CN209878418U - Electrochemical alcohol tester based on high-sensitivity dynamic monitoring breath sampling of pressure sensor - Google Patents

Abstract

The utility model discloses an electrochemistry alcohol tester based on high sensitive dynamic monitoring of pressure sensor breathes breath sampling, include by MCU, power module, display, blow gun, electrochemistry alcohol sensor, alcohol sensor front end processing circuit, pressure sensor response amplifier circuit, exhalation gas passageway are constituteed. The utility model discloses use pressure sensor and response amplifier circuit design on the circuit, make up with electrochemistry alcohol sensor and processing circuit, to the size of exhaling the flow, exhale continuity dynamic monitoring, it is less influenced by ambient temperature to the control expiration time and the expiration volume of intelligence.

Description

Electrochemical alcohol tester based on high-sensitivity dynamic monitoring breath sampling of pressure sensor

Technical Field

The utility model belongs to the technical field of gaseous detection, concretely relates to electrochemistry alcohol tester based on high sensitive dynamic monitoring of pressure sensor breathes out sampling.

Background

The alcohol tester mainly comprises a semiconductor alcohol tester and an electrochemical alcohol tester (also called a fuel cell type alcohol tester), and compared with a semiconductor, the electrochemical alcohol tester has the advantages of high precision, good repeatability and stability, long service life and the like. At present, the civil-grade electrochemical alcohol tester on the market mainly senses the breath sampling by a thermistor or a Hall element.

The thermistor sensing is to install a thermistor in a sensor sensing channel of the alcohol tester, and the functional schematic diagram is shown in figure 1. When a person is tested to exhale, the thermistor senses the temperature during exhalation, taking a negative temperature coefficient as an example, the higher the temperature is, the smaller the thermistor Rt resistor is, the voltage Vout1 on the thermistor is reduced, the curve is shown as the output voltage curve VT of the thermistor sensing the exhalation temperature in fig. 1, and when the VT is rapidly reduced, as the section S1 in fig. 1, the beginning of exhalation is judged; when the VT rises rapidly, as in section S2 of fig. 1, it is determined that exhalation is interrupted. The sensitivity of the thermistor for sensing temperature change at low temperature is high, the sensitivity of the thermistor for sensing temperature change at high temperature is weak, when the temperature is higher than 40 ℃, the sensitivity of the thermistor for sensing temperature change is greatly reduced, the resistance change rate is smaller and smaller, and the change rate of an output voltage curve VT of the thermistor for sensing expiration temperature is smaller. The temperature of human body is about 37 ℃, so the temperature of the gas exhaled from human body is about 34-37 ℃, if the tested environment temperature is about 37 ℃, the environment temperature is almost the same as the exhalation temperature, and the sensitivity of the thermistor for sensing the exhalation is the lowest.

The Hall element works on the principle of Hall effect, the Hall effect applies a magnetic field to the direction that the current of the Hall element forms a positive angle, the Hall element can generate a certain electric potential in the direction of the right angle of the current and the magnetic field, the function schematic diagram is shown in figure 2, a magnet N is arranged in a sensor sensing channel of the alcohol tester, the Hall element is designed on a circuit board which is at a certain distance from the magnet, a spring is arranged in the sensor sensing channel between the magnet N and the Hall element, when no breath exists, the magnet N is separated from the Hall element by the spring, when the breath test is carried out, the magnet N bears the expiratory pressure and compresses the spring, when the magnet N moves to the position of the Hall element, the Hall element senses the magnetic field of the magnet N to generate a certain voltage Vout2, the voltage change curve of the Hall element is as the output voltage curve VH of the Hall element sensing magnetic field of figure 2, when VH, judging the beginning of exhalation as in section S3 of fig. 2; when VH has no output, as in section S4 of fig. 2, it is judged that exhalation is interrupted. However, whether the sensor is a thermistor or a hall element, the presence or absence of the exhalation test can be determined, but the size of the exhalation flow cannot be determined.

The European Union 2012 drafted and formally determined that the standard EN16280 passed in the field of breath alcohol testing devices used by the general public, and the standard stipulates the basic safety, performance requirements and testing methods of alcohol testers, and particularly stipulates that the alcohol testers can monitor the continuity of exhaled air and the volume capacity of the exhaled air so as to accurately reflect the alcohol content in human bodies. According to the requirements of the EN16280 standard: the alcohol tester must be able to monitor the continuity of the expired gas and the volume capacity of the expired gas, and the minimum expired volume is 1.2L, the minimum expired flow is 0.15L/s, and the expiration time is not less than 3 s. When the minimum flow of the expired air is less than 0.15L/s or the expired air is interrupted or the expired air volume does not reach 1.2L due to the expiration time being less than 3s, the alcohol tester must be capable of giving an error prompt and giving no specific test value.

