Intelligent Sensors and Monitoring System for Low-cost Phototherapy Light for Jaundice Treatment

Carlos M. Oppus; Gregory L. Tangonan; Ivan B. Culaba; Jeremie E. De Guzman; Nerissa G. Cabacungan; Paul M. Cabacungan

REVIEW 5 major objections 6 minor 14 references

Intelligent Sensors and Monitoring System for Low-cost Phototherapy Light for Jaundice Treatment

T0 review · 5 major / 6 minor · reviewed 2026-08-14 · deepseek-v4-flash

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Pith's one-line read The ILPLS is an upgraded low-cost LED phototherapy light for newborn jaundice that adds an intelligent sensor and monitoring system while remaining 75% cheaper than a commercial unit and still exceeding the minimum effective irradiance by…

desk verdict A straightforward, useful engineering report on a low-cost phototherapy unit with sensors and solar backup; the clinical claim leans on an unpublished predecessor study and the key irradiance numbers lack audit detail, but the core engineering is plausible. read the letter →

arxiv 1909.01220 v1 pith:2UST4GIN submitted 2019-08-23 physics.med-ph eess.SP

Paul M. Cabacungan , Carlos M. Oppus , Jeremie E. De Guzman , Gregory L. Tangonan , Ivan B. Culaba , Nerissa G. Cabacungan This is my paper · ORCID

classification physics.med-pheess.SP

keywords neonataljaundicephototherapyLEDlow-costmedicaldevicesensormonitoringsolarpower

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper reports an upgraded version of a low-cost LED phototherapy light for newborn jaundice, adding sensors, alarms, remote monitoring, and solar-power capability while keeping the unit 75% cheaper than a commercial phototherapy unit. The central claim is that the upgraded unit still emits more than three times the minimum irradiance needed for effective treatment, so the added intelligence does not compromise the phototherapy function. A sympathetic reader would care because cost and maintenance are the main barriers to jaundice treatment in low-resource hospitals.

What carries the argument

The carrying object is the LED array with engineered beam overlap: bulbs spaced 13 cm apart produce a 43 percent overlap of beams, and crossing beams at 22 cm give 11 percent intersection, so irradiance in the treatment area exceeds the clinical minimum by 300 percent as a degradation margin. Supporting it are light-dependent resistors, a temperature and humidity sensor, microcontrollers, a camera and microphone, and an alarm and timer system, all working with a solar and battery power provision.

What would settle it

Measure the bilirubin decline rate in jaundiced infants treated with the ILPLS and compare with the LPLS and a commercial unit; if the ILPLS does not match or beat the predecessor's 24-hour and 48-hour bilirubin reductions, the carry-over assumption fails.

Watch

Extended reading notes

Core claim

The upgraded ILPLS uses eight 7-watt blue LED spotlights arranged so light beams overlap by 43 percent, producing 90 $\mu$W/cm$^2$/nm at 30 cm against a 30 $\mu$W/cm$^2$/nm minimum. The integrated system reports LED intensity, bulb temperature, and ambient humidity, triggers alarms when readings go critical or bulbs need replacement, and includes a camera and microphone for remote nursing observation. The unit runs 10 hours on two lead-acid car batteries pre-charged by solar panels, and its cost is PhP 35,000 versus PhP 150,000 for the commercial unit.

Load-bearing premise

The clinical benefit of the upgrade is assumed to follow from the predecessor unit's successful clinical study, since the smarter unit's own irradiance is higher but was not directly tested on infants.

Editorial extensions

If this is right

The unit can be deployed in off-grid hospitals using a battery-swapping solar setup that costs about $1,250.
Nurses can remotely monitor infant condition and device status at a nursing station, with data logged to an SD card for patient records.
Alarm and timer functions let staff set exposure time and catch bulb degradation early, preserving therapeutic irradiance.
At 90 $\mu$W/cm$^2$/nm, even the observed 30 percent three-year irradiance drop would leave the unit above twice the minimum.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

The paper does not report clinical outcomes for the ILPLS itself; the cited clinical benefit comes from the earlier LPLS. If the higher irradiance of the ILPLS translates to faster bilirubin decline, treatment duration and unit sharing could drop further.
Using the webcam as a backup intensity monitor, averaging pixel values, is a testable extension that would give whole-body exposure readings without extra hardware.
Cross-calibrating the built-in photodiodes against the reference photometer would let the monitor itself certify when bulbs need replacement, potentially removing the need for periodic technician visits.

