensity experiments with Rhodamine B in water. Comparison of the photoacoustic and fluorescence data points out that the change in temperature inside the microfluidic device is not promoted by the absorbed laser light, but instead is mainly due to viscous friction.

Background: HemoSep® is a commercial ultrafiltration and haemoconcentration device for the concentration of residual bypass blood following surgery. This technology is capable of reducing blood loss in cardiac and other types of “clean site” procedures, including paediatric surgery. Clinical feedback suggested that the device would be enhanced by including a sensor technology capable of discerning the concentration level of the processed blood product. We sought to develop a novel sensor that can, using light absorption, give an accurate estimate of packed cell volume (PCV). Materials and methods: A sensor-housing unit was 3D printed and the factors influencing the sensor’s effectiveness – supply voltage, sensitivity and emitter intensity - were optimised. We developed a smart system, using comparator circuitry capable of visually informing the user when adequate PCV levels (⩾35%) are attained by HemoSep® blood processing, which ultimately indicates that the blood is ready for autotransfusion. Results: Our data demonstrated that the device was capable of identifying blood concentration at and beyond the 35% PCV level. The device was found to be 100% accurate at identifying concentration levels of 35% from a starting level of 20%. Discussion: The sensory capability was integrated into HemoSep’s® current device and is designed to enhance the user’s clinical experience and to optimise the benefits of HemoSep® therapy. The present study focused on laboratory studies using bovine blood. Further studies are now planned in the clinical setting to confirm the efficacy of the device.

This paper presents a fully integrated photodiode-based low-power and low-mismatch stimulator for a subretinal prosthesis. It is known that a subretinal prosthesis achieves 1600-pixel stimulators on a limited single-chip area that is implanted beneath the bipolar cell layer. However, the high-density pixels cause high power dissipation during stimulation and high fabrication costs because of special process technologies such as the complementary metal-oxide semiconductor CMOS image sensor process. In addition, the many residual charges arising from the high-density pixel stimulation have deleterious effects, such as tissue damage and electrode corrosion, on the retina tissue. In this work, we adopted a switched-capacitor current mirror technique for the single-pixel stimulator (SPStim) that enables low power consumption and low mismatch in the subretinal device. The customized P+/N-well photodiode used to sense the incident light in the SPStim also reduces the fabrication cost. The 64-pixel stimulators are fabricated in a standard 0.35-&mu, m CMOS process along with a global digital controller, which occupies a chip area of 4.3 &times, 3.2 mm2 and are ex-vivo demonstrated using a dissected pig eyeball. According to measured results, the SPStim accomplishes a maximum biphasic pulse amplitude of 143 &mu, A, which dissipates an average power of 167 &mu, W in a stimulation period of 5 ms, and an average mismatch of 1.12 % between the cathodic and anodic pulses.

We present a low-power low-frequency oscillator that is fully integrated on a bendable plastic substrate using amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). Its purpose is the duty cycling of components of a wireless sensor tag to realize power savings. In addition, the oscillator can directly be used as a light sensor. It oscillates between 5 Hz in the dark and 31 Hz under daylight, from a 5-V supply voltage. The measured light-sensitivity of the oscillation frequency is between 7.4 Hz/klx in the dark and around 1.7 Hz/klx in daylight. On average, the frequency of oscillation changes by 58 %/klx. The required power is 188 $\mu \text{W}$ . The presented design is a combination of the inductance–capacitance cross-coupled oscillator structure and two single-transistor active inductors, which enable high gain at low power levels in a small chip area. We analyze the circuit and derive design guidelines for minimizing the oscillation frequency, circuit area, and power consumption. Finally, we report the measurements including jitter and deduce implications for the accuracy of light measurements.

The rapid increase in vehicle population in recent years have given rise to a number of global problems such as air pollution, blockage of roads, waste of fuel and time. These issues exist due to the congestion caused by vehicles while finding the parking slot especially in metropolitan cities. Even today, many of the existing parking systems provide a passive information to the drivers regarding the availability of parking slots. Currently, the sensors deployed for detecting the vehicle presence in parking facilities are not reliable and are expensive. This paper presents a comprehensive analysis on crucial aspects for designing a smart parking system such as sensor selection and optimal position for sensor deployment for accurate detection. Initially, two most common sensor, Light Dependable Resistor (LDR) sensor that works on shadow detection principal and Infra-Red (IR) sensor which works on object detection mechanism are used. The performance analysis of the accuracy for detection of vacant parking slots and vehicle detection under different conditions is presented. It is concluded that IR sensor outperforms LDR sensor in terms of it's accuracy in detecting the vacant parking slots and vehicle detection in different environmental factors.