When the expiratory flow is 0.15L/s, the required expiratory time is 1.2L/(0.15L/s) =8 s; according to EN16280 standard, the minimum expiration time is not less than 3s, when the expiration time is 3s, the expiration flow required for expiration of 1.2L of gas volume is 1.2L/3s =0.4L/s, and in summary, when the expiration flow of a test person is equal to 0.15L/s, the minimum expiration time is 8s, when the expiration flow is equal to 0.4L/s, the expiration time is 3s, which is the minimum time specified by EN16280, when the expiration flow is greater than 0.4L/s, the expiration time cannot be less than 3s, which is the minimum time specified by EN16280, when the expiration flow is greater than 0.15L/s and less than 0.4L/s, the expiration time is between 3s and 8 s. The electrochemical alcohol test based on the thermistor and the Hall element can judge the start or the interruption of the expiration test, but because the size of the expiration flow cannot be judged, whether the expiration flow is lower than 0.15L/s or not cannot be judged, and the expiration time cannot be intelligently controlled according to the size of the expiration flow.

Disclosure of Invention

The to-be-solved problem of the utility model is to provide an electrochemistry alcohol tester of high sensitive dynamic monitoring expiration sampling, when alcohol testing, it is very little to be influenced by ambient temperature, effectively judges the size of expiratory flow to the control expiration time and the expiration volume of intelligence make the more accurate reaction of test result human interior alcohol content.

In order to solve the technical problem, the utility model discloses use pressure sensor and response amplifier circuit design on the circuit, combine with electrochemistry alcohol sensor and processing circuit, to the size of expiration flow, expiration continuity dynamic monitoring, thereby intelligent control expiration time and expiration volume pressure sensor can respond to pressure signal, and can convert pressure signal into the signal of telecommunication according to certain law, and sensitivity is high, expiration flow is big more, the signal is big more, otherwise, the signal is little, especially pressure sensor performance receives the temperature influence very little, can both normally work at-40 ℃ ~ +125 ℃, receive environmental impact little.

The utility model provides an electrochemistry alcohol tester based on high sensitive dynamic monitoring of pressure sensor breathes breath sampling, including MCU (1), power module (2), display (3), blow gun (4), electrochemistry alcohol sensor (5), alcohol sensor front end processing circuit (6), exhalation gas passageway (9), electrochemistry alcohol sensor (5) pass through alcohol sensor front end processing circuit (6) with the first collection end ADC1 of MCU (1) is connected, its characterized in that: the pressure acquisition device is characterized by further comprising a pressure sensor (7) and a pressure sensor induction amplifying circuit (8), wherein the pressure sensor (7) is connected with a second acquisition end ADC2 of the MCU (1) through the pressure sensor induction amplifying circuit (8).

Further, the electrochemical alcohol sensor (5) and the pressure sensor (7) are separated by a perforated baffle (10) in the exhaled gas channel (9), and the distance from the perforated baffle (10) to the mouthpiece (4) is 1-2 cm.

The beneficial effects of the utility model reside in that: the design of the microphone and the processing circuit thereof is added on the circuit, and the microphone and the processing circuit thereof are combined with the semiconductor alcohol sensor and the processing circuit thereof, so that the breath flow and the breath continuity are dynamically monitored, the influence of the ambient temperature is small, and the breath time and the breath volume are intelligently controlled.

Drawings

FIG. 1 is a functional schematic diagram of a thermistor-induced alcohol tester.

Fig. 2 is a functional schematic diagram of a hall element induction alcohol tester.

Figure 3 is the utility model discloses based on the high sensitive dynamic monitoring of pressure sensor exhales electrochemical alcohol tester structure function schematic diagram of sampling.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and embodiments.

Embodiment 1 calibration of the electrochemical alcohol tester based on high-sensitivity dynamic monitoring breath sampling of the pressure sensor.

The utility model provides an electrochemistry alcohol tester based on high sensitive dynamic monitoring of pressure sensor breathes out sampling before dispatching from the factory, at first mark minimum expiratory flow be 0.15L/s with minimum expiration time 3s required flow 0.4L/s parameter information when. During calibration, 0.15L/s of expiratory flow generated by a specific device is used for exhaling the mouthpiece (4), the pressure sensor (7) can sense the pressure generated by the expiratory flow instantly to generate a corresponding electric signal, and the electric signal is processed by the pressure sensor sensing amplifying circuit (8) to sense an output voltage curve of the pressure sensor (such as a solid time period T1 of a curve V2 in figure 3). The ADC2 samples the voltage, the ADC value of the voltage is used as a reference value 1 to be recorded and stored in an EEPROM address 1 in the MCU, the mouthpiece (4) is exhaled by using exhalation flow of 0.4L/s, the ADC2 samples the pressure sensor sensing output voltage generated by the pressure sensor, and the ADC value of the voltage is used as a reference value 2 to be recorded and stored in an EEPROM address 2 in the MCU.

The utility model discloses the requirement that factory setting can satisfy EN16280 standard: the alcohol tester must be able to monitor the continuity of the expired gas and the volume capacity of the expired gas, and the minimum expired volume is 1.2L, the minimum expired flow is 0.15L/s, and the expiration time is not less than 3 s. When the flow of the expired air is less than 0.15L/s or the expired air is interrupted or the expired air volume does not reach the requirement of 1.2L because the expiration time is not enough for 3s, the alcohol tester must be capable of giving an error prompt and giving no specific test value.