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Signed reviews

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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

You should know this paper for what it is: an engineering report on upgrading a locally built LED phototherapy light with sensors, a camera, an alarm, a timer, and a solar/battery option. The upgrade is incremental—the authors say so themselves—but it is a real contribution for low-resource and off-grid settings where premature babies need jaundice treatment and commercial units are unaffordable. The cost comparison (PhP 35,000 versus PhP 150,000 for the commercial unit) is useful, and the design is refreshingly local: off-the-shelf parts, simple electronics, repairable by local technicians. The paper also deserves credit for being honest about the earlier unit's 30% LED degradation over three years and for explicitly recommending cross-calibration of the monitoring photodiodes in Section V. That kind of frankness is not always present in engineering reports.

The soft spots are real but proportional. The load-bearing claim is that the ILPLS emits 90 µW/cm²/nm, three times the 30 µW/cm²/nm minimum. The measurement section says only that an RS PRO ISM 410 was used; there is no calibration procedure, no stated measurement geometry, no bandwidth or filter detail, and no uncertainty. With no error bars, the 300% margin cannot be independently checked. A systematic factor-of-two error would still leave the device above threshold, so the central engineering claim probably survives, but a referee should ask for details. There is also an internal inconsistency: Section IV reports the FWHM as 437.38–457.68 nm with a peak at 447.68 nm, while Table 1 lists 437.8–458.48 nm. That is a small but telling discrepancy in the optical measurements.

The bigger soft spot is clinical. The paper's effectiveness argument rests on an unpublished predecessor study (ref [13]) of the original LPLS. The ILPLS itself has no clinical data. The authors carefully say it "could offer faster treatment," which is appropriately cautious, but the conclusion that the intelligent system was "successfully integrated without affecting the unit's optimal functioning" relies on a 120-hour continuous run, not a controlled comparison with the monitoring system switched off. Those are addressable with more documentation and a direct clinical trial, not fatal flaws.

Who should read this? People working on neonatal care technology for low-resource settings, or anyone designing low-cost medical devices with remote monitoring. It is not a research breakthrough, but it is a competent, reproducible engineering description with a plausible performance claim. I would give it a serious referee, not because it settles any question but because the device could genuinely help, and the engineering details deserve scrutiny that conference-level review may not provide.

Referee Report

5 major / 6 minor

Summary. The paper reports on the design, fabrication, and bench testing of an upgraded low-cost LED phototherapy device for neonatal jaundice, called the Improved Low-cost Phototherapy Light System (ILPLS). The upgrades add a camera/microphone for remote monitoring, microcontroller-based sensors for light intensity, temperature, and humidity, an alarm system, a timer, and a solar-battery power provision. The authors compare the ILPLS with the earlier LPLS prototype and a commercial fluorescent unit, reporting that the ILPLS delivers an irradiance of 90 µW/cm²/nm at 30 cm, exceeding the 30 µW/cm²/nm minimum by a factor of three, that it is about 75% cheaper than the commercial unit, and that a 120-hour continuous stress test ran without issues. They also cite an unpublished predecessor study to argue that the device family is clinically effective, and they frame the ILPLS as offering potentially faster treatment.

Significance. If the engineering and measurement claims are adequately supported, this is a useful contribution to low-resource neonatal care: the system appears inexpensive, locally repairable, and designed around readily available components, and the addition of remote monitoring and alternative power is practically motivated. The paper's strongest assets are the explicit cost comparison, the deployment context, and the clear description of the sensor/monitoring architecture. However, the central quantitative claims—especially the threefold irradiance margin over the treatment threshold—rest on measurements reported without uncertainty, calibration details, or repeated trials, and the clinical-effectiveness argument is extrapolated from an unpublished study of the predecessor device. The paper would be acceptable only after these load-bearing points are addressed.

major comments (5)

[Section IV, Table 1] The central quantitative claim—that the ILPLS delivers 90 µW/cm²/nm, three times the 30 µW/cm²/nm threshold—is not auditable as reported. The text states only that irradiance was measured "Using RS PRO ISM 410" and gives no calibration traceability, no statement of whether the instrument reports spectral irradiance or operates with a specific bandwidth/filter, no spatial sampling protocol over the exposure area, and no uncertainty or repeated-measurement information. Because the margin over the threshold is a factor of three, a systematic calibration or geometry error of a factor of two would invalidate the claim. Please report the measurement protocol, instrument specifications and calibration, measurement positions across the treatment area, and uncertainty estimates.
[Section IV, Table 1, 'Total Power' row] The commercial unit is listed as consuming 400 W while using five 20-W fluorescent bulbs, i.e., only 100 W of lamp load. The 400 W figure may include ballast, fans, and other loads, but the basis is not stated and the other units' power figures are not specified as measured input power either. Please report measured input power for all three units and explain the discrepancy between the 400 W rating and the lamp load.
[Section IV and Table 1] The wavelength reporting is internally inconsistent: the text gives the ILPLS FWHM as 437.38–457.68 nm with a peak at 447.68 nm, while Table 1 lists 437.8–458.48 nm. In addition, the Introduction reports the LPLS wavelength as decreasing from 462.1 nm to 457.15 nm, whereas Table 1 lists the LPLS range as 462.1–476.4 nm. These discrepancies need to be reconciled because phototherapy efficacy depends on spectral overlap with bilirubin absorption and because the paper uses the wavelength range to support clinical effectiveness.
[Section V] The statement that "The improved prototype (ILPLS), which was similar to the first one but used LED spotlights that emitted greater irradiance, could offer faster treatment" is an extrapolation from the unpublished predecessor study by Bagunu and Perez (ref [13]) and is not supported by any clinical data on the ILPLS itself. That study compared the LPLS with conventional fluorescent phototherapy and is not peer-reviewed. Please separate the engineering characterization of the ILPLS from clinical-effectiveness claims, and either remove the "faster treatment" claim or explicitly label it as a hypothesis requiring clinical evaluation.
[Sections IV and V] The claim that the intelligent system was "successfully integrated into the phototherapy light system without affecting the unit's optimal functioning" is not established by the reported 120-hour continuous run, which includes no comparison with the monitoring system disabled. Moreover, Section V itself recommends future cross-calibration of the silicon photodiodes and Webcam sensors, indicating that the monitoring calibration is not yet fully validated. Please provide a controlled comparison of irradiance and temperature with the monitoring system on versus off, and state explicitly which monitoring functions had been calibrated at the time of testing.

minor comments (6)

[Table 1] In the Commercial Unit column, the entry "(5-white, 2-blue)" is ambiguous; clarify whether this is the bulb composition and provide the measured spectral range for that unit rather than only a label.
[Abstract and Section IV] The abstract says the automation system stores data about light intensity, bulb temperature, and ambient humidity, but Section IV does not specify the sensor models, logging interval, or how the stored data were verified; these details should be included for reproducibility.
[Figures] The manuscript refers to Figures 1 through 4, but the text as provided contains no figure images; the final version must include complete figures with axes, labels, and captions, particularly for the LED array layout, block diagrams, and the mock set-up.
[References] Reference [13] is an unpublished submission; if it is the only clinical evidence cited, indicate its status (e.g., under review, thesis, or institutional report) and provide a way for readers to access or verify it.
[Section III] The phrase "engineering margin of 300%" is presented without a precise definition; state explicitly whether this means the measured irradiance is three times the minimum, and describe how the margin accounts for LED aging and measurement uncertainty.
[Section IV, solar powering] The solar-battery sizing calculation is incomplete: report the measured DC load of the ILPLS including sensors and monitoring, the assumed depth of discharge for the lead-acid batteries, and the number of sun-hours assumed for the solar-panel sizing.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the irradiance, cost, and sensor-monitoring claims are externally measured and benchmarked, and the clinical extrapolation to the ILPLS is explicitly hedged rather than derived from its own inputs.

full rationale

The paper's central engineering claims are empirical and externally anchored. The irradiance values in Table 1 (84, 90, and 70 µW/cm²/nm for LPLS, ILPLS, and the commercial unit) are presented as measurements made with the RS PRO ISM 410 photometer, and the wavelength measurements were taken with an Ocean Optics USB 4000 spectrometer; these are independent instruments, not quantities fitted from the paper's own assumptions. The comparison against the 30 µW/cm²/nm treatment threshold is a direct benchmark, and the cost comparison is a straightforward procurement calculation. The intelligent sensor and monitoring system was tested by continuous 120-hour operation and by a laboratory transmission test, so its functionality claim is self-contained. The only potentially self-referential element is reference [13], the unpublished Bagunu and Perez study of the predecessor LPLS, which is used to support the statement that the LPLS was clinically effective. That study is by acknowledged clinical collaborators, not by the present authors, and it is not used to define or derive the ILPLS's measured performance. Moreover, the paper does not assert a proven clinical benefit for the ILPLS itself; it says only that the ILPLS 'could offer faster treatment' because it is similar to the first prototype and emits greater irradiance. That is an explicitly hedged extrapolation and a limitation, not a circular reduction. The paper also candidly recommends cross-calibration of the silicon photodiodes and webcam sensors, acknowledging that some monitoring calibration remains unfinished, which further supports that the engineering results are not presented as closed-loop derivations. In short, there is no equation, fitted parameter, or self-citation chain that makes any claimed output equivalent by construction to its input.

