Water mist resistance algorithm based on independent photoelectric smoke sensing fire detection alarm

Abstract

The invention discloses a water mist resistant algorithm based on an independent photoelectric smoke sensing fire detection alarm, and relates to the technical field of fire detection, the algorithm comprises the following steps: a red and blue light double light source technology is adopted, the wavelength of infrared light is 940nm, the wavelength of blue light is 470nm, and the infrared light and the blue light are respectively transmitted through an infrared transmitting tube and a blue light transmitting tube. By adopting a red and blue light double-light-source technology, utilizing the characteristic that the wavelength of blue light is long and the scattering intensity of particles with small diameters is high and the detection capability of infrared light on particles with medium diameters, non-fire factors such as water mist and dust can be effectively distinguished, the false alarm rate caused by the water mist is remarkably reduced, and the fire hazard detection accuracy is improved. The alarm can more accurately judge the fire situation in a humid environment, false alarm is reduced, after water mist interference is judged, red and blue light continues sampling, the single-chip microcomputer keeps a wakeup state for continuous monitoring, alarm delay caused by water vapor generated at the high temperature of a fire can be effectively prevented, and the reliability of the alarm is improved.

Description

Technical Field

[0001] The invention relates to the technical field of fire detection, and in particular to an algorithm based on an independent photoelectric smoke fire detection alarm to resist water mist. Background Art

[0002] An independent photoelectric smoke fire detection alarm is a device used to detect smoke generated in the early stages of a fire and send out an alarm signal. In recent years, with the improvement of people's safety awareness, independent photoelectric smoke fire detection alarms have increasingly become standard equipment in family living rooms and bedrooms. This type of alarm is usually installed in homes, offices, public places and other areas to provide timely fire warnings and protect people's lives and property. Independent photoelectric smoke fire detection alarms use optical principles to detect smoke. When smoke enters the detection chamber of the detector, it scatters light, which is captured by the receiver in the detector and converted into electrical signals. When the smoke concentration reaches the preset threshold, the alarm will trigger an audible and visual alarm to alert people of the fire.

[0003] However, most traditional smoke detectors use single infrared light detection technology, which has some limitations. In practical applications, factors such as water mist and dust in the environment will interfere with the detection results of the detector. Traditional smoke detectors cannot identify water mist. In a humid environment, water mist may be mistaken for fire smoke, thereby causing false alarms, resulting in a high false alarm rate and causing unnecessary troubles for people. Therefore, it is necessary to propose an algorithm based on the anti-water mist of an independent photoelectric smoke fire detection alarm to solve the problems in the existing technology. Summary of the invention

[0004] The purpose of the present invention is to make up for the shortcomings of the prior art and to provide an algorithm based on the independent photoelectric smoke fire detection alarm to resist water mist. It can adopt red and blue light dual light source technology and use the ratio of the receiving tube's response to the two wavelengths of incident light to judge non-fire factors such as water mist and dust, thereby reducing the false alarm rate caused by water mist and dust, and identifying fires more quickly and accurately.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: an algorithm based on the anti-water fog of an independent photoelectric smoke fire detection alarm, the algorithm comprising:

[0006] It uses red and blue light dual light source technology, where the infrared light wavelength is 940nm and the blue light wavelength is 470nm, which are emitted by infrared emitting tube and blue light emitting tube respectively;

[0007] The short wavelength of blue light has a strong scattering intensity on small diameter particles, which improves the response to open flames. At the same time, infrared light is used to detect medium diameter particles to ensure sensitive response to smoldering fires.

[0008] The receiving tube receives incident light of two wavelengths and calculates the ratio of the blue light emission value to the infrared light emission value.

[0009] Set the threshold. When the ratio of the blue light emission value to the infrared light emission value is greater than or equal to 1.5, it is judged that a fire has occurred and the detector will send out an audible and visual alarm. When the ratio of the blue light emission value to the infrared light emission value is less than 1.5, it is judged to be interference from non-fire factors such as water mist and dust.

