Optimization method for realizing low-cost processor of exhalation type alcohol content detector

Abstract

The invention discloses an optimization method for calculating a detection value of an exhalation type alcohol detector by using a low-cost processor. By using the method, the hardware cost of the exhalation type alcohol detector can be reduced, and meanwhile, the requirement of detection precision is met.

Description

Technical Field

[0001] The present invention relates to the field of gas alcohol concentration detection, and particularly to an optimization method for realizing a low-cost processor of an exhaled alcohol content detector. Background Art

[0002] An exhaled gas alcohol content detector is an instrument used to detect whether a person has ingested alcohol and the degree of alcohol ingestion. Its usage scenarios are usually the pre-job, in-job, and post-job safety screenings of special operation personnel, such as drivers of cars, trains, airplanes, etc., and the safety inspections of workers in the petroleum, coal, or construction industries.

[0003] Currently, there are a wide variety of alcohol detectors sold in the market. In some professional detection scenarios, electrochemical alcohol gas sensors are used because of their high detection reliability and sensitivity.

[0004] However, in the current highly competitive market, to make the product competitive, it is necessary to reduce the product cost, but at the same time, the technical indicators of the product cannot be reduced. This invention patent provides an optimization method for a low-cost processor, that is, a low-cost processor can be used while meeting the current technical indicators. Summary of the Invention

[0005] The purpose of the present invention is to provide a brand-new method through in-depth research on the characteristics of electrochemical alcohol sensors and a large number of engineering practices, which can well solve the problem of still meeting the accuracy of detection results in the case of slow processing by a low-cost processor.

[0006] Compared with the prior art, the beneficial effects of the present invention are:

[0007] 1. Because a low-cost processor is used, the hardware cost of the instrument is low;

[0008] 2. Frequent and complex operations of the processor are not required, so the hardware power consumption is low, and the standby time of the handheld device can be increased. Brief Description of the Drawings

[0009] Figure 1 It is the circuit structure based on the algorithm of the present invention;

[0010] Figure 2 It is the output voltage amplitude and time characteristic diagram of the electrochemical alcohol sensor of the present invention. Detailed Embodiments

[0011] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. According to Figure 1 the hardware structure, the software algorithm running steps are as follows:

[0012] (1) A low-cost processor reads the sampled values of the sensor with a sampling period of Δt (since it is a low-cost processor, the sampling speed cannot be very high, so in engineering practice, the time interval of Δt is generally 25 ms). After sampling, the sampled values are stored and recorded.

[0013] (2) Continue to read and store the sampled values until the read value is less than a threshold value (according to engineering experience, this value is 5 mV when the output of the alcohol sensor decays).

[0014] (3) After the data sampling is completed, the sampling results are as Figure 2 , and the least squares function fitting is performed on the sampled values. According to engineering experience, the output function formula of the electrochemical alcohol sensor is as follows:

[0015]

[0016] (4) Use the least squares function fitting to calculate the values of I0 and τ.

[0017] (5) After the fitting is completed, an integral operation is performed on the fitting function. According to mathematical derivation, the integral value of I(t) is:

[0018]

[0019] Therefore, the integral value S is obtained only by the product of two coefficients.

[0020] (6) Multiply the integral value by the weighting coefficient K (determined according to the manual parameters of the alcohol sensor manufacturer), that is, the alcohol gas concentration value = K·S, so as to obtain the alcohol content detection value.

Claims

1. An optimization method for a low-cost processor of a breath alcohol tester, characterized in that, Including the following steps: (1) The processor reads the sampling values of the sensor with a sampling period of Δt, and stores and records the sampling values after sampling; (2) Continue to read and store the sampling values until the read value is less than a threshold; (3) After the data sampling is completed, perform a least squares function fitting on the sampling values. According to engineering experience, the output function of the electrochemical alcohol sensor is as follows: (4) Use the least squares function fitting to calculate the values of I0 and τ; After the fitting is completed, an integration operation is performed on the fitting function. According to mathematical derivation, the integral value of I(t) is: Therefore, the integral value S is obtained only by the product of two coefficients; (6) Multiply the integral value by the weighting coefficient K, that is, alcohol gas concentration value = K·S, so as to obtain the detection value of the alcohol gas content.

Images