Photoelectric smoke-sensing fire detection alarm capable of resisting ambient light interference

Abstract

The utility model provides a photoelectric smoke-sensing fire detection alarm capable of resisting ambient light interference. The photoelectric smoke-sensing fire detection alarm comprises a maze, and a transmitting tube, a receiving tube and a control circuit which are arranged in the maze, the control circuit comprises a microcontroller, a transmitting tube circuit, a receiving tube circuit and an alarm; the microcontroller controls opening and closing of the transmitting tube, acquires an AD value output by the receiving tube in real time, and controls alarming of the alarm. The transmitting tube is set to be opened and closed according to a certain detection period; the AD value output by the receiving tube is a first AD value in a time period in which the transmitting tube is closed and does not work in a detection period; the AD value output by the receiving tube is a second AD value in the starting working time period of the transmitting tube in one detection period; in a detection period, if the first AD value is detected to be higher than the first set value, giving an alarm when the maze is irradiated by strong light or is not closed firmly; and if the difference value between the second AD value and the first AD value is detected to be higher than a second set value, performing smoke alarm.

Description

Technical Field

[0001] The utility model relates to the technical field of smoke detection, in particular to a photoelectric smoke fire detection alarm which is resistant to ambient light interference. Background Art

[0002] Currently, there are two common types of smoke detectors used for smoke detection: ionization smoke detectors and photoelectric smoke detectors. Ionization smoke detectors are more sensitive to tiny smoke ions and offer higher smoke detection sensitivity than photoelectric smoke detectors. They are generally used in locations with high smoke detection requirements. However, because they use radioactive materials (such as americium-241) to generate ions, they are less accepted in places like homes and offices. Photoelectric smoke detectors are more sensitive to slightly larger smoke ions. Smoke particles scatter some light, and the thicker the smoke, the more light is scattered onto the photosensitive receiving element. When the light scattered onto the receiving element reaches a certain level, the device will sound an alarm.

[0003] Photoelectric smoke detectors offer advantages such as greater stability, low power consumption, long life, and ease of installation. However, they are susceptible to interference from external light. A common practice is to completely enclose both the transmitter and receiver tubes within a black maze, with black mesh tape surrounding the maze to prevent the entry of foreign objects and block external light. This approach minimizes interference from external light on the receiver tubes. However, if the maze or the black mesh tape is damaged or improperly installed, interference from external light can cause false smoke alarms. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, a photoelectric smoke fire detection alarm that is resistant to ambient light interference is provided.

[0005] The technical solution adopted in this utility model is:

[0006] The utility model provides a photoelectric smoke fire detection alarm resistant to ambient light interference, comprising: a maze, a transmitting tube and a receiving tube arranged in the maze, and a control circuit arranged in the maze;

[0007] The control circuit includes a microcontroller, a transmitting tube circuit, a receiving tube circuit and an alarm;

[0008] The microcontroller pre-stores a first set value and a second set value; the first set value is the output AD value of the receiving tube when the transmitting tube is turned off and not working before the photoelectric smoke fire detection alarm leaves the factory; the second set value is the difference between the output AD value of the receiving tube when the transmitting tube is turned on and working before the photoelectric smoke fire detection alarm leaves the factory and the output AD value of the receiving tube when the transmitting tube is not working;

[0009] The microcontroller is connected to the transmitting tube circuit to control the opening and closing of the transmitting tube;

[0010] The microcontroller is connected to the receiving tube circuit to obtain the AD value output by the receiving tube in real time;

[0011] The microcontroller is connected to the alarm to control the alarm;

[0012] The transmitting tube is configured to be turned on and off according to a certain detection cycle;

[0013] During a detection cycle in which the transmitting tube is turned off and not working, the AD value output by the receiving tube is a first AD value; during a detection cycle in which the transmitting tube is turned on and working, the AD value output by the receiving tube is a second AD value;

[0014] In a detection cycle, if the microcontroller detects that the first AD value is higher than the first set value, the alarm device will issue an alarm indicating that the maze is illuminated by strong light or is not securely closed;

[0015] If the microcontroller detects that the difference between the second AD value and the first AD value is higher than the second set value, the alarm triggers a smoke alarm.