[0010] After judging that it is water mist interference, the red and blue light continue to be sampled. At this time, the microcontroller does not enter the sleep state and continues to monitor the ratio. In order to prevent the water vapor generated by the high temperature of the fire from not being recognized, resulting in delayed alarm, there will be a subsequent ratio If it is greater than or equal to 1.5, it is also judged as a fire alarm.

[0011] Furthermore, the infrared emitting tube and the blue light emitting tube adopt the IRB339-1C (XN) device of Everlight, which packages the light sources of two wavelengths together.

[0012] Furthermore, the receiving tube adopts Everlight's PD333-3C / H0 / L811 (XN) device, which has good absorption capabilities for wavelengths of 470nm and 940nm.

[0013] Furthermore, when the algorithm is operating normally, the MCU wakes up once every 13 seconds, during which time it only performs infrared light detection, turns off the blue light transmitting tube, turns on the infrared light periodically, and collects data periodically through the receiving tube. If the collected AD value is greater than the preset alarm value, the blue light function is started, and the infrared light and blue light are collected and the ratio is calculated in turn.

[0014] Furthermore, the receiving tube receives incident light of two wavelengths and calculates the ratio of the blue light emission value to the infrared light emission value. The following steps are involved:

[0015] After the infrared emitting tube emits 940nm infrared light and the blue light emitting tube emits 470nm blue light, the light interacts with particles and objects in the detection area. After the light is scattered by particles and objects, part of the energy of the scattered light is received by the receiving tube;

[0016] The receiving tube converts the energy of the received blue light and infrared light into corresponding electrical signals;

[0017] The circuit system processes and quantifies these electrical signals to obtain the measured value B of the blue light emission value and the measured value I of the infrared light emission value, and the ratio The calculation formula is expressed as:

[0018] Furthermore, in order to reduce the influence of errors and interference, it is necessary to measure the measured value B of the blue light emission value and the measured value I of the infrared light emission value multiple times, and take the average value as the final blue light emission value B and infrared light emission value I. The calculation process is as follows:

[0019] It is defined that n measurements are performed, and the blue light emission values ​​obtained in each measurement are B1, B2, ..., B n , the infrared light emission values ​​are measured as I1, I2, ..., I n ;

[0020] The calculation formula for the average value B of the blue light emission value is: The calculation formula for the average value I of the infrared light emission value is: The ratio of blue light emission value to infrared light emission value is The calculation formula is:

[0021] Furthermore, a threshold is set, and when the ratio of the blue light emission value to the infrared light emission value is greater than or equal to 1.5, it is judged that a fire has occurred, and the detector sends out an audible and visual alarm; when the ratio of the blue light emission value to the infrared light emission value is less than 1.5, it is judged that it is a non-fire factor interference such as water mist or dust, including the following steps:

[0022] According to experimental data and actual application requirements, the threshold is set to 1.5;

[0023] Continuously calculate the ratio of blue light emission value to infrared light emission value

[0024] The calculated ratio Compared with the set threshold of 1.5, If a fire occurs, the detector will immediately send out an audible and visual alarm to remind people to take appropriate measures.

[0025] The calculated ratio Compared with the set threshold of 1.5, It was determined to be interference from non-fire factors such as water mist and dust.

[0026] Furthermore, in the above specific steps, the threshold determination formula is: Among them, f(IR, BLUE) represents the judgment result. A result of 1 indicates that a fire has occurred, and a result of 0 indicates that the fire is interfered by non-fire factors such as water mist and dust.

[0027] Furthermore, after judging that it is water mist interference, the red and blue light continue to be sampled. At this time, the microcontroller does not enter the sleep state and continues to monitor the ratio. There is a subsequent ratio If it is greater than or equal to 1.5, it is also judged as a fire alarm, including the following steps:

[0028] After judging that it is water mist interference, the red and blue light transmitting tube continues to work and continuously emits red and blue light, and the receiving tube continues to receive the incident light of red and blue light and converts it into electrical signals. The single-chip microcomputer does not enter the sleep state, but remains active and processes the electrical signals from the receiving tube in real time.

