Fire door photoelectric sensing switch circuit

Abstract

The utility model discloses a fireproof door photoelectricity response switch circuit, including power, infrared emission circuit, infrared receiving circuit, signal conditioning circuit and MCU, the power is used to give infrared emission circuit, infrared receiving circuit, signal conditioning circuit and MCU power supply, the PWM output end of MCU is electrically connected with the input of infrared emission circuit, infrared emission circuit output light signal, infrared receiving circuit receives corresponding light signal and converts it into electric signal, through the PWM output of MCU certain frequency square wave to promote infrared emission tube emission to take the square wave frequency of PWM output as the carrier wave infrared light wave, and infrared light wave irradiates on the fireproof door, formed the diffuse reflection infrared light wave, can judge the distance of distance reflecting surface according to the received light signal intensity. The fireproof door photoelectricity response switch circuit provided by the utility model has the effect that the opening and closing of the fireproof door are efficiently judged.

Description

Technical Field

[0001] This utility model relates to the field of fire door monitoring systems, and in particular to a photoelectric sensor switch circuit for fire doors. Background Technology

[0002] Fire doors are crucial components of fire alarm and linkage control systems, effectively isolating fires and toxic fumes. They are of great significance in ensuring personnel safety and minimizing property damage. The photoelectric sensor switch circuit for fire doors is a device that monitors the open / closed status of fire doors continuously over long periods. Therefore, reliable and effective long-term monitoring and ease of installation are particularly important for fire door photoelectric sensor switch circuits.

[0003] Existing fire door monitoring systems include mechanical, electromagnetic, and photoelectric types. Mechanical fire door monitoring systems primarily rely on a mechanical switch as the main monitoring component. Over time, metal fatigue and oxidation of the internal metal parts can cause poor contact in the springs, leading to monitoring failure. Electromagnetic fire door monitoring systems mainly consist of a permanent magnet and a magnetic induction switch. The permanent magnet in these systems may weaken or disappear, causing monitoring failure. Existing photoelectric fire door monitoring systems primarily rely on infrared emitters and receivers shining through each other, with an obstruction between them to monitor the fire door's status. Alternatively, one emitter and receiver can be mounted on the door and the other on the door frame, creating a through-beam system for monitoring. The biggest drawback of this method is its high installation requirements and cost. This paper proposes a monitoring circuit that utilizes the diffuse reflection of infrared light to monitor fire doors. Utility Model Content

[0004] To address the aforementioned problems, a photoelectric sensor switch circuit for fire doors is provided, aiming to solve the issues existing in the prior art.

[0005] The specific technical solution is as follows:

[0006] A photoelectric sensor switch circuit for a fire door includes a power supply, an infrared emitting circuit, an infrared receiving circuit, a signal conditioning circuit, and an MCU. The power supply provides power to the infrared emitting circuit, the infrared receiving circuit, the signal conditioning circuit, and the MCU. The PWM output terminal of the MCU is electrically connected to the input terminal of the infrared emitting circuit. The infrared emitting circuit outputs an optical signal, and the infrared receiving circuit receives the corresponding optical signal and converts it into an electrical signal. The output terminal of the infrared receiving circuit is electrically connected to the input terminal of the signal conditioning circuit, and the output terminal of the signal conditioning circuit is electrically connected to the ADC input terminal of the MCU.

[0007] The aforementioned fire door photoelectric sensor switch circuit also has the following feature: the power supply is used to convert the externally input voltage into the 3.3V required by this solution.

[0008] The aforementioned fire door photoelectric sensor switch circuit also has the following features: the infrared emitting circuit includes a resistor R26, a diode LED1, a transistor Q1, a resistor R23, and a resistor R24. The 3.3V voltage output by the power supply is connected to the anode of the diode LED1 after passing through the resistor R26. The cathode of the diode LED1 is connected to the collector of the transistor Q1. The base of the transistor Q1 is connected to its emitter through the resistor R24. The emitter of the transistor Q1 is grounded. The base of the transistor Q1 is connected to the PWM signal input terminal of the MCU through the resistor R23.

[0009] The aforementioned fire door photoelectric sensor switch circuit also has the following features: the infrared receiving circuit includes a capacitor C1, a resistor R1, and a diode LED7; the 3.3V voltage output from the power supply is electrically connected to the anode of the diode LED7 after passing through the capacitor C1; the 3.3V voltage output from the power supply is electrically connected to the cathode of the diode LED7 after passing through the resistor R1; the anode of the diode LED7 is grounded; and the cathode of the diode LED7 is electrically connected to the input terminal of the signal conditioning circuit as the output terminal.

[0010] The aforementioned fire door photoelectric sensor switch circuit also has the following features: the signal conditioning circuit includes a high-pass filter circuit and a conditioning amplifier circuit; the input terminal of the high-pass filter circuit is electrically connected to the cathode of the diode LED7; the output terminal of the high-pass filter circuit is electrically connected to the input terminal of the conditioning amplifier circuit; and the output terminal of the conditioning amplifier circuit is electrically connected to the ADC input terminal of the MCU.

