ES2802816A1 - THERMOSENSIMETER AND METHOD OF MEASURING THERMAL SENSATION THROUGH LINEAR THERMAL GRADIENT. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Thermosensing meter and thermal sensation measurement method using a linear thermal gradient. The present invention describes a device that makes it possible to measure the thermal sensation that a subject experiences when faced with different stimuli. Until now, it had only been possible to measure thermal perception qualitatively using measurement methods that present difficulties. The present invention describes a novel method and device to quantify the thermal sensations of a subject and makes it possible to know how the subject interprets the thermal sensation that he experiences and how he conceptualizes the physical magnitudes linked to this sensation. For this, measures are taken that link neuroreceptive data and statements of the subject about these thermal concepts so that it is possible to quantify the perception of temperature by collecting data continuously, eliminating subjectivity and allowing to establish a link between different variables such as sensations, verbalizations and scales quantitative and qualitative. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Thermosensing meter and thermal sensation measurement method using linear thermal gradient

TECHNICAL SECTOR

The present invention falls within the sector of devices for the detection and measurement of variables by interaction with a subject. More specifically, it refers to a device that makes it possible to measure the thermal sensation that a subject experiences when faced with different stimuli.

BACKGROUND OF THE INVENTION

The perception of temperature is one of the basic mechanisms of the somatosensory system and its functioning is essential since variations of a few degrees can greatly affect the chemical and physiological processes of the organism and, therefore, its survival.

In the case of humans, temperature variations activate a very large number of behaviors that go beyond the merely physiological (shivering, sweating, etc.), giving rise to adaptive behaviors (hiding from the sun, sheltering, etc.) and actions more complex such as changing the temperature of the environment (making a fire or turning on the air conditioning, for example).

These behaviors are the expression of a cognitive process that seems to imply the existence of a mental representation or conceptualization of the processes of cold, heat and temperature (Ezquerra, A. and Ezquerra-Romano, I. From thermosensation to the concepts of heat and temperature : a possible neuroscientific component. EURASIA Journal of Mathematics, Science and Technology Education (2018), 14 (2), 1-11). Said conceptualizations develop in a sequence called conceptual trajectory and comprise a progression in the understanding of concepts through successive learning arranged in sequences; The concepts at each stage of the conceptual trajectory are called alternative conceptions , spontaneous ideas or conceptual errors and have three common characteristics: universality, resistance and persistence. These features suggest that there is a mechanism underlying sensory common to all human beings which, according to some lines of research, is due to the functioning and development of the sensory system. The way in which each sense collects information from outside and processes it, thus shaping or generating alternative conceptions. But alternative conceptions not only have their origin in the interpretation of sensations but also in the same ambiguity or indeterminacy of the sensory systems (Kubricht, JR, Holyoak, KJ, and Lu, H. Intuitive physics: current research and controversies. Trends in Cognitive Sciences (2017), 21 (10), 749-759. Https://doi.org/10.1016Zj.tics.2017.06.002)

In the case of the thermosensor system, until now, studies have been developed on alternative conceptions based on the way we perceive, their characteristics have been analyzed and the way in which their evolution occurs with respect to perceptions (Ezquerra-Romano, I. and Ezquerra, A. Highway to thermosensation: a traced review, from the proteins to de brain. Reviews in the Neurosciences (2017), 28 (1), 41-47: Bokiniec, P. et al. The neural circuits of thermal perception. Current Opinion in Neurobiology (2018), 52: 98-106).

However, it has not yet been possible to interpret the perception of temperature as a result of the interaction of our organism with physical magnitudes, and it has not been possible to study alternative conceptions based on measurable neurophysiological factors. It has only been possible to measure thermal perception qualitatively (for example, those described in documents US2016 / 0374606 and US2019 / 0278374) using measurement methods that present the following difficulties:

- Thermal perception is felt continuously when, in reality, there is a sensitive fragmentation from the neurophysiological point of view.

- Thermal perception is verbalized as an ordered qualitative scale, which causes a lot of information to be lost.

- The categories / words used have emotional and sociocultural components or aspects, and seem strongly dependent on individual issues and personal situation.