[0029] The microcontroller processes the received electrical signal and calculates the ratio at the current moment. Define t as a time series, Represents the ratio at time t

[0030] The calculated ratio Compare and record with previous monitoring results, repeat this process continuously, and monitor the ratio in real time The process of continuous monitoring is expressed as: Wherein, f(t) represents the judgment result at time t. When the result is 1, it means that it is judged as a fire alarm, and when the result is 0, it means that it is still judged as water mist interference and other non-fire factors interference.

[0031] The microcontroller will calculate at each time point t The value of is determined according to the above formula. As long as there is one time in the subsequent monitoring that satisfies It will trigger a fire alarm. Once it is determined to be a fire alarm, the microcontroller immediately controls the detector to send out sound and light alarm signals to remind people to take appropriate fire extinguishing and escape measures.

[0032] Compared with the existing technology, the anti-water mist algorithm based on the independent photoelectric smoke fire detection alarm has the following beneficial effects:

[0033] The present invention adopts red and blue light dual light source technology, utilizes the characteristics of blue light's short wavelength and high scattering intensity for particles with small diameters, and infrared light's detection ability for particles with medium diameters, and can effectively distinguish non-fire factors such as water mist and dust, significantly reducing the false alarm rate caused by water mist, so that the alarm can more accurately judge the fire situation in a humid environment and reduce the occurrence of false alarms. After judging that it is water mist interference, the red and blue lights continue to sample, and the single-chip computer remains in an awake state for continuous monitoring, which can effectively prevent the water vapor generated under the high temperature of the fire from causing alarm delays, thereby improving the reliability of the alarm.

[0034] Other advantages, objectives and features of the present invention will be set forth in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 It is a flow chart of an algorithm based on the anti-water mist of an independent photoelectric smoke fire detection alarm;

[0037] Figure 2 This is the test curve of n-heptane;

[0038] Figure 3 This is the test curve of beech wood;

[0039] Figure 4 It is the curve diagram of cotton strip test;

[0040] Figure 5 This is a polyurethane test curve;

[0041] Figure 6 This is the water mist experiment curve. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Embodiment 1

[0044] from Figure 2-Figure 6 It can be seen that the curves of red and blue light for fire particles: SH1, SH2, SH3, SH4 and water mist are obviously inconsistent. The dispersed light of water mist is almost unaffected by the BLUE / IR ratio, which is basically 1.0. Because the particle diameter of water mist is much larger than the wavelength of infrared light and blue light, this provides the detector with basic data for identifying fire particles and water mist. Based on this data, a set of algorithms that can identify water mist and fire particles are derived.

[0045] An algorithm based on the anti-water mist of an independent photoelectric smoke fire detection alarm includes: using red and blue light dual light source technology, wherein the infrared light wavelength is 940nm and the blue light wavelength is 470nm, which are emitted by an infrared emitting tube and a blue light emitting tube respectively. The infrared emitting tube and the blue light emitting tube use Everlight's IRB339-1C (XN) device, which encapsulates the two wavelengths of light sources together, and utilizes the characteristics of the short wavelength of blue light and the high scattering intensity of small diameter particles to improve the response to open flames, and at the same time utilizes infrared light to detect medium diameter particles to ensure sensitive response to smoldering fires.

[0046] The receiving tube receives incident light of two wavelengths and calculates the ratio of the blue light emission value to the infrared light emission value. The receiving tube adopts Everlight's PD333-3C / H0 / L811 (XN) device, which has good absorption capabilities for wavelengths of 470nm and 940nm.