The minimum expired volume from the lungs is 1.2L according to EN 16280. When the expiratory flow is 0.15L/s, the required expiratory time is 1.2L/(0.15L/s) =8 s; according to EN16280 standard, the minimum expiration time is not less than 3s, when the expiration time is 3s, the expiration flow required for expiration of 1.2L of gas volume is 1.2L/3s =0.4L/s, and in summary, when the expiration flow of a test person is equal to 0.15L/s, the minimum expiration time is 8s, when the expiration flow is equal to 0.4L/s, the expiration time is 3s, which is the minimum time specified by EN16280, when the expiration flow is greater than 0.4L/s, the expiration time cannot be less than 3s, which is the minimum time specified by EN16280, when the expiration flow is greater than 0.15L/s and less than 0.4L/s, the expiration time is between 3s and 8 s.

Embodiment 2 the utility model discloses use of electrochemical alcohol tester based on high sensitive dynamic monitoring breath sampling of pressure sensor.

The utility model discloses externally add the power after, power module (2) give the inside power supply of alcohol tester, and alcohol tester is initialized, and alcohol tester operating condition shows by display (3) with the test result. After the alcohol tester is initialized, when the display (3) prompts that the alcohol tester can test, a tester can perform expiration test on the blowing nozzle (4), expiration gas enters the inside of the tester in two paths through an expiration gas channel (9), one path of the expiration gas enters an alcohol sensor sensing channel, a fuel cell type material in the electrochemical alcohol sensor (5) performs a chemical reaction with the expiration gas, and a generated electric signal is processed by an alcohol sensor front-end processing circuit (6) to generate an alcohol sensor output voltage curve V1; meanwhile, the other path enters a pressure sensor sensing channel, the pressure sensor (7) can sense the pressure generated by the expiratory flow instantly to generate different electric signals, and the electric signals are processed by a pressure sensor sensing amplifying circuit (8) to generate a pressure sensor sensing output voltage curve (as a solid line of a T1 time period of a curve V2 in fig. 3); when the expiratory flow is larger, the expiratory pressure is larger, and the output voltage is also larger (as a dotted line of the T1 time period of the curve V3 in FIG. 3), and conversely, the pressure sensor senses the output voltage to be smaller. A perforated baffle (10) is arranged between the two induction channels for separation, and the distance from the perforated baffle (10) to the blowing nozzle (4) is 1-2 cm.

When the utility model discloses during normal test, ADC2 samples in real time the pressure sensor response output voltage curve and compares with calibration benchmark 1 and benchmark 2 that store in EEPROM, when ADC2 real-time sampling value is less than benchmark 1 that 0.15L/s expiratory flow produced, alcohol tester indicates that the expiration is wrong, no test result is given, when ADC2 real-time sampling value is equal to benchmark 1 that 0.15L/s expiratory flow produced, expiration shortest time is 8s, when ADC2 real-time sampling value is equal to or greater than benchmark 2 that 0.4L/s expiratory flow produced, expiration shortest expiration time is 3s, when ADC2 real-time sampling value is greater than benchmark 1 that 0.15L/s expiratory flow produced and is less than benchmark 2 that 0. 2L/s expiratory flow produced, expiration time is 3s ~ s between a certain appropriate value, for example, 5s is common in expiration test, expiration can not be interrupted, if the pressure sensor response output voltage curve drops down (as figure 3V 466), the pressure sensor responds to the real-time of the pressure sensor output voltage curve, the last the test result of the expiration pressure sensor, the alcohol sensor response voltage curve is accurate, the expiration pressure sensor is judged to the expiration pressure output, the expiration pressure sensor is not enough, the expiration pressure sensor is not accurate, the expiration induction output, the alcohol tester is judged according to the expiration pressure test result of the expiration test result of the real-time of the expiration date of the real-time of the alcohol tester 364932, the alcohol tester begins to the expiration test, the alcohol tester begins to the alcohol tester, the alcohol tester begins to the alcohol tester is accurate test, the.

Claims (2)

1. The utility model provides an electrochemistry alcohol tester based on high sensitive dynamic monitoring of pressure sensor breathes out breath sampling, includes MCU (1), power module (2), display (3), blow gun (4), electrochemistry alcohol sensor (5), alcohol sensor front end processing circuit (6), expired gas passageway (9), electrochemistry alcohol sensor (5) are passed through alcohol sensor front end processing circuit (6) with the first collection end ADC1 of MCU (1) is connected its characterized in that: the pressure acquisition device is characterized by further comprising a pressure sensor (7) and a pressure sensor induction amplifying circuit (8), wherein the pressure sensor (7) is connected with a second acquisition end ADC2 of the MCU (1) through the pressure sensor induction amplifying circuit (8).

2. The electrochemical alcohol tester for high-sensitivity dynamic monitoring of breath sampling based on pressure sensor of claim 1, wherein: the electrochemical alcohol sensor (5) and the pressure sensor (7) are separated by a perforated baffle (10) in the exhaled gas channel (9), and the distance from the perforated baffle (10) to the mouthpiece (4) is 1-2 cm.