Panel system power distribution at Lippo Plaza Mall Sidoarjo consists of several parts, namely from Cubicle 20 KV, 20 KV step-down transformer for 380 V, then the supply to LVMDP (Low Voltage Main Distribution Panel) The new panel to the user. Before delivery to users to note that the power factor is corrected using a capacitor bank. Less good a power factor is turned into inductive load on the capacitor bank so that temperatures high because of high load resulting capacitor bank erupt. To overcome in this study proposes a safety panel automation power distribution control system using a microcontroller. Control system microcontrollers for safety panel power distribution consists of: Microcontroller (Arduino Nano), Light sensor (LDR), temperature sensor (LM35DZ), LCD 16x2 I2C, Actuators (fan, buzzer, relay switch breaker network three phase), switch ( relay 5 VDC), ADC as Input data. The working principle of this microcontroller LM35DZ if the sensor detects a high temperature fan will flash, if the LDR sensor detects sparks then the buzzer will sound as a warning sign of the dangers and disconnected the electricity network. From the design of a safety tool for power distribution panels due to high temperatures or sparks as well as the expected rate of fire outbreaks can be prevented.

Solar energy is considered the greatest source of renewable energy. In this paper, a case study was performed for a single-axis solar tracking model to analyze the performance of the solar panels in an office building under varying ambient temperatures and solar radiation over the course of one year (2018). This case study was performed in an office building at the College of Engineering at Shaqra University, Dawadmi, Saudi Arabia. The office building was supplied with electricity for a full year by the designed solar energy system. The study was conducted across the four seasons of the studied year to analyze the performance of a group of solar panels with the total capacity of a 4 kW DC system. The solar radiation, temperature, output DC power, and consumed AC power of the system were measured using wireless sensor networks (for temperature and irradiance measurement) and a signal acquisition system for each hour throughout the whole day. A single-axis solar tracker was designed for each panel (16 solar panels were used) using two light-dependent resistors (LDR) as detecting light sensors, one servo motor, an Arduino Uno, and a 250 W solar panel installed with an array tilt angle of 21&deg, Finally, an artificial neural network (ANN) was utilized to estimate energy consumption, according to the dataset of AC load power consumption for each month and the measurement values of the temperature and irradiance. The relative error between the measured and estimated energy was calculated in order to assess the accuracy of the proposed ANN model and update the weights of the training network. The maximum absolute relative error of the proposed system did not exceed 2 &times, 10&minus, 4. After assessment of the proposed model, the ANN results showed that the average energy in the region of the case study from a 4 kW DC solar system for one year, considering environmental impact, was around 8431 kWh/year.

We successfully fabricated a planar nanocomposite film that uses a composite of silver nanoparticles and titanium dioxide film (Ag-TiO2) for ultraviolet (UV) and blue light detection and application in ozone gas sensor. Ultraviolet-visible spectra revealed that silver nanoparticles have a strong surface plasmon resonance (SPR) effect. A strong redshift of the plasmonic peak when the silver nanoparticles covered the TiO2 thin film was observed. The value of conductivity change for the Ag-TiO2 composite is 4&ndash, 8 times greater than that of TiO2 film under UV and blue light irradiation. The Ag-TiO2 nanocomposite film successfully sensed 100 ppb ozone. The gas response of the composite film increased by roughly six and four times under UV and blue light irradiation, respectively. We demonstrated that a Ag-TiO2 composite gas sensor can be used with visible light (blue). The planar composite significantly enhances photo catalysis. The composite films have practical application potential for wearable devices.

The paper presents a color sensor system that can process light reflected from a surface and produce a digital output representing the color of the surface. The end-user interface circuit requires only a 3-bit pseudo flash analog-to-digital converter (ADC) in place of the conventional/typical design comprising ADC, digital signal processor and memory. For scalability and compactness, the ADC was designed such that only two comparators were required regardless of the number of color/wavelength to be identified. The complete system design has been implemented in hardware (bread board) and fully characterized. The ADC achieved less than 0.1 LSB for both INL and DNL. The experimental results also demonstrate that the color sensor system is working as intended at 20 kHz while maintaining greater than 2.5 ENOB by the ADC. This work proved the design concept and the system will be realized with integrated circuit technology in future to improve its operating frequency.