[0047] The threshold is set to 1.5. If the ratio of the blue light emission value to the infrared light emission value is greater than or equal to 1.5, it is judged that a fire has occurred and the detector sends out an audible and visual alarm. If the ratio of the blue light emission value to the infrared light emission value is less than 1.5, it is judged to be interference from non-fire factors such as water mist and dust. After it is judged to be water mist interference, the red and blue light continue to be sampled. At this time, the MCU does not enter the sleep state and continues to monitor the ratio. In order to prevent the water vapor generated by the high temperature of the fire from not being recognized, resulting in delayed alarm, there will be a subsequent ratio If it is greater than or equal to 1.5, it is also judged as a fire alarm.

[0048] When the algorithm is operating normally, the MCU wakes up once every 13 seconds, during which time it only performs infrared light detection, turns off the blue light emitting tube, turns on the infrared light periodically, and collects data periodically through the receiving tube. When the collected AD value is greater than the preset alarm value, the blue light function is started, and infrared light and blue light are collected and ratio calculated in turn. The ratio of each blue light emission value to the infrared light emission value is calculated. If the ratio is greater than or equal to 1.5, it is determined that a fire has occurred, and the detector sends out an audible and visual alarm. If the ratio is less than 1.5, it is determined to be water mist interference. After it is determined to be water mist interference, red and blue light continue to be sampled, and the microcontroller does not enter sleep mode. When the BLUE / IR ratio is greater than or equal to 1.5, it is determined to be a fire alarm to prevent the water vapor generated under the high temperature of the fire from being unrecognized, resulting in alarm delays.

[0049] Embodiment 2

[0050] This embodiment is a further detailed description of an algorithm for resisting water mist based on an independent photoelectric smoke fire detection alarm based on the first embodiment.

[0051] The receiving tube is in the position of receiving blue light and infrared light, ensuring that the incident light of two wavelengths can accurately irradiate the receiving tube. After the infrared transmitting tube emits 940nm infrared light and the blue light transmitting tube emits 470nm blue light, the light interacts with particles and objects in the detection area. After the light is scattered by particles and objects, part of the energy of the scattered light is received by the receiving tube. The receiving tube converts the energy of the received blue light and infrared light into corresponding electrical signals. The circuit system processes and quantifies these electrical signals to obtain the measurement value B of the blue light emission value and the measurement value I of the infrared light emission value, and the ratio The calculation formula is expressed as:

[0052] In order to reduce the influence of errors and interference, it is necessary to measure the measured value B of the blue light emission value and the measured value I of the infrared light emission value for multiple times, and take the average value as the final blue light emission value B and infrared light emission value I. The calculation process is as follows: define n measurements, and the measured values ​​of the blue light emission value obtained in each measurement are B1, B2, ..., B n , the infrared light emission values ​​are measured as I1, I2, ..., I n , the calculation formula for the average value B of the blue light emission value is: The calculation formula for the average value I of the infrared light emission value is: The ratio of blue light emission value to infrared light emission value is The calculation formula is:

[0053] Then, according to the experimental data and actual application requirements, the threshold is set to 1.5, and the ratio of the blue light emission value to the infrared light emission value is continuously calculated. The calculated ratio Compared with the set threshold of 1.5, If a fire occurs, the detector will immediately send out an audible and visual alarm to remind people to take appropriate measures. Compared with the set threshold of 1.5, It is judged that the non-fire factors such as water mist and dust interfere with the fire. In this case, the detector will continue to monitor the ratio. To ensure that possible signs of fire are not missed, the threshold judgment formula is: Among them, f(IR, BLUE) represents the judgment result. A result of 1 indicates that a fire has occurred, and a result of 0 indicates that the fire is interfered by non-fire factors such as water mist and dust.

[0054] After judging that it is water mist interference, the red and blue light transmitting tube continues to work and continuously emits red and blue light. The receiving tube continues to receive the incident light of red and blue light and converts it into electrical signals. The single-chip microcomputer does not enter the sleep state, but remains active and processes the electrical signals from the receiving tube in real time. The single-chip microcomputer processes the received electrical signals and calculates the ratio at the current moment. Define t as a time series, Represents the ratio at time t The calculated ratio Compare and record with previous monitoring results, repeat this process continuously, and monitor the ratio in real time The process of continuous monitoring is expressed as: Wherein, f(t) represents the judgment result at time t. When the result is 1, it indicates that it is judged as a fire alarm, and when the result is 0, it indicates that it is still judged as water mist interference and other non-fire factors interference.