[0011] The aforementioned fire door photoelectric sensor switch circuit also has the following features: the high-pass filter circuit includes a capacitor C3 and a resistor R4; one end of the capacitor C3 is connected to the cathode of the diode LED7 as an input terminal; the other end of the capacitor C3 is grounded through the resistor R4; and the common terminal of the capacitor C3 and the resistor R7 is connected to the conditioning amplifier circuit as an output terminal.

[0012] The aforementioned fire door photoelectric sensor switch circuit also has the following characteristics: the conditioning amplifier circuit includes resistor R3, resistor R7, capacitor C5, operational amplifier U7, resistor R9, capacitor C7, and resistor R32. The 3.3V voltage output by the power supply passes through resistor R3 and is electrically connected to the positive input terminal of operational amplifier U7. The positive input terminal of operational amplifier U7 also passes through resistor R4, capacitor C5, and resistor R7 in sequence and is electrically connected to its negative input terminal. The negative input terminal of operational amplifier U7 is also electrically connected to its output terminal through resistor R9. The output terminal of operational amplifier U7 passes through capacitor C7 and resistor R32 in sequence and is grounded. The common terminal of capacitor C7 and resistor R32 serves as the conditioning signal output terminal and is electrically connected to the ADC input terminal of the MCU.

[0013] In summary, the beneficial effects of this scheme are:

[0014] In the photoelectric sensor switch circuit for fire doors provided by this utility model, a square wave of a certain frequency is output by the PWM of the MCU to drive the infrared emitting tube to emit infrared light waves with the frequency of the square wave output by the PWM as the carrier. The infrared light waves illuminate the fire door, forming diffusely reflected infrared light waves. The distance to the reflecting surface can be determined based on the light signal. The photoelectric sensor switch circuit for fire doors provided by this utility model has the effect of efficiently determining whether the fire door is open or closed. Attached Figure Description

[0015] Figure 1 This is a structural block diagram of the photoelectric sensor switch circuit for fire doors according to this utility model;

[0016] Figure 2 This is a structural diagram of the infrared emitting circuit of the photoelectric sensor switch circuit for fire doors of this utility model.

[0017] Figure 3 This is a structural diagram of the infrared receiving circuit and signal conditioning circuit of the photoelectric sensor switch circuit for fire doors of this utility model. Detailed Implementation

[0018] The technical solution of this utility model will be clearly and completely described below with reference to its embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0020] The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the present invention.

[0021] Figure 1 This is a structural block diagram of the photoelectric sensor switch circuit for fire doors according to this utility model. Figure 2 This is a structural diagram of the infrared emitting circuit of the photoelectric sensor switch circuit for fire doors according to this utility model. Figure 3 This is a structural diagram of the infrared receiving circuit and signal conditioning circuit of the photoelectric sensor switch circuit for fire doors of this utility model, as shown below. Figures 1-3 As shown, the fire door photoelectric sensor switch circuit provided in this embodiment includes a power supply, an infrared emitting circuit, an infrared receiving circuit, a signal conditioning circuit, and an MCU. The power supply provides power to the infrared emitting circuit, the infrared receiving circuit, the signal conditioning circuit, and the MCU. The PWM output terminal of the MCU is electrically connected to the input terminal of the infrared emitting circuit. The infrared emitting circuit outputs a light signal, and the infrared receiving circuit receives the corresponding light signal and converts it into an electrical signal. The output terminal of the infrared receiving circuit is electrically connected to the input terminal of the signal conditioning circuit, and the output terminal of the signal conditioning circuit is electrically connected to the ADC input terminal of the MCU.

[0022] In the above embodiment, the power supply is used to convert the externally input voltage to the 3.3V required by this solution.

[0023] In the above embodiment, the infrared emitting circuit includes resistor R26, diode LED1, transistor Q1, resistor R23, and resistor R24. The 3.3V voltage output from the power supply is connected to the anode of diode LED1 after passing through resistor R26. The cathode of diode LED1 is connected to the collector of transistor Q1. The base of transistor Q1 is connected to its emitter through resistor R24. The emitter of transistor Q1 is grounded. The base of transistor Q1 is connected to the PWM signal input terminal of the MCU through resistor R23.

[0024] In the above embodiment, the infrared receiving circuit includes a capacitor C1, a resistor R1, and a diode LED7. The 3.3V voltage output from the power supply is electrically connected to the anode of the diode LED7 after passing through the capacitor C1. The 3.3V voltage output from the power supply is electrically connected to the cathode of the diode LED7 after passing through the resistor R1. The anode of the diode LED7 is grounded, and the cathode of the diode LED7 is electrically connected to the input terminal of the signal conditioning circuit as the output terminal.

