Advances in Optical Based Turbidity Sensing Using LED Photometry (PEDD)

Fay, Cormac; Nattestad, Andrew

doi:10.3390/s22010254

Cited by 17 publications

(15 citation statements)

References 47 publications

(64 reference statements)

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“…Overall, a comprehensive optical analysis is on our agenda, particularly as we envision the application of this setup for the design of problem-driven sensing technology [59] in optical bio/chemical detection systems during our next stage of development [60,61]. More specifically, given the optical transparency and the potential to form micro-fluidic structures, we aim to utilise computer vision [62][63][64] and/or advancements in LED photometry [65] to develop ultra-low-cost detectors, which have been validated for a number of water targets, such as turbidity [66], pH [67], and nitrite [68].…”

Section: Applicable Areas and Future Directionsmentioning

confidence: 99%

Cost-Effective 3D Printing of Silicone Structures Using an Advanced Intra-Layer Curing Approach

Fay,

2023

Technologies

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We present an advanced, low-cost 3D printing system capable of fabricating intricate silicone structures using commercially available off-the-shelf materials. Our system used a custom-designed, motorised syringe pump with a driving lead screw and excellent control of material extrusion to accommodate the high viscosity of silicone printing ink, which is composed of polydimethylsiloxane (PDMS), diluent, and a photo-initiator (LAP). We modified an open-source desktop 3D printer to mount the syringe pump and programmed it to deposit controlled intricate patterns in a layer-by-layer fashion. To ensure the structural integrity of the printed objects, we introduced an intra-layer curing approach that fused the deposited layers using a custom-built UV curing system. Our experiments demonstrated the successful fabrication of silicone structures at different infill percentages, with excellent resolution and mechanical properties. Our low-cost solution (costing less than USD 1000 and requiring no specialised facilities or equipment) shows great promise for practical applications in areas such as micro-fluidics, prosthesis, and biomedical engineering based on our initial findings of 300 μm width channels (with excellent scope for smaller channels where desirable) and tunable structural properties. Our work represents a significant advance in low-cost desktop 3D printing capabilities, and we anticipate that it could have a broad impact on the field by providing these capabilities to scholars without the means to purchase expensive fabrication systems.

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Section: Applicable Areas and Future Directionsmentioning

confidence: 99%

Cost-Effective 3D Printing of Silicone Structures Using an Advanced Intra-Layer Curing Approach

Fay,

2023

Technologies

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“…The first time the term paired emitter detector diode (PEDD) was used dates back to 1993 [ 33 ]. Since then, this methodology of paring a diode and photodiode has been successfully used for determining water quality parameters (nitrate, nitrogen [ 34 , 35 ], turbidity [ 36 ], phosphate [ 37 ], phosphorous [ 38 ], paraquat and diquat [ 39 ], fluoxetine and citalopram [ 40 ], and chromium [ 41 ]). Use of novel signal processing algorithms that can replace some hardware leads to better instrument performance at a lower cost.…”

Section: Introductionmentioning

confidence: 99%

A Portable Measurement Device Based on Phenanthroline Complex for Iron Determination in Water

Fernandes

Tlemçani

Bortoli

et al. 2023

Sensors

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In this work, a newly developed self-contained, portable, and compact iron measurement system (IMS) based on spectroscopy absorption for determination of Fe2+ in water is presented. One of the main goals of the IMS is to operate the device in the field as opposed to instruments commonly used exclusively in the laboratory. In addition, the system has been tuned to quantify iron concentrations in accordance with the values proposed by the regulations for human consumption. The instrument uses the phenanthroline standard method for iron determination in water samples. This device is equipped with an optical sensing system consisting of a light-emitting diode paired with a photodiode to measure absorption radiation through ferroin complex medium. To assess the sensor response, four series of Fe2+ standard samples were prepared with different iron concentrations in various water matrices. Furthermore, a new solid reagent prepared in-house was investigated, which is intended as a “ready-to-use” sample pre-treatment that optimizes work in the field. The IMS showed better analytical performance compared with the state-of-the-art instrument. The sensitivity of the instrument was found to be 2.5 µg Fe2+/L for the measurement range established by the regulations. The linear response of the photodiode was determined for concentrations between 25 and 1000 µg Fe2+/L, making this device suitable for assessing iron in water bodies.

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Section: Introductionmentioning

confidence: 99%

“…Given that the bulk of the reported implementations of PEDD in the literature involve sensing [32], it is considered necessary to do the same here in order to explore the effects of software and timing aspects when measuring a sensory target. Turbidity was chosen for this purpose as it is a very practical and important indicator for water quality [32]-both for environmental monitoring [33][34][35][36][37][38][39][40][41][42] and for drinking water [43][44][45][46]. For water bodies such as rivers and lakes in the environment, turbidity is a measurement of the degree of 'cloudiness' caused by suspended particles with known contributing sources from human activities such as mining, agriculture or construction [38,39].…”

Section: Introductionmentioning

confidence: 99%

LED PEDD Discharge Photometry: Effects of Software Driven Measurements for Sensing Applications

Fay

Nattestad

2022

Sensors

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This work explores the effects of embedded software-driven measurements on a sensory target when using a LED as a photodetector. Water turbidity is used as the sensory target in this study to explore these effects using a practical and important water quality parameter. Impacts on turbidity measurements are examined by adopting the Paired Emitter Detector Diode (PEDD) capacitive discharge technique and comparing common embedded software/firmware implementations. The findings show that the chosen software method can (a) affect the detection performance by up to 67%, (b) result in a variable sampling frequency/period, and (c) lead to an disagreement of the photo capacitance by up to 23%. Optimized code is offered to correct for these issues and its effectiveness is shown through comparative analyses, with the disagreement reduced significantly from 23% to 0.18%. Overall, this work demonstrates that the embedded software is a key and critical factor for PEDD capacitive discharge measurements and must be considered carefully for future measurements in sensor related studies.

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Advances in Optical Based Turbidity Sensing Using LED Photometry (PEDD)

Cited by 17 publications

References 47 publications

Cost-Effective 3D Printing of Silicone Structures Using an Advanced Intra-Layer Curing Approach

Cost-Effective 3D Printing of Silicone Structures Using an Advanced Intra-Layer Curing Approach

A Portable Measurement Device Based on Phenanthroline Complex for Iron Determination in Water

LED PEDD Discharge Photometry: Effects of Software Driven Measurements for Sensing Applications

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