RU216562U1 - FINGER SWEET INDICATOR - Google Patents

Abstract

The utility model relates to devices for functional diagnostics and is intended for assessing the degree of sweating on a five-point system, with fixing the presence of the electrical resistance value of the skin area. The Finger Sweat Indicator (IPPR) can be used to control the sweating of the fingers of the working personnel before assembling precision mechanics devices. Finger sweating indicator containing a power source, a microcontroller based on an 8-bit ATmega 328P chip responsible for the computing process, a switch, a constant resistor, a sensor, which is two spring-loaded metal contacts made of polished medical stainless steel connected in a single plastic case, due to which provides a uniform distribution of pressing the sensor contacts to the skin of the fingers, a digital indicator on the LCD display, which serves to display the degree of perspiration on a five-point system and the resistance of the skin. The power supply supplies voltage through a switch to the microcontroller, which is connected to the LCD. A resistor and a sensor are connected to the outputs of the microcontroller. In the standby mode of pressing the sensor, the voltage at the input pin of the microcontroller does not change. When you press the sensor, the voltage increases at the input pin of the microcontroller. The program stored in the memory of the microcontroller calculates the perspiration score and skin resistance of the finger from the voltage values and displays them on the LCD display.

Description

The utility model relates to medical equipment, namely to devices for functional diagnostics, and is intended for assessing the degree of sweating on a five-point system, with fixing the presence of the electrical resistance value of the skin area, and can be used in the field of medicine, veterinary medicine, hygiene and other areas of meeting vital needs person.

Finger sweating indicator (IPPR) can be used to control the sweating of the fingers of working personnel before assembling precision mechanics devices.

Known "Surface pulse current meter" (RU 69394 U1 dated 09/06/2007), containing input push contacts, DC voltage source, current meter (ammeter) and resistors. The meter is equipped with a step-up transformer with windings, a rectifier in the form of a diode bridge and a sinusoidal voltage transistor generator based on a T1-KT858A type transistor.

The disadvantages of this meter are the lack of accuracy due to the use of a 9 V power supply, the discharge of which causes a significant measurement error. Also, the above-described meter is not suitable for assessing the degree of perspiration of a small area of the skin, namely the fingers, because it does not provide a uniform distribution of pressing to the fingers.

The objective of the utility model is to create a simple and compact solution, and at the same time increase the measurement accuracy, functionality and reliability of the circuit and design.

The task is achieved by the fact that the technical solution uses a digital computing device, a microcontroller, with a modular principle of building an internal architecture, containing an analog-to-digital conversion module and peripheral modules for connecting external devices, made using integrated circuit technologies with a high degree of integration, which allows you to vary functionality in a wide range, changing only the program of work, while increasing the simplicity and compactness of the electronic circuit design, simplifies maintainability, significantly reduces the measurement error and does not require periodic calibration.

In FIG. 1 shows a block diagram of the IPPR, containing

1 - power supply;

2 - switch;

3 - sensor;

4 - constant resistor;

5 - microcontroller;

6 - digital indicator.

The positive polarity output of the power supply (1) is connected to the first output of the switch (2), and the negative polarity output is connected to the first output of the constant resistor (4) and to the negative polarity power supply outputs of the microcontroller (5) and digital indicator (6). Positive power supply outputs of the microcontroller (5) and digital indicator (6) and the first output of the sensor (3) are connected to the second output of the switch (2). The second output of the sensor (3) is connected to the second output of the fixed resistor (4) and the analog input of the analog-to-digital converter of the microcontroller (5). The output pins of the results of the microcontroller (5) are respectively connected to the data input pins of the digital indicator (6).

In FIG. 2 shows a schematic diagram of the IPPR, which is an example of the implementation of a structural diagram in which the following are applied:

power supply (1), made in the form of a 220 V power supply with a constant output voltage of 5 V;

switch (2);

sensor (3), which is two spring-loaded metal contacts made of polished medical stainless steel connected in a single plastic case, due to which a uniform distribution of pressing the sensor contacts to the skin of the fingers is ensured. The relatively large contact area of the sensor (3) with the skin and the remoteness of one contact from another contributes to the measurement of surface resistance, both dry and wet skin;

fixed resistor (4), the value of the electrical resistance of which is selected as 240 kOhm, based on the fact that the value of the constant electrical resistance is recommended to be chosen closer to the desired one;

a microcontroller (5) that performs measuring, computing, analytical processes and displaying the displayed results, based on an 8-bit ATmega 328P chip;

a digital indicator (6) displaying the output results is made on an LCD display that serves to display the degree of perspiration of the fingers on a five-point system and the resistance of the skin, allowing you to simultaneously display up to 80 characters (4 lines of 20 characters each). The display is equipped with a backlight, the brightness of which can be controlled.