- It is difficult to ensure that the terms used by each individual are used by all in the same way to define the same perceptions. That is, an individual may differ from others when performing an assignment between terms and perception, something difficult to control and that prevents establishing reliable links from higher cognitive levels to lower levels or sensor mechanisms.

Therefore, it would be desirable to have a measurement method capable of quantifying the perception of temperature by collecting data continuously, eliminating subjectivity and allowing to establish a link between different variables such as sensations, verbalizations and quantitative and qualitative scales.

EXPLANATION OF THE INVENTION

The present invention describes a novel device to quantify the thermal sensations of a subject and makes it possible to know how the subject interprets the thermal sensation that he experiences and how he conceptualizes the physical magnitudes linked to this sensation. To do this, it takes measures that link neuroreceptive data and statements from the subject about these thermal concepts.

The device comprises an element that generates thermal sensations and a system for capturing the physiological, perceptual and conceptual variables of the individual.

The determination of the thermal sensations is carried out by means of a work profile that generates a temperature gradient to be able to offer those sensations in a tactile way. The extremes of this temperature gradient lie within the limits of nociception (non-harmful perception). The sensation capture system is a signal collection element that, when touched by the subject, indicates to the system the exact point where it has felt a thermal sensation similar to that of the object-problem. Likewise, the device can measure the reaction time (by subtracting the instant of presentation of the problem-object and the instant of capture of the sensation signal); qualitative estimation (through a keypad - real or on a computer screen - with the qualitative temperature scale); the quantitative estimation of the subject (through a keypad —real or on a computer screen— with the quantitative temperature scale) and the degree of confidence that the subject assigns to their responses (through a keypad —real or on a computer screen. computer - with the confidence level scale).

Since the subject must feel different scenarios related to temperature in vivo , the device integrates an interactivity system with the subject to collect their responses. Specifically, the device allows the subject to be exposed to different thermal stimuli: different and / or variable temperatures, in different parts of the body, materials with different conductivities or thermal properties, different environmental conditions, etc. The subject touches the problem-object and indicates a response.

The device has:

- A support (100) formed by a heat insulating material.

- A working profile that is a good thermal conductor, which is located on the support (107).

- Two Peltier plates (103) common in electronics that are placed on the working profile.

- A plastic variable resistor (105) with tactile operation that constitutes the element for collecting the signal when touched by the individual.

- An Arduino Uno (101) device attached to the fully programmable work profile.

- A temperature sensor module (102) also connected to an input of the Arduino.

- A power supply for the peltier plates (106)

- Resistive elements for control and signal adjustment (104).

- A variable set of buttons (B1, B2, B3), with resistances between 1kQ and 1MQ, to digitally collect the information on the qualitative, quantitative and confidence estimation (108).

- An element for assembling the circuits with Arduino or breadboard.

The dimensions of the working profile can be modified in order to guarantee the linearity of the thermal gradient generated. This dimension adjustment is achieved with small extra extensions of mass (of conductive or insulating material) at the appropriate points to force or prevent heat dissipation. This is to avoid areas of overheating or cooling. These extensions are attached to the work profile by means of supports, screws or any other means that facilitate heat exchange.

Peltier plates are devices made up of numerous small joints between two metal alloys that, before the passage of electric current, are capable of establishing an equilibrium heat flow; that is, on the one hand, it heats up and, on the other, it cools. To achieve the temperature gradient, the working profile is heated through the end of a plate. At the other end, the other plate is placed turned over with respect to the first one or in the same orientation, but changing the polarity (the direction of the heat flow changes), cooling the other end of the profile. To improve contact, you can also use a thermal paste that facilitates heat exchange between electronic elements. The plates used in the prototype operate in a range up to 4.7 V and 4 A, and limit temperatures of -29 ° C and 79 ° C. The final current with which they feed is definitively established after previous tests and calibration with the metal profile in order not to produce overheating, non-linear conditions or lower temperature ranges than expected. Other Peltier plates of similar range and different working currents, higher efficiency or even other advanced materials can be used, but always respecting the range of safe temperatures and the linearity of the generated gradient.

The variable resistor for signal collection, when touched by the subject, cuts the current and indicates to the system the exact point where the individual has felt a thermal sensation similar to that of the object-problem. This variable resistor is like a potentiometer, in this case, in the form of a membrane with resistive properties. The sensor is powered by the first pin with a given voltage. While the sensor is open the electric current flows without any resistance to the ground. When the sensor is pulsed, a circuit is closed that allows a potential difference to be measured.

The Arduino Uno device is a microcontrolled board with open source code and specifications developed by the Arduino company. The Arduino board is fully programmable from scratch, so that a new electronic system can be created. The board has digital pins that collect information from modules or any electronic device that offers signals in digital format (1/0 - V> 0 / V <0). It also has analog pins in which a quantized reading can be taken in a 10-bit length (offering 1024 possible discrete values from 0V to max. V- and power supply pins at 5V, 3.3V and ground that is not enough to power the boards, so the Arduino connects to a USB-B with which in turn information is received from the board through a text terminal emulating a serial port from a computer on any operating system ( Win, Mac or Linux).

Through the Arduino the reading of the linear sensor is carried out; the sensor is powered by the 5V output and ground, while the linear sensor's measurement pin connects to one of the Arduino's analog inputs. This input will either collect a value between 0 and 1023, or it can be converted to voltage, resistance, etc. Regardless of the units, it is possible to work directly with the input value since the sensor indicates the position in which the pressure that closes the circuit is being exerted and it would only be necessary to calibrate the reading with the corresponding temperature in the metal profile, when be one-dimensionally parallel devices.

The Arduino input is also used for reading a temperature sensor module based on a metal thermocouple.

The final electronic assembly of the device requires only a breadboard for assembling the circuits with Arduino or a board with soldered elements. If the circuit were open, Arduino has a harmonic or oscillating signal, which implies an unwanted signal in the sensor reading, so that when it is not pulsed, its reading is always 0 V and a reading out of range can be assigned.

The design of the device aims to understand how sensations are interpreted and how the physical magnitudes linked to these sensations are conceptualized; Thus, the device makes it possible to link neuroperceptual data and statements about these thermal concepts since it automates the data collection of different dependent variables related to thermal perception, for example, thermal sensation over a temperature gradient, reaction time, estimation qualitative and quantitative of the subject and the degree of confidence that the subject assigns to his answers. In addition, it integrates all these data together and establishes relationships between the neurophysiological variables and the statements that involve the alternative conceptions.

To perform the measurement, once the subject has been informed about the test to be carried out, the following data is collected:

- Stimuli presented (independent variable since they are previously chosen): proposed temperature and characteristics of the material.

- Sensation experienced by allocation (mute) that the individual makes on a thermal gradient generated expressly by the device; this data is collected automatically.

- Perception of temperature expressed qualitatively on a scale of categories; This data is collected and filed automatically and the category scale is a Spanish version of the one proposed by Green (Green, BG et al. Nociceptive sensations evoked from spots in the skin by mild cooling and heating. Pain (2018), 135 (1), 67-73):

MF: very cold

F: cold

N: neutral (neither cold nor hot)

C: hot

MC: very hot

DK / NA: don't know / don't answer

- Perception of temperature expressed in a quantitative way on a numerical scale; This data is also collected and stored automatically and is set as a step of 5 ° C, which allows for fillings of ± 2.5 ° C although it can vary if desired.

- Level of confidence in the previous answers; A Likert-type scale (Lavrakas, PJ Likert Scale. Encyclopedia of survey research methods (2008) Thousand Oaks, CA: Sage Publications, Inc.) is used on the security of the answers given, where the subject chooses between the following options:

(1) Very little confidence

(2) Low confidence

(3) Somewhat trustworthy

(4) Much confidence

so that these responses that express the security or doubts of the subject allow us to assess the ambiguity generated by the thermosensor system and consider the conceptualization difficulties linked to these concepts.

- Response time, also collected automatically by the device.

- Any other possible expression of the subject related to the sensation (such as pain, verbalizations about perception difficulties, etc.) by recording and filing during the subject's exposure to the presented stimuli.

Through these tests, the range of perceptible temperatures can be known without generating damage. Specifically, it is possible to determine the sensitivity that a subject has to different temperatures in the perceptual range, link perceptual sensitivity with conceptions of cold and heat, determine the subject's perception of the characteristics of the object (thermal conductivity) and problems cognitive and educational aspects of this sensitive indeterminacy as well as assessing perceptual detection times for the different temperatures within the perceptual range (which allows, in turn, to establish safety measures).