[0055] Since water vapor may be generated under high temperature of fire, this water vapor may interfere with the detection of sensors, resulting in misjudgment of water mist interference. It can timely detect signs of fire that may be covered by water vapor, ensuring that when a fire occurs, an alarm signal can be issued promptly and accurately to avoid alarm delays. The microcontroller will calculate at each time point t The value of is determined according to the above formula. As long as there is one time in the subsequent monitoring that satisfies It will trigger a fire alarm. Once it is determined to be a fire alarm, the microcontroller immediately controls the detector to send out sound and light alarm signals to remind people to take appropriate fire extinguishing and escape measures.

[0056] In summary, the algorithm adopts red and blue light dual light source technology, utilizing the short wavelength of blue light and its strong scattering intensity on small-diameter particles, as well as the detection ability of infrared light on medium-diameter particles. It can effectively distinguish non-fire factors such as water mist and dust, and significantly reduce the false alarm rate caused by water mist. After judging it as water mist interference, the red and blue lights continue to sample, and the single-chip microcomputer remains awake for continuous monitoring, which can effectively prevent the water vapor generated under the high temperature of the fire from causing alarm delays, thereby improving the reliability of the alarm.

[0057] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the same elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An algorithm based on the anti-water mist of an independent photoelectric smoke fire detection alarm, characterized in that: The algorithm includes: It uses red and blue light dual light source technology, where the infrared light wavelength is 940nm and the blue light wavelength is 470nm, which are emitted by infrared emitting tube and blue light emitting tube respectively; The short wavelength of blue light has a strong scattering intensity on small diameter particles, which improves the response to open flames. At the same time, infrared light is used to detect medium diameter particles to ensure sensitive response to smoldering fires. The receiving tube receives incident light of two wavelengths and calculates the ratio of the blue light emission value to the infrared light emission value. Set the threshold. When the ratio of the blue light emission value to the infrared light emission value is greater than or equal to 1.5, it is judged that a fire has occurred and the detector will send out an audible and visual alarm. When the ratio of the blue light emission value to the infrared light emission value is less than 1.5, it is judged to be interference from non-fire factors such as water mist and dust. After judging that it is water mist interference, the red and blue light continue to be sampled. At this time, the microcontroller does not enter the sleep state and continues to monitor the ratio. There is a subsequent ratio If it is greater than or equal to 1.5, it is also judged as a fire alarm.

2. The algorithm for resisting water mist based on an independent photoelectric smoke fire detection alarm according to claim 1 is characterized in that: The infrared emitting tube and the blue light emitting tube adopt the IRB339-1C (XN) device of Everlight, which packages the light sources of two wavelengths together.

3. The algorithm for resisting water mist based on an independent photoelectric smoke fire detection alarm according to claim 1 is characterized in that: The receiving tube adopts Everlight's PD333-3C / H0 / L811 (XN) device, which has good absorption capabilities for wavelengths of 470nm and 940nm.

4. The algorithm for resisting water mist based on an independent photoelectric smoke fire detection alarm according to claim 1 is characterized in that: When the algorithm is operating normally, the MCU wakes up once every 13 seconds, during which time it only performs infrared light detection, turns off the blue light transmitting tube, turns on the infrared light periodically, and collects data periodically through the receiving tube. When the collected AD value is greater than the preset alarm value, the blue light function is started, and the infrared light and blue light are collected and the ratio is calculated in turn.