[0025] In the above embodiments, the signal conditioning circuit includes a high-pass filter circuit and a conditioning amplifier circuit. The input terminal of the high-pass filter circuit is electrically connected to the cathode of the diode LED7, the output terminal of the high-pass filter circuit is electrically connected to the input terminal of the conditioning amplifier circuit, and the output terminal of the conditioning amplifier circuit is electrically connected to the ADC input terminal of the MCU.

[0026] In the above embodiment, the high-pass filter circuit includes a capacitor C3 and a resistor R4. One end of the capacitor C3 is connected to the cathode of the diode LED7 as an input terminal, and the other end of the capacitor C3 is grounded through the resistor R4. The common terminal of the capacitor C3 and the resistor R7 is connected to the conditioning amplifier circuit as an output terminal.

[0027] In the above embodiment, the conditioning amplifier circuit includes resistor R3, resistor R7, capacitor C5, operational amplifier U7, resistor R9, capacitor C7, and resistor R32. The 3.3V voltage output from the power supply is electrically connected to the positive input terminal of operational amplifier U7 after passing through resistor R3. The positive input terminal of operational amplifier U7 is also electrically connected to its negative input terminal after passing through resistor R4, capacitor C5, and resistor R7 in sequence. The negative input terminal of operational amplifier U7 is also electrically connected to its output terminal through resistor R9. The output terminal of operational amplifier U7 is grounded after passing through capacitor C7 and resistor R32 in sequence. The common terminal of capacitor C7 and resistor R32 serves as the conditioning signal output terminal and is electrically connected to the ADC input terminal of the MCU.

[0028] It should be noted that resistors R3 and R4 work together to adjust the voltage at the positive input terminal of op-amp U7 to 1.65V.

[0029] It should be noted that the MCU's PWM output produces a square wave of a certain frequency to drive the infrared emitting circuit to emit infrared light waves with the PWM output square wave frequency as the carrier. These infrared light waves illuminate the fire door, forming diffusely reflected infrared light waves. The infrared receiving diode on the device then converts the received diffusely reflected infrared light waves into a weak electrical signal. Through a conditioning and amplification circuit, this weak electrical signal is conditioned into a pulsating electrical signal of a certain amplitude. The amplitude of this pulsating electrical signal is proportional to the intensity of the received diffusely reflected light wave. The intensity of the diffusely reflected light wave is related to the distance and angle between the infrared emitting diode and the reflecting surface, as well as the roughness of the reflecting surface. The distance and angle between the external receiving diode and the reflective surface (fire door) are related. With the same surface roughness, if both the infrared emitting and receiving diodes are perpendicular to the reflective surface, the reflected infrared light is strongest at the same distance. Similarly, if the angles between the infrared emitting and receiving diodes and the reflective surface remain constant, the smaller the distance between the diodes and the reflective surface, the stronger the reflected infrared light. This device can determine the distance between the reflective surface and the device by reading the maximum amplitude of the conditioned pulsed electrical signal. If the distance exceeds a certain threshold, the reflected infrared light becomes very weak and cannot drive the infrared receiving diode. Therefore, by reading the maximum amplitude of the pulsed electrical signal, the distance between the device and the reflective surface can be determined. Based on these principles, this device can reliably determine the open and closed status of the fire door.

[0030] Working principle: The infrared emitting unit uses an NPN transistor Q1 as a switch to control the infrared emitting diode's emission and shutdown. The NPN transistor Q1 is controlled by a PWM square wave signal from the MCU. When the PWM square wave outputs a high level, the NPN transistor Q1 is on, and the infrared emitting diode emits infrared waves. When the PWM square wave outputs a low level, the NPN transistor Q1 is off, and the infrared emitting diode stops emitting infrared waves. This creates a modulated wave at the PWM frequency that emits infrared waves. The infrared receiving diode LED7 receives the reflected infrared waves. Upon receiving the infrared waveform, the infrared receiving diode LED7 adjusts its photoelectric sensitivity according to the strength of the received infrared waveform. The current will increase or decrease accordingly, thus converting the received infrared light wave signal into an electrical signal. Since there are certain infrared light waves in nature or indoor environments (sunlight and lamplight contain infrared light waves), but the intensity of these light waves does not change much, so the photocurrent of the infrared receiving diode LED7 is a fixed value. In this device, the infrared emission is an infrared light wave emitted by PWM as the carrier. Thus, a high-pass filter circuit can filter out the electrical signal with a fixed intensity, retaining the electrical signal converted from the PWM frequency carrier light wave. Then, the electrical signal converted from the weak reflected light signal is amplified by the subsequent two-stage signal amplification circuit and supplied to the MCU for detection.

[0031] The above are merely preferred embodiments of the present utility model and are not intended to limit the implementation methods and protection scope of the present utility model. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the content of the present utility model specification should be included within the protection scope of the present utility model.

Claims

1. A photoelectric sensing switch circuit for a fire door, characterized by: The system includes a power supply, an infrared emitting circuit, an infrared receiving circuit, a signal conditioning circuit, and an MCU. The power supply provides power to the infrared emitting circuit, the infrