New Magnetic Temperature Non-Contact Sensor

Dima Cheskis; Eddy Divin Kenvo Songwa

REVIEW 4 major objections 5 minor 16 references

New Magnetic Temperature Non-Contact Sensor

T0 review · 4 major / 5 minor · reviewed 2026-08-07 · deepseek-v4-flash

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Pith's one-line read A bimetal strip inside a closed nonmagnetic container can signal its temperature to an external Hall sensor through the wall, the paper argues, based on a linear voltage–temperature calibration measured during cooling in air.

desk verdict A sensible prototype with a clear physical mechanism, but the data are far too thin to support the fluid-in-container claim; the wall tests actually undercut it. read the letter →

arxiv 2506.07512 v1 pith:YTCVPDME submitted 2025-06-09 physics.app-ph

Eddy Divin Kenvo Songwa , Dima Cheskis This is my paper

classification physics.app-ph

keywords TemperaturesensorMagneticNon-contactHallBimetalstripWaterboilerNonmagneticcontainerContactlessmeasurement

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 claims that temperature inside a closed nonmagnetic container can be read from outside by converting heat into motion. A bimetal strip fixed inside the container bends as the fluid warms, moving a magnetized free end relative to a Hall sensor mounted on the wall; the changing magnetic field gives a voltage that tracks temperature. The supporting measurement is a single cooling run in air in which Hall voltage and strip temperature show a linear relationship. Wall tests indicate steel distorts the magnetic response badly while aluminum transmits it better, but the authors did not test with any fluid inside the container. If the strip's deflection stays calibrated through the wall, the design offers a non-contact alternative where infrared and acoustic methods cannot see the liquid.

What carries the argument

The load-bearing mechanism is the bimetal strip as a temperature-to-displacement transducer inside the container, coupled magnetically to an external Hall sensor. One end of the strip is clamped to the wall; the free end is magnetized by a permanent magnet, and as the strip bends with temperature the distance between that magnetized end and the Hall sensor changes, modulating the measured field. The paper's argument rests on the resulting Hall voltage being a repeatable, approximately linear function of strip temperature, which in the air test it is.

What would settle it

Fill a nonmagnetic container with water, seal the bimetal strip inside, and record Hall voltage against a calibrated thermometer while the water is heated and cooled over the intended range; any hysteresis, drift, or deviation of the Hall-voltage-versus-temperature curve from the air calibration would disprove the claimed suitability.

Watch

Extended reading notes

Core claim

The central discovery is that a Hall sensor outside a container can detect the temperature-dependent deflection of a bimetal strip inside it: as the strip cools from 40 °C in air, the Hall voltage rises in a near-linear fashion with falling strip temperature, establishing a calibration curve. The authors interpret this linearity as proof of principle that the same arrangement can measure fluid temperature in a closed nonmagnetic vessel, with the strip clamped inside and the magnet–Hall assembly outside. They further report that a steel wall severely weakens the magnetic response, while an aluminum wall preserves the magnetic signal but introduces stronger nonlinearity in the temperature relation. The paper's stated conclusion is that the sensor is suitable for fluids in nonmagnetic containers, with corrosion resistance of the strip named as the main obstacle to practical boiler use.

Load-bearing premise

A Hall voltage measured outside a container is a reliable stand-in for the temperature of a fluid inside it: the strip must reach the fluid temperature, its bending must repeat the same way every time, and the wall must not distort the magnetic signal.

Editorial extensions

If this is right

A boiler equipped with this sensor can monitor water temperature from outside the vessel, avoiding pipe drilling and the risk of leaks.
Steel walls are effectively ruled out for this DC magnetic readout, since the ferromagnetic wall weakens and distorts the response; nonmagnetic walls such as aluminum preserve the signal.
Aluminum walls transmit the magnetic signal but produce a nonlinear temperature response, so a practical instrument would need a calibrated curve instead of the simple linear fit.
Deployment in water requires protecting the bimetal strip against corrosion and oxidation; the paper names this as the main condition for the sensor to work in practice.
The current proof covers a single cooling run from 40 °C in air, so the operating envelope and repeatability under cycling remain open engineering questions.

Reading between the lines

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

A natural next experiment would place the strip inside a water-filled nonmagnetic container and compare Hall-derived temperature with a reference probe over repeated heating–cooling cycles; this would reveal whether the wall introduces hysteresis or lag that the air calibration misses.
The magneto-mechanical readout is not tied to bimetal strips specifically; other temperature-driven moving elements, such as shape-memory actuators, could be substituted while keeping the same external Hall detector.
For ferromagnetic walls, the paper's steel test hints that DC magnetometry is the weak link; an AC modulation or flux-guide arrangement might recover the signal, but that is a design step the paper does not take.
A fatigue test measuring Hall-voltage drift after many thermal cycles would establish a maintenance interval for boiler use, since the strip's spring constant could change with repeated bending.

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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

Short version: the idea is clever and the first measurement is promising, but the paper's central claim is not supported by the evidence it presents. The single air cooldown curve cannot carry the weight of "suitable for fluids inside nonmagnetic containers," and the paper's own wall tests make that claim harder to believe, not easier.

What's genuinely new: a bimetallic strip inside a container, magnetized by an external permanent magnet, with a Hall sensor outside reading deflection as a temperature proxy. That's a reasonable combination of mature parts, and the reported Hall-voltage-versus-temperature curve during one cooldown is plausibly linear. The measurements are simple and reproducible in principle. The authors also deserve credit for explicitly listing practical concerns (corrosion, oxidation, insulation, cycling) as future work. The self-citations to their own low-current Hall sensor work are relevant background, not an attempt to inflate.

The soft spots are real and they are load-bearing. There is one cooldown run, no error bars, no repeatability, no calibration against a reference, and no fluid inside the test container. The wall tests, which are meant to demonstrate applicability, show nonlinear external-versus-internal temperature relations for both steel and aluminum. The authors interpret these as acceptable, but the linear fit from Figure 6 is the calibration that converts Hall voltage to temperature. If the wall shifts that relationship nonlinearly, the calibration no longer holds. Without a measurement using an actual fluid and a wall, the claim that the sensor can measure fluid temperature inside a boiler is an assertion, not a result. The linear fit to the same data that are used to demonstrate linearity is also not an independent test; it is a calibration curve.

That said, this is not a sloppy or incoherent paper. It reads like an honest progress report. The mechanism is physically sound, and the first air measurement is a legitimate starting point. The failure is in the leap from that starting point to the conclusion.

Who is this for? Someone working on non-invasive temperature sensing for sealed vessels might find the concept worth a quick read. But as a paper, it needs more data before it can be taken as a demonstration. I would not send it to a journal as-is; a serious referee would need substantially more characterization. My recommendation: treat it as a working note, not a citable result. If the authors extend it with repeated runs, fluids, walls, and error analysis, the idea could become a real sensor. For now, the central claim is unsupported.

Desk decision: reject, but with the door open for a revised version with proper characterization.

Referee Report

4 major / 5 minor

Summary. The manuscript proposes a non-contact temperature sensor for fluids inside nonmagnetic containers. A bimetal strip placed inside the container bends with temperature, and a permanent magnet plus a Hall sensor placed outside detect the resulting change in the magnetic field. The authors report a single cooldown measurement of a bare bimetal strip in air, showing a roughly linear relation between Hall voltage and temperature (Fig. 6), and two tests of steel and aluminum wall response (Figs. 7-8). They conclude that the sensor is suitable for measuring the temperature of fluids within nonmagnetic containers.

Significance. If fully demonstrated, such a sensor would address a real need: sealed nonmagnetic containers where optical access is unavailable. The operating principle is simple and inexpensive, and the simultaneous measurement of temperature and Hall voltage in Fig. 5 is a reasonable first step. The paper also candidly lists several durability considerations, which is appropriate for a prototype report. However, the current evidence is only preliminary: one air cooldown, no fluid, no repeatability, no uncertainty analysis, and unquantified wall nonlinearities. The significance of the contribution is therefore not yet established, and the conclusions in the abstract and Section 5 substantially overstate what the data support.

major comments (4)