Assumptions & free parameters 1 free parameters · 3 assumptions · 0 invented entities

The paper introduces no new physical entities and fits no numerical parameters to data. The only hand-set design margin is the 300% irradiance margin. The main external support is a set of domain assumptions about phototherapy effectiveness and an unpublished predecessor study.

free parameters (1)

Engineering margin of 300% = 3x minimum irradiance
Chosen by hand to accommodate the observed 30% LED degradation over three years; no formal calculation connects the margin to the degradation plus safety factor.

assumptions (3)

domain assumption Phototherapy is effective when irradiance is at least 30 µW/cm²/nm
Used in Section IV to judge the device adequate; based on phototherapy literature (ref [14]) not derived in this paper.
domain assumption The unpublished clinical study of the earlier LPLS (Bagunu and Perez, ref [13]) is valid and applicable to the ILPLS
Section V uses this study to claim the ILPLS could offer faster treatment, despite no ILPLS-specific clinical data.
domain assumption LED peak wavelength near 447 nm overlaps the bilirubin absorption spectrum sufficiently for treatment
Section III states the 400-500 nm range is used for phototherapy; accepted domain knowledge.

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Cite this review

Pith. "Pith review of Intelligent Sensors and Monitoring System for Low-cost Phototherapy Light for Jaundice Treatment." pith.science (2026). https://pith.science/paper/2UST4GIN

@misc{pith2026190901220,
  author       = {Pith},
  title        = {Pith review of: Intelligent Sensors and Monitoring System for Low-cost Phototherapy Light for Jaundice Treatment},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/2UST4GIN}},
  note         = {Machine review of arXiv:1909.01220}
}

read the original abstract

A prototype of a low-cost phototherapy light system (LPLS) was deployed by the Ateneo Innovation Center (AIC) at a public hospital in Metro Manila, Philippines. It underwent clinical investigation for two years under the supervision of licensed physicians in a public tertiary hospital. This paper presents the process of upgrading the LPLS in order to enhance capabilities and improve efficiency yet remain affordable. The following features were added: (1) a visual and auditory monitoring system in order to remotely oversee the infant from the nurse station; (2) an automation system that stores data about the device's light intensity and bulb temperature and records ambient humidity; (3) an alarm system that activates the warning lights if sensor readings are in critical level and if the bulbs need to be replaced; and (4) a time setting to manually set the time of operation and automatically turn-off the device as programmed. The upgrades increased the system's cost but it remained cheaper than the ones commercially available. For deployment in remote or off-grid hospitals, the system was equipped with a solar-powering provision.

Figures

Figures reproduced from arXiv: 1909.01220 by the authors.

**Figure 2.** LED array with two ventilation fans. Despite the distance, light intensity in the area covered by overlapping beams still fell within the range of required irradiance for jaundice treatment. We also purposely designed the LED array so the irradiation patterns overlapped in the exposure area covering 150% of the 45-centimeter average infant length. Light intensity was determined with a photodetector that was calibrat… view at source ↗

**Figure 3.** Block diagram of the improved low-cost phototherapy [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗

**Figure 4.** Mock set-up of the improved low-cost phototherapy light [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

14 extracted references · 14 canonical work pages

[13]

Bagunu, M

V . Bagunu, M. Perez, Comparative study of Prototype Low- Cost Light Emitting Diode Phototherapy Device versus Conventional Fluorescent Phototherapy in the Treatment of Indirect Hyperbilirubinemia among Term Infants in a Tertiary Government Hospital, submitted to Philippine Pe- diatric Society, unpublished, 2018

work page 2018
[1]

Henny-Harry and H

C. Henny-Harry and H. Trotman, Epidemiology of Neonatal Jaundice at the University Hospital of the West Indies, The West Indian Medical Journal, vol. 61(1), pp. 37-42, 2012

work page 2012
[2]

Lewis, Temporal Control in Phototherapy, United States Patent Application Publication, Pub

C. Lewis, Temporal Control in Phototherapy, United States Patent Application Publication, Pub. No.: US 2008/0269849 A1 Lewis, Pub. Date: Oct. 30, 2008

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[3]

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[4]

Armstrong, How sun exposure causes skin cancer: An epidemiological perspective, In: Hill D, Elwood JM, English DR

B. Armstrong, How sun exposure causes skin cancer: An epidemiological perspective, In: Hill D, Elwood JM, English DR. Prevention of Skin Cancer. Dordrecht, Nether- lands: Kluwer Academic Publishers, pp. 89-116, 2004

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Johns Hopkins Medicine, Dehydra- tion and Heat Stroke, On-line address: https://www.google.com/amp/s/www.hopkinsmedicine.org/ health/conditions-and-diseases/dehydration-and-heat- stroke%3famp=true, accessed: May 30, 2019

work page 2019
[6]

Slusher, L

T. Slusher, L. Day, T. Ogundele, N. Woolﬁeld, and J. Owa, Filtered sunlight, solar powered phototherapy and other strategies for managing neonatal jaundice in low-resource settings, Early Human Development, pp. 114:11-15, Nov. 2017, doi: 10.1016/j.earlhumdev.2017.09.008. Epub 2017 Sep 15

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[8]

Chang, J

Y . Chang, J. Hwang, H. Kwon, C. Choi, S. Ko, W. Park, S. Shin, and M. Lee, In vitro and in vivo Efﬁcacy of New Blue Light Emitting Diode Phototherapy Compared to Conventional Halogen Quartz Phototherapy for Neonatal Jaundice, J Korean Med Sci, vol. 20, pp. 61-64, 2005

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E. Waltz, Light-Up Pajamas to Treat Babies With Jaundice - Optical ﬁbers woven into fabric makes phototherapy treatment comfy and portable, On-line Biomedical Devices, Nov 8, 2017, https://www.google.com/amp/s/spectrum.ieee.org/the- human- os/biomedical/devices/lightup-pajamas...

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H. Vreman, R. Wong, D. Stevenson, Phototherapy: current methods and future directions, Seminars Perinat, vol. 28, pp. 326-33, 2004

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Pith tools

Reviewed August 14, 2026 · model on record in the stance chip above.

[1] [13]

Bagunu, M

V . Bagunu, M. Perez, Comparative study of Prototype Low- Cost Light Emitting Diode Phototherapy Device versus Conventional Fluorescent Phototherapy in the Treatment of Indirect Hyperbilirubinemia among Term Infants in a Tertiary Government Hospital, submitted to Philippine Pe- diatric Society, unpublished, 2018

work page 2018

[2] [1]

Henny-Harry and H

C. Henny-Harry and H. Trotman, Epidemiology of Neonatal Jaundice at the University Hospital of the West Indies, The West Indian Medical Journal, vol. 61(1), pp. 37-42, 2012

work page 2012

[3] [2]

Lewis, Temporal Control in Phototherapy, United States Patent Application Publication, Pub

C. Lewis, Temporal Control in Phototherapy, United States Patent Application Publication, Pub. No.: US 2008/0269849 A1 Lewis, Pub. Date: Oct. 30, 2008

work page 2008

[4] [3]

87(2), pp

The International Commission on Non-Ionizing Radiation Protection, ICNIRP Guidelines on limits of exposure to ultraviolet radiation of wavelengths between 180 nm and 400 nm (incoherent optical radiation), Health Physics, vol. 87(2), pp. 171-186, 2004

work page 2004

[5] [4]

Armstrong, How sun exposure causes skin cancer: An epidemiological perspective, In: Hill D, Elwood JM, English DR

B. Armstrong, How sun exposure causes skin cancer: An epidemiological perspective, In: Hill D, Elwood JM, English DR. Prevention of Skin Cancer. Dordrecht, Nether- lands: Kluwer Academic Publishers, pp. 89-116, 2004

work page 2004

[6] [5]

Johns Hopkins Medicine, Dehydra- tion and Heat Stroke, On-line address: https://www.google.com/amp/s/www.hopkinsmedicine.org/ health/conditions-and-diseases/dehydration-and-heat- stroke%3famp=true, accessed: May 30, 2019

work page 2019

[7] [6]

Slusher, L

T. Slusher, L. Day, T. Ogundele, N. Woolﬁeld, and J. Owa, Filtered sunlight, solar powered phototherapy and other strategies for managing neonatal jaundice in low-resource settings, Early Human Development, pp. 114:11-15, Nov. 2017, doi: 10.1016/j.earlhumdev.2017.09.008. Epub 2017 Sep 15

work page doi:10.1016/j.earlhumdev.2017.09.008 2017

[8] [7]

Managing Newborn Hyperbilirubinemia and Preventing Kernicterus, Progeny, V olume XX1X, No 1, June 2013, available in http://www.idph.state.ia.us/hpcdp/common/pdf/perinatal newsletters /progeny june2013.pdf

work page 2013