The device is easily applicable in educational environments to facilitate the teaching-learning process of physical concepts. It is also useful for people of different ages and with different cognitive abilities, for the detection of cognitive or perceptual problems. On the other hand, in the field of thermal comfort, wearable devices are appearing on the market to adapt people's body temperature, which shows the economic interest of innovating in the field of thermal comfort; In this sense, the described device allows to quantify and automate the collection of many variables related to thermal perception, being able to know the comfort standards. The device can also be integrated into robots, making them more sensitive to our thermal needs.

BRIEF DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, a set of drawings is attached as an integral part of said description, in which, with an illustrative and non-limiting nature, the following has been represented following:

Figure 1. Circuit diagram and device connections.

Next, a list of the different elements represented in the figure that is integrated in the invention is provided:

100 = Support made of thermally non-conductive material

101 = Arduino Uno

102 = Thermometer

103 = Peltier plates

104 = Resistors

105 = Linear Sensor / Touch Potentiometer

106 = Power supply

107 = Profile of heat conducting material

108 = Button panel

PREFERRED EMBODIMENT OF THE INVENTION

The present invention is illustrated by the following example, which is not intended to limit its scope.

Example 1.

In a preferred embodiment of the invention, the device consists of a wooden support (100) on which an aluminum working profile (101) with a conductivity o = 37.8 x 106 S / m is placed in isolation, dimensions of 6x1.5x500 mm and that has small extra extensions of mass at the appropriate points to force or prevent heat dissipation, guaranteeing the linearity of the thermal gradient generated. The extensions are attached to the work profile by means of brackets, screws or any other system that allows parts to be attached and removed.

Two Peltier plates (102) TEC1-03104 are placed on the working profile that operate in a range of up to 4.7 V and 4 A with limit temperatures of -29 ° C and 79 ° C; the current with which they are fed is 4.5 V and 1 A. To facilitate a flow of heat Outside of the aluminum (cooling) a heat sink metal profile provided with a 12V fan is placed, thus improving the efficiency of the plates.

The signal collection element is a plastic variable resistor with touch operation SPL0500203 from the SpectraSymbol Softpot series . For the operation of this resistor or potentiometer (103). For its operation, forces or pressures in the membrane of the order of 0.6 to 1.5 Newtons (61 to 153 g) are sufficient. This pressure is similar to what is usually offered on a smartphone touch screen.

To collect the information on the qualitative, quantitative and confidence estimation, a button panel (108) is placed with a variable number of buttons (B1, B2, B3), connected in parallel between the 3.3 V output of the Arduino and a pin analog, each with a different resistance value, closing the circuit with a resistance (104) of 1 MQ through the ground pin. This allows a single input to give a different voltage to the analog input depending on the button pressed. The value of the reading depends on the resistance associated with each button (RB1, RB2, RB3), in such a way that with a range between 1 kü and 1MQ a large number of buttons can be connected to a single input associated with the different scales. and responses to be recorded.

The Arduino (104) is powered by a 9 V battery or through a USB cable with which communications are received from the board through a text terminal emulating a serial port from any computer and on any operating system (Linux, Win or Mac). Through this Arduino the temperature sensor module (105) is read based on a DS18B20 metal thermocouple with a measurement range of -55 ° C to 125 ° C with an error of ± 0.5 ° C. It has three pins, one for power supply with voltage between 3 and 5.5 V, one for ground and a third pin for reading. The reading format is a standard in OneWire electronics (Stoffregen, sf) that directly provides a reading already calibrated and converted into units of ° C by an Arduino digital input pin. This thermometer is valid both for the calibration between metal temperature and sensor reading and for taking the temperature of possible sample objects or problem objects.

For the electronic assembly, two resistors (104) are necessary: one of 4.7 kü for the DS18B20 between the voltage input and the reading pin, and another much higher than 1 MQ for the linear sensor between the voltage input and the reading pin. reading.