[0016] Based on the above, the launch tube includes a first launch tube and a second launch tube;

[0017] The angle between the optical axis of the first transmitting tube and the optical axis of the receiving tube is an obtuse angle, and the first transmitting tube and the receiving tube constitute a forward light path; the angle between the optical axis of the second transmitting tube and the optical axis of the receiving tube is an acute angle, and the second transmitting tube and the receiving tube constitute a backward light path.

[0018] Based on the above, the transmitting tube circuit includes a light-emitting diode LED2, a light-emitting diode LED3, a transistor Q1, a transistor Q4, a resistor R26 and a capacitor C17;

[0019] The resistor R26 and the capacitor C17 are connected in series between the VCC voltage terminal and the ground terminal;

[0020] The base of the transistor Q1 is connected to the output pin MCU_LED1 of the microcontroller through the resistor R17; the base of the transistor Q1 is grounded through the resistor R22, and the emitter is grounded through the resistor R23; the collector of the transistor Q1 is connected to the series connection point of the resistor R26 and the capacitor C17 through the light-emitting diode LED2;

[0021] The base of the transistor Q4 is connected to the output pin MCU_LED2 of the microcontroller via a resistor R33;

[0022] The base of the transistor Q4 is grounded via a resistor R31, and the emitter is grounded via a resistor R28;

[0023] The collector of the transistor Q4 is connected to the series connection point of the resistor R26 and the capacitor C17 through the light emitting diode LED3.

[0024] Based on the above, the microcontroller adopts STM32L151C6T series or STM32L412CB series single chip microcomputer.

[0025] The present invention has substantial features and advancements over the prior art. Specifically:

[0026] The utility model presets two set values, and then issues an alarm when the maze is exposed to strong light or is not securely closed, and issues a smoke alarm based on whether the output value of the receiving tube exceeds the corresponding set value when the transmitting tube is turned on and off, thereby solving the problem of false smoke alarms caused by external light interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a principle block diagram of the utility model.

[0028] Figure 2 This is the schematic diagram of the transmitting tube circuit.

[0029] Figure 3 This is a structural diagram of the transmitting tube and receiving tube of the utility model. DETAILED DESCRIPTION

[0030] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other without conflict.

[0031] like Figure 1 As shown, the utility model provides: a maze 1, a transmitting tube and a receiving tube arranged in the maze, and a control circuit arranged in the maze 1;

[0032] The control circuit includes a microcontroller, a transmitting tube circuit, a receiving tube circuit and an alarm;

[0033] The microcontroller pre-stores a first set value and a second set value; the first set value is the output AD value of the receiving tube when the transmitting tube is turned off and not working before the photoelectric smoke fire detection alarm leaves the factory; the second set value is the difference between the output AD value of the receiving tube when the transmitting tube is turned on and working before the photoelectric smoke fire detection alarm leaves the factory and the output AD value of the receiving tube when the transmitting tube is not working;

[0034] The microcontroller is connected to the transmitting tube circuit to control the opening and closing of the transmitting tube;

[0035] The microcontroller is connected to the receiving tube circuit to obtain the AD value output by the receiving tube in real time;

[0036] The microcontroller is connected to the alarm to control the alarm;

[0037] The transmitting tube is configured to be turned on and off according to a certain detection cycle;

[0038] During a detection cycle in which the transmitting tube is turned off and not working, the AD value output by the receiving tube is a first AD value; during a detection cycle in which the transmitting tube is turned on and working, the AD value output by the receiving tube is a second AD value;

[0039] In a detection cycle, if the microcontroller detects that the first AD value is higher than the first set value, the alarm device will issue an alarm indicating that the maze is illuminated by strong light or is not securely closed;

[0040] If the microcontroller detects that the difference between the second AD value and the first AD value is higher than the second set value, the alarm triggers a smoke alarm.

[0041] Preferably, if Figure 2 As shown, the transmitting tube circuit includes a light-emitting diode LED2, a light-emitting diode LED3, a transistor Q1, a transistor Q4, a resistor R26 and a capacitor C17;

[0042] The resistor R26 and the capacitor C17 are connected in series between the VCC voltage terminal and the ground terminal;

[0043] The base of the transistor Q1 is connected to the output pin MCU_LED1 of the microcontroller through the resistor R17; the base of the transistor Q1 is grounded through the resistor R22, and the emitter is grounded through the resistor R23; the collector of the transistor Q1 is connected to the series connection point of the resistor R26 and the capacitor C17 through the light-emitting diode LED2;

[0044] The base of the transistor Q4 is connected to the output pin MCU_LED2 of the microcontroller via a resistor R33;

[0045] The base of the transistor Q4 is grounded via a resistor R31, and the emitter is grounded via a resistor R28;

[0046] The collector of the transistor Q4 is connected to the series connection point of the resistor R26 and the capacitor C17 through the light emitting diode LED3.