In this paper, we present a new method to measure light intensity in a floating body partially depleted SOI MOSFET. The photo-generated charge density in the MOSFET is converted into a charge pumping frequency needed to maintain the drain current at a constant value. This new approach contrasts with conventional techniques that rely on an accurate drain current evaluation. According to our measurements, flux densities as low as 2 mW/m2 were obtained using a regular SOI MOSFET, thus confirming the potentials of this approach. © 2007 Elsevier Ltd. All rights reserved.

23nd Signal Processing and Communications Applications Conference (SIU) -- MAY 16-19, 2015 -- Inonu Univ, Malatya, TURKEY WOS: 000380500900299 Determination of soil texture has always been very important for agricultural researches. Since determination of proportions of sand, silt, and clay in a soil by traditional methods requires more effort, in this study, we focus on performing soil analysis by an automated computerized system. First some features are extracted by applying curve fitting method on time signals measured by a light sensor circuit injected to the traditional hydrometer method, and then these features are used as input in a linear regression model. The obtained results showed that in spite of the limited number of experiments performed, such a system may be useful in determination of proportion of sand in a soil. Dept Comp Engn & Elect & Elect Engn, Elect & Elect Engn, Bilkent Univ

To combine robots with many sensor nodes on the sensor network is important for improving home security. To reduce the cost of such a system, it is desirable that each sensor node is very cheap and very small. The three events which occur to the window and the key when a thief attempts to intrude into a house are conventionally detected by different sensors. This article proposes a method of detecting all three events by using a simple light sensor consisting of an infrared LED and a photodetector. In the experiments, the light sensor shows the characteristic tendencies that can detect each event. This fact indicates that our proposal can realize one sensor node more efficiently than using different sensors., This work was presented in part at the 15th International Symposium on Artificial Life and Robotics, Oita, Japan, February 4–6, 2010

In this paper, an environment knowledge-based multiple sensors indoor positioning system is designed and tested. The system integrates a LiDAR sensor, an odometer and a light sensor onto a low-cost robot platform. While, a LiDAR point-cloud-based pattern match algorithm - Iterative Closed Point (ICP) is used to estimate the relative change in heading and displacement of the platform. Based on the knowledge of the construction's structure, outdoor weather, and lighting situation, the light sensor offers an efficient parameter to improve indoor position accuracy with a light intensity fingerprint matching algorithm on low computational cost. The estimated heading and position change from LiDAR are eventually fused by Extended Kalman Filter (EKF) with those calculated from the light sensor measurement. The results prove that the spatial structure and the ambient light information in indoor environment as knowledge base can be utilized to estimate and mitigate the accumulated errors and inherent drifts of ICP algorithm. These improvements lead to longer sustainable sub meter-level indoor positioning for UGVs.

Exposure to bright light appears to be protective against myopia in both animals (chicks, monkeys) and children, but quantitative data on human light exposure are limited. In this study, we report on a technique for quantifying light exposure using wearable sensors. Twenty-seven young adult subjects wore a light sensor continuously for two weeks during one of three seasons, and also completed questionnaires about their visual activities. Light data were analyzed with respect to refractive error and season, and the objective sensor data were compared with subjects' estimates of time spent indoors and outdoors. Subjects' estimates of time spent indoors and outdoors were in poor agreement with durations reported by the sensor data. The results of questionnaire-based studies of light exposure should thus be interpreted with caution. The role of light in refractive error development should be investigated using multiple methods such as sensors to complement questionnaires.

Nanostructures hold promise as building blocks for a new generation of sensing devices because they could enhance detection and conversion of nonelectrical phenomena into electrical signals. In this paper, we discuss the possible use of a semiconductor (GaAs) nanowire grid as a light sensor. Based on the previously measured electrical properties of a single GaAs nanowire, we propose a model to determine the resistance of a structure consisting of many nanowires forming a grid with metallic contacts. Due to the fact that the proposed geometry is partially disordered, the total resistance of the structure is determined implementing the random resistor network (RRN) methodology in our simulation model. In order to reduce the error caused by condition number and the machine epsilon, the RRN model is improved by introducing additional conditions for solving the transfer matrix formulation precisely. The proposed complex nanowire geometry is analysed for different grid sizes varying the number of nanowires and contacts. According to the nanowire doping profile, we have defined the fraction of active segments (FoS) that is light-sensitive. Simulation results have shown that light sensitivity of a nanowire grid is enhanced with increasing number of active segments while a relative change in the active segment resistance has only a minor influence on the resistance of the complete structure. Finally, we have optimized nanowire grid dimensions with respect to the simulation results and practical limitations.