Claims (13)

1. Device for measuring the thermal sensations of a subject characterized in that it comprises an element that generates thermal sensations, a system for capturing the physiological, perceptual and conceptual variables of the individual, and a system for interacting with the subject to collect responses. 2. Device for measuring the thermal sensations of a subject, according to claim 1, comprising: - A support (100) formed by a heat insulating material. - A working profile that is a good thermal conductor, which is located on the support (107). - Two Peltier plates (103) common in electronics that are placed on the working profile. - A plastic variable resistor (105) with tactile operation that constitutes the element for collecting the signal when touched by the individual. - An Arduino Uno (101) device attached to the fully programmable work profile. - A temperature sensor module (102) also connected to an input of the Arduino. - A power supply (106) - Resistors (104). - Button panel (108) - An element for assembling the circuits with Arduino or breadboard. 3. Device, according to claims 1 and 2, where the working profile has dimensions that can be modified by means of extra extensions of mass, of conductive or insulating material, at the appropriate points to force or prevent heat dissipation and avoid overheating or cooling. 4. Device, according to previous claims, where the Peltier plates are placed at the ends of the working profile and operate in a limit temperature range of -29 ° C and 79 ° C. 5. Device, according to previous claims, where a thermal paste is incorporated that facilitates heat exchange between electronic elements. 6. Device according to claim 1, comprising: - a wooden support (100) on which an aluminum working profile (107) with a conductivity o = 37.8 x 106 S / m, dimensions of 6x1.5x500 mm and which has small extra extensions of mass at the points adhered to the work profile; - two Peltier plates (103) TEC1-03104 placed on the working profile that operate in a range of up to 4.7 V and 4 A with limit temperatures of -29 ° C and 79 ° C; the current with which they are supplied is 4.5 V and 1 A through a power supply (106); - a metal heat sink profile provided with a 12V fan, thus improving the efficiency of the boards - a plastic variable resistor with touch operation SPL0500203 from the SpectraSymbol Softpot series as a signal collection element. For the operation of this resistor or potentiometer (105). - an Arduino (101) that is powered with a 9 V battery or through a USB cable that performs the reading of the temperature sensor module (102) based on a DS18B20 metal thermocouple with a measurement range of -55 ° C to 125 ° C with an error of ± 0.5 ° C; It has three pins, one for power supply with voltage between 3 and 5.5 V, one for ground and a third pin for reading. - two resistors (104) for the electronic assembly: one of 4.7 kü for the DS18B20 between the voltage input and the reading pin, and another much higher of 1 MQ for the linear sensor between the voltage input and the reading pin 7. Method for measuring the thermal sensations of a subject using a linear thermal gradient characterized in that it takes measurements that link neuroreceptive data and the subject's statements on these thermal concepts by collecting the following data: - Stimuli presented: temperature and characteristics of the material. - Sensation experienced by allocation (mute) that the individual makes on a thermal gradient generated expressly by the device; this data is collected automatically. - Perception of temperature expressed qualitatively on a scale of categories - Perception of temperature expressed quantitatively on a numerical scale - Level of confidence in the previous answers. - Response time, also collected automatically by the device. - Any other possible expression of the subject related to the sensation (such as pain, verbalizations about perception difficulties, etc.) by recording and filing during the subject's exposure to the presented stimuli. 8. Method for measuring the thermal sensations of a subject, according to claim 7, where the category scale to measure the qualitative perception of temperature is a version of the Green scale: MF: very cold F: cold N: neutral (neither cold nor hot) C: hot MC: very hot DK / NA: don't know / don't answer 9. Method of measuring the thermal sensations of a subject, according to claim 7, where the scale of categories to measure the quantitative perception of temperature is a numerical scale that is proposed as a step of 5 ° C, which allows some landings ± 2.5 ° C although it can vary if desired. 10. Method for measuring the thermal sensations of a subject, according to claim 7, where the confidence level of the responses is calculated using a Likert-type scale that includes the following options: (1) Very little confidence (2) Low confidence (3) Somewhat trustworthy (4) Much confidence so that these responses that express the security or doubts of the subject allow us to assess the ambiguity generated by the thermosensor system and consider the conceptualization difficulties linked to these concepts. 11. Use of the claimed device in the teaching-learning process of physical concepts. 12. Use of the claimed device for the detection of cognitive or perceptual problems. 13. Use of the claimed device integrated into another device or robot.