[0047] The microcontroller adopts STM32L151C6T series or STM32L412CB series single chip microcomputer.

[0048] In some exemplary embodiments, Figure 3 As shown, the transmitting tube includes a first transmitting tube 2 and a second transmitting tube 3; the angle between the optical axis of the first transmitting tube 2 and the optical axis of the receiving tube 4 is an obtuse angle, and the first transmitting tube 2 and the receiving tube 4 constitute a forward light path; the angle between the optical axis of the second transmitting tube 3 and the optical axis of the receiving tube 4 is an acute angle, and the second transmitting tube 3 and the receiving tube 4 constitute a backward light path.

[0049] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A photoelectric smoke fire detection alarm that is resistant to ambient light interference, characterized in that: include: A maze, a transmitting tube and a receiving tube arranged in the maze, and a control circuit arranged in the maze; The control circuit includes a microcontroller, a transmitting tube circuit, a receiving tube circuit and an alarm; The microcontroller pre-stores a first set value and a second set value; the first set value is the output AD value of the receiving tube when the transmitting tube is turned off and not working before the photoelectric smoke fire detection alarm leaves the factory; the second set value is the difference between the output AD value of the receiving tube when the transmitting tube is turned on and working before the photoelectric smoke fire detection alarm leaves the factory and the output AD value of the receiving tube when the transmitting tube is not working; The microcontroller is connected to the transmitting tube circuit to control the opening and closing of the transmitting tube; The microcontroller is connected to the receiving tube circuit to obtain the AD value output by the receiving tube in real time; The microcontroller is connected to the alarm to control the alarm; The transmitting tube is configured to be turned on and off according to a certain detection cycle; During a detection cycle in which the transmitting tube is turned off and not working, the AD value output by the receiving tube is a first AD value; during a detection cycle in which the transmitting tube is turned on and working, the AD value output by the receiving tube is a second AD value; In a detection cycle, if the microcontroller detects that the first AD value is higher than the first set value, the alarm device will issue an alarm indicating that the maze is illuminated by strong light or is not securely closed; If the microcontroller detects that the difference between the second AD value and the first AD value is higher than the second set value, the alarm triggers a smoke alarm.

2. The photoelectric smoke fire detection alarm resistant to ambient light interference according to claim 1 is characterized in that: The launch tube includes a first launch tube and a second launch tube; The angle between the optical axis of the first transmitting tube and the optical axis of the receiving tube is an obtuse angle, and the first transmitting tube and the receiving tube constitute a forward light path; the angle between the optical axis of the second transmitting tube and the optical axis of the receiving tube is an acute angle, and the second transmitting tube and the receiving tube constitute a backward light path.

3. The photoelectric smoke fire detection alarm resistant to ambient light interference according to claim 2, characterized in that: The transmitting tube circuit includes a light emitting diode LED2, a light emitting diode LED3, a transistor Q1, a transistor Q4, a resistor R26 and a capacitor C17; The resistor R26 and the capacitor C17 are connected in series between the VCC voltage terminal and the ground terminal; The base of the transistor Q1 is connected to the output pin MCU_LED1 of the microcontroller through the resistor R17; the base of the transistor Q1 is grounded through the resistor R22, and the emitter is grounded through the resistor R23; the collector of the transistor Q1 is connected to the series connection point of the resistor R26 and the capacitor C17 through the light-emitting diode LED2; The base of the transistor Q4 is connected to the output pin MCU_LED2 of the microcontroller via a resistor R33; The base of the transistor Q4 is grounded via a resistor R31, and the emitter is grounded via a resistor R28; The collector of the transistor Q4 is connected to the series connection point of the resistor R26 and the capacitor C17 through the light emitting diode LED3.

4. The photoelectric smoke fire detection alarm capable of resisting ambient light interference according to any one of claims 1 to 3, characterized in that: The microcontroller adopts STM32L151C6T series or STM32L412CB series single chip microcomputer.

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