[§3, §4, Fig. 6] The central calibration is based on a single cooldown run of a bare bimetal strip in air, with no repeated trials, no error bars, and no reported regression statistics (slope, intercept, R²). The claim of a "linear relationship" is asserted from inspection of a scatter plot; this is not sufficient to establish a reproducible sensor response, especially because the same dataset is used both to infer and to demonstrate the linearity.
[§4, Figs. 7-8, §5] The conclusion that the sensor is suitable for nonmagnetic containers is not supported by the wall tests. For steel the external-internal temperature response is described as "not highly linear," and for aluminum the nonlinearity is "even more pronounced." No quantitative measure of the nonlinearity, no calibration or correction procedure for the wall, and no test with an actual container wall together with the Hall sensor are provided. The claim in Section 5 therefore does not follow from the reported measurements.
[§3, §4] No measurement with an actual fluid is reported. The abstract and conclusion claim fluid temperature measurement, but the only temperature measured is that of the bimetal strip in air using a thermocouple. The wall tests compare only external and internal temperatures during cooling with no fluid present; they do not show that the bimetal strip reaches the temperature of a surrounding fluid, nor that a wall preserves the Hall-voltage-to-temperature relation measured in Fig. 6. A fluid-filled container experiment, or at least a quantitative thermal model, is required before the central claim can be justified.
[§1, §2] The description of the operating principle is qualitative: the manuscript does not specify the bimetal strip's dimensions, material properties, the magnet's geometry, the Hall sensor's sensitivity, or the distance between the strip and the sensor. Without these parameters, the reader cannot assess whether the observed signal is physically consistent with the proposed mechanism or whether the response would remain valid across different container geometries and wall materials.

minor comments (5)

[§4] The list of considerations (corrosion, oxidation, durability, insulation) is appropriate, but it omits the more fundamental issue that no liquid was used in any test; the authors should either add such a test or explicitly state this as a limitation.
[Figs. 7-8] The figure captions say "temperature response of both sides of the cooling process" but do not define which quantities are plotted; please clarify whether these are internal versus external wall temperatures, Hall voltages, or derived ratios, and label the axes and units.
[Fig. 3] The schematic shows a boiler application but no dimensions or scale; adding typical distances would be useful because the Hall sensor output depends strongly on the separation from the bimetal strip.
[§5] The conclusion repeats the abstract claim verbatim; it should be tempered to "preliminary results suggest the sensor may be suitable" given the limited experimental basis.
[References] Several references are self-citations (e.g., [15] and [16]) and are not directly about temperature measurement; consider adding references on bimetal actuator modeling and on non-contact temperature sensing in sealed containers.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the Hall-voltage/temperature relation is a calibration fit to the measured cooldown data, and the self-citations are background hardware references, not load-bearing inputs to the temperature response.

full rationale

The paper's chain is: a bimetal strip bends with temperature; a magnetized strip changes the Hall voltage; a simultaneous cooldown measurement yields a linear Hall-voltage vs. temperature relation (Fig. 6); separate wall tests characterize steel and aluminum (Figs. 7 and 8); and the conclusion claims suitability for fluids in nonmagnetic containers. None of these steps reduces by construction to its own input. The Fig. 6 linear relation is a fit to the same cooldown data, but the paper does not present a held-out prediction or validate the sensor by comparing a predicted temperature to an independently measured fluid temperature. Instead, it uses the observed correlation as evidence of viability. That is an in-sample demonstration, not a circular derivation. The self-citations [15,16] concern a low-current Hall sensor circuit and are used only as hardware background; the temperature response is not imported from those papers. The wall tests are separate measurements, not logically forced by the calibration, and their nonlinearity actually undermines the conclusion, which is an evidential/correctness problem rather than circularity. Under the standard that circularity requires an exhibited reduction of a claimed derivation to its own fitted or self-cited inputs, no such step is present.

Assumptions & free parameters 1 free parameters · 4 assumptions · 0 invented entities

The central claim rests on standard Hall physics, on the assumed monotonic deflection of a bimetallic strip, and on the untested equivalence between strip temperature and fluid temperature. The linear fit is a fitted relationship, not a predictive model, and no independent calibration is provided.

free parameters (1)

Linear fit slope and intercept
A linear regression is fit to the Hall voltage versus temperature data in Figure 6, but the fit parameters, R^2, and residuals are not reported; the fit is used to claim a linear relationship.

assumptions (4)

standard math Hall voltage is proportional to the magnetic field at the sensor.
Standard linear Hall effect model, invoked in Section 2 when describing the Hall sensor.
domain assumption The bimetallic strip's curvature is a monotonic function of temperature over the operating range.
Invoked in Sections 2 and 3; no material data or stress model is provided.
domain assumption The permanent magnet's field and the strip's magnetization are stable during the measurement.
Assumed implicitly in Section 4; the paper notes oxidation could alter magnetic properties, which would break this assumption.
domain assumption The temperature measured by the thermocouple attached to the strip represents the temperature that would be measured in a fluid.
Used in the cooldown experiment in Section 3; no fluid was present, so the equivalence to real fluid temperature is untested.