In the schematic diagram of Fig. 2, the power supply is connected to a switch through which voltage is applied to terminals 7 and 8 of the microcontroller. Pin 10 of the microcontroller is connected to the first pin of the resistor and to the power pin 14 of the digital indicator of negative polarity, and pin 9 of the microcontroller is connected to the second pin of the resistor and to the first pin of the sensor. The second output of the sensor is connected to the 11th output of the microcontroller and to the power output 15 of the digital indicator of positive polarity. The output terminals 12, 13 of the microcontroller, which are used to transmit the measurement results, are respectively connected to the data input terminals 6, 5 of the digital indicator.

The score corresponds to the requirements of clause 8.6 of OST 92-0069-86, which shows the ratio of the score to the degree of sweating of the skin. IPPR determines the resistance of the skin area: at least 1 MΩ as 1 point, from 300 kΩ to 1 MΩ - 2 points, from 100 kΩ to 300 kΩ -3 points, from 30 kΩ to 100 kΩ - 4 points, less than 30 kΩ - 5 points .

In the IPPR, a more compact model was used, consisting of a display to display the measurement results, a microcontroller with input power and a constant voltage at the output of 5 V, a resistor that sets the range of measured values of the resistance of the finger area. This electrical circuit does not contain elements that interfere with the measurement. The measurement takes place on only one finger of the hand. Due to the optimally selected sensor contact area, made of polished medical stainless steel with a spring-loaded base, it allows you to take readings with a smaller error, which reduces the likelihood of erroneous measurements.

IPPR works as follows

When the switch (2) is turned on from the power source (1), the power supply voltage is applied to the IPS circuit. The circuit is ready for operation immediately after the supply voltage is applied. In the initial state in the standby mode until the skin is pressed against the sensor contacts (3), the sensor resistance has the value of open contacts (more than 20 MΩ), and the voltage drop across the resistor (4), the voltage values at pin 9 and 10 of the microcontroller (5) do not change and equal to 0 V. When you press your finger on the sensor contacts (3), the voltage value at the input terminal (9) of the microcontroller (5) increases in inverse proportion to the resistance value of the skin area of the finger between the sensor contacts, due to the formation of an electrical circuit of a resistive voltage divider resistor (4) - sensor resistance (3). When the sensor contacts are closed, the voltage values at pins 9 and 11 of the microcontroller (5) are equal to the supply voltage value of 5 V. The program in the memory of the microcontroller (5) measures the voltage at pin 9 and processes the measured values, calculates the resistance of the finger skin area, and, based on the result, determines sweating score, which displays on the LCD (6). The microcontroller according to the program performs the required number of calculations, which are averaged, which leads to a decrease in errors and more accurate measurements. Initially, 300 calculations are installed on the microcontroller, if necessary, you can set any number of calculations. Depending on the amount of memory of the microcontroller, its model and the capabilities of the digital indicator (display), the program can carry out a variety of methods for determining the condition of other skin areas, at different times, in other conditions, draw analytical conclusions in the relevant aspect about the human condition and display the necessary information in a variety of ways. forms.

The technical result is the construction of a finger sweating indicator according to a simple, reliable and compact circuit that does not require adjustment, adjustment and routine actions, the functionality and measurement accuracy of which depend on the work program recorded in the microcontroller and on the capabilities of the digital indicator, and the simplicity of the circuit allows it to be operated in a simple, compact, functional and reliable design.

Claims (1)

Finger sweating indicator, containing a power source, a switch, a sensor, a constant resistor, and the positive polarity output of the power source is connected to the first output of the switch, and the negative polarity output is connected to the first output of the constant resistor, characterized in that a digital indicator and a microcontroller with a modular the principle of building an internal architecture, containing an analog-to-digital conversion module and peripheral modules for connecting external devices, made using integrated circuit technologies with a high degree of integration, and the sensor is two spring-loaded metal contacts made of polished medical stainless steel connected in a single plastic case, power leads microcontroller and digital indicator of negative polarity are connected to the output of the negative polarity of the power supply, and the power supply outputs of the positive polarity of the microcontroller and digital indicator and the first output of the sensor are connected s with the second output of the switch, the second output of the sensor is connected to the second output of the constant resistor and the analog input of the analog-to-digital converter of the microcontroller, the output outputs of the results of the microcontroller are respectively connected to the data input terminals of the digital indicator.

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