5. The algorithm for resisting water mist based on an independent photoelectric smoke fire detection alarm according to claim 1 is characterized in that: The receiving tube receives incident light of two wavelengths and calculates the ratio of the blue light emission value to the infrared light emission value. The following steps are involved: After the infrared emitting tube emits 940nm infrared light and the blue light emitting tube emits 470nm blue light, the light interacts with particles and objects in the detection area. After the light is scattered by particles and objects, part of the energy of the scattered light is received by the receiving tube; The receiving tube converts the energy of the received blue light and infrared light into corresponding electrical signals; The circuit system processes and quantifies these electrical signals to obtain the measured value B of the blue light emission value and the measured value I of the infrared light emission value, and the ratio The calculation formula is expressed as:

6. The algorithm for resisting water mist based on an independent photoelectric smoke fire detection alarm according to claim 5 is characterized in that: In order to reduce the influence of errors and interference, it is necessary to measure the measured value B of the blue light emission value and the measured value I of the infrared light emission value multiple times, and take the average value as the final blue light emission value B and infrared light emission value I. The calculation process is as follows: It is defined that n measurements are performed, and the blue light emission values ​​obtained in each measurement are B1, B2, ..., B n , the infrared light emission values ​​are measured as I1, I2, ..., I n ; The calculation formula for the average value B of the blue light emission value is: The calculation formula for the average value I of the infrared light emission value is: The ratio of blue light emission value to infrared light emission value is The calculation formula is:

7. The algorithm for resisting water mist based on an independent photoelectric smoke fire detection alarm according to claim 1 is characterized in that: The threshold is set. When the ratio of the blue light emission value to the infrared light emission value is greater than or equal to 1.5, it is judged that a fire has occurred and the detector sends out an audible and visual alarm. When the ratio of the blue light emission value to the infrared light emission value is less than 1.5, it is judged that it is a non-fire factor interference such as water mist or dust. The following steps are included: According to experimental data and actual application requirements, the threshold is set to 1.5; Continuously calculate the ratio of blue light emission value to infrared light emission value The calculated ratio Compared with the set threshold of 1.5, If a fire occurs, the detector will immediately send out an audible and visual alarm to remind people to take appropriate measures. The calculated ratio Compared with the set threshold of 1.5, It was determined to be interference from non-fire factors such as water mist and dust.

8. The algorithm for resisting water mist based on an independent photoelectric smoke fire detection alarm according to claim 7 is characterized in that: In the above specific steps, the threshold determination formula is: Among them, f(IR, BLUE) represents the judgment result. A result of 1 indicates that a fire has occurred, and a result of 0 indicates that the fire is interfered by non-fire factors such as water mist and dust.

9. The algorithm for resisting water mist based on an independent photoelectric smoke fire detection alarm according to claim 1 is characterized in that: After judging that it is water mist interference, the red and blue light continue to be sampled. At this time, the microcontroller does not enter the sleep state and continues to monitor the ratio. There is a subsequent ratio If it is greater than or equal to 1.5, it is also judged as a fire alarm, including the following steps: After judging that it is water mist interference, the red and blue light transmitting tube continues to work and continuously emits red and blue light, and the receiving tube continues to receive the incident light of red and blue light and converts it into electrical signals. The single-chip microcomputer does not enter the sleep state, but remains active and processes the electrical signals from the receiving tube in real time. The microcontroller processes the received electrical signal and calculates the ratio at the current moment. Define t as a time series, Represents the ratio at time t The calculated ratio Compare and record with previous monitoring results, repeat this process continuously, and monitor the ratio in real time The process of continuous monitoring is expressed as: Wherein, f(t) represents the judgment result at time t. When the result is 1, it means that it is judged as a fire alarm, and when the result is 0, it means that it is still judged as water mist interference and other non-fire factors interference. The microcontroller will calculate at each time point t The value of is determined according to the above formula. As long as there is one time in the subsequent monitoring that satisfies It will trigger a fire alarm. Once it is judged as a fire alarm, the microcontroller immediately controls the detector to send out sound and light alarm signals to remind people to take appropriate fire extinguishing and escape measures.

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