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Cite this review

Pith. "Pith review of New Magnetic Temperature Non-Contact Sensor." pith.science (2026). https://pith.science/paper/YTCVPDME

@misc{pith2026250607512,
  author       = {Pith},
  title        = {Pith review of: New Magnetic Temperature Non-Contact Sensor},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/YTCVPDME}},
  note         = {Machine review of arXiv:2506.07512}
}

read the original abstract

Non-contact temperature sensors are widely used, often utilizing infrared light for temperature measurement. However, specific applications demand non-contact detection, particularly within closed containers containing fluids or gases, where optical methods are unsuitable. Our approach is designed precisely for this purpose. We conducted measurements, introduced a prototype of our detector, and confirmed its compatibility with nonmagnetic containers.

Figures

Figures reproduced from arXiv: 2506.07512 by the authors.

**Figure 2.** The Hall system [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗

**Figure 3.** The schematic description of water boilers temperature measurements. [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗

Figures from the paper (5 more)

**Figure 4.** Figure 4: The experimental system for non-contact temperature measurement. [PITH_FULL_IMAGE:figures/full_fig_p004_4.png]

**Figure 6.** Figure 6: On the left side of [PITH_FULL_IMAGE:figures/full_fig_p004_6.png]

**Figure 6.** Figure 6: The linear dependence between the magnetic sensor (Hall) voltage and temperature [PITH_FULL_IMAGE:figures/full_fig_p005_6.png]

**Figure 7.** Figure 7: The boiler steel wall temperature response of both sides of the cooling process. [PITH_FULL_IMAGE:figures/full_fig_p006_7.png]

**Figure 8.** Figure 8: The aluminum wall temperature response of both sides of the cooling process. [PITH_FULL_IMAGE:figures/full_fig_p007_8.png]

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Reference graph

Works this paper leans on

16 extracted references · 16 canonical work pages

[1]

Arman Kuzubasoglu and S

B. Arman Kuzubasoglu and S. Kursun Bahadir. Flexible temperature sensors: A review. Sensors and Actuators A: Physical, 315:112282, 2020

work page 2020
[2]

Turkiewicz, M

M. Turkiewicz, M. Gierczak, D. Nowak, P. Markowski, E. Proci´ ow, and A. Dziedzic. Thermocouples, thermopiles and thermoelectric generators on rigid and flexible sub- strates. In42nd International Spring Seminar on Electronics Technology (ISSE), pages 1–6, 2019

work page 2019
[3]

Ara´ ujo

A. Ara´ ujo. Multi-spectral pyrometry—a review.Measurement Science and Technology, 28:82002, 2017. 6 Figure 8: The aluminum wall temperature response of both sides of the cooling process

work page 2017
[4]

Moisello, P

E. Moisello, P. Malcovati, and E. Bonizzoni. Thermal sensors for contactless temperature measurements, occupancy detection, and automatic operation of appliances during the covid-19 pandemic: A review.Micromachines (Basel), 12:148, 2021

work page 2021
[5]

X. Zhou, Q. Tan, X. Liang, B. Lin, T. Guo, and Y. Gan. Novel multilayer saw temper- ature sensor for ultra-high temperature environments.Micromachines (Basel), 12:643, 2021

work page 2021
[6]

Zhao and J

Y. Zhao and J. H. M. Bergmann. Non-contact infrared thermometers and thermal scan- ners for human body temperature monitoring: A systematic review.Sensors (Basel), 23, 2023

work page 2023
[7]

J. S. Haller Jr. Medical thermometry–a short history.Western Journal of Medicine, 142:108, 1985

work page 1985
[8]

Usamentiaga, P

R. Usamentiaga, P. Venegas, J. Guerediaga, L. Vega, J. Molleda, and F. G. Bulnes. Infrared thermography for temperature measurement and non-destructive testing.Sen- sors, 14:12305, 2014

work page 2014

Show all 16 references

[9]

G. K. Balakrishnan, C. T. Yaw, S. P. Koh, T. Abedin, A. A. Raj, S. K. Tiong, and C. P. Chen. A review of infrared thermography for condition-based monitoring in electrical energy: Applications and recommendations.Energies (Basel), 15:6000, 2022

2022
[10]

Zhang, Y

Z. Zhang, Y. Liang, J. Qian, K. Jiang, X. Sun, and L. Huang. Review of the theory and application of infrared thermography in transmission line monitoring and equipment monitoring. InPanda Forum on Power and Energy (PandaFPE), 2023. 7

2023
[11]

Kylili, P

A. Kylili, P. A. Fokaides, P. Christou, and S. A. Kalogirou. Infrared thermography (irt) applications for building diagnostics: A review.Applied Energy, 134:531, 2014

2014
[12]

H. Huan, L. Liu, X. Chen, C. Peng, J. Zhan, Q. Liu, and Y. Yao. An indirect tempera- ture measurement of oil pipelines based on embedded devices.Measurement, 159:107747, 2020

2020
[13]

Maurelli, M

L. Maurelli, M. Mazzoleni, and F. Previdi. Modeling and simulation of bimetallic strips in industrial circuit breakers.IF AC, 54:803, 2021

2021
[14]

Castro, J

H. Castro, J. Galvis, and S. Castro. Automated setup for van der pauw hall measure- ments.IEEE Transactions on Instrumentation and Measurement, 60:198, 2011

2011
[15]

Sharon, B

Y. Sharon, B. Khachatryan, and D. Cheskis. Towards a low current hall effect sensor. Sensors and Actuators A: Physical, 279:278, 2018

2018
[16]

Cheskis, B

D. Cheskis, B. Khachatryan, and Y. Sharon. Low current hall effect sensor. US Patent, February 1986. 8

1986

Pith tools

Reviewed August 7, 2026 · model on record in the stance chip above.

[1] [1]

Arman Kuzubasoglu and S

B. Arman Kuzubasoglu and S. Kursun Bahadir. Flexible temperature sensors: A review. Sensors and Actuators A: Physical, 315:112282, 2020

work page 2020

[2] [2]

Turkiewicz, M

M. Turkiewicz, M. Gierczak, D. Nowak, P. Markowski, E. Proci´ ow, and A. Dziedzic. Thermocouples, thermopiles and thermoelectric generators on rigid and flexible sub- strates. In42nd International Spring Seminar on Electronics Technology (ISSE), pages 1–6, 2019

work page 2019

[3] [3]

Ara´ ujo

A. Ara´ ujo. Multi-spectral pyrometry—a review.Measurement Science and Technology, 28:82002, 2017. 6 Figure 8: The aluminum wall temperature response of both sides of the cooling process

work page 2017

[4] [4]

Moisello, P

E. Moisello, P. Malcovati, and E. Bonizzoni. Thermal sensors for contactless temperature measurements, occupancy detection, and automatic operation of appliances during the covid-19 pandemic: A review.Micromachines (Basel), 12:148, 2021

work page 2021

[5] [5]

X. Zhou, Q. Tan, X. Liang, B. Lin, T. Guo, and Y. Gan. Novel multilayer saw temper- ature sensor for ultra-high temperature environments.Micromachines (Basel), 12:643, 2021

work page 2021

[6] [6]

Zhao and J

Y. Zhao and J. H. M. Bergmann. Non-contact infrared thermometers and thermal scan- ners for human body temperature monitoring: A systematic review.Sensors (Basel), 23, 2023

work page 2023

[7] [7]

J. S. Haller Jr. Medical thermometry–a short history.Western Journal of Medicine, 142:108, 1985

work page 1985

[8] [8]

Usamentiaga, P

R. Usamentiaga, P. Venegas, J. Guerediaga, L. Vega, J. Molleda, and F. G. Bulnes. Infrared thermography for temperature measurement and non-destructive testing.Sen- sors, 14:12305, 2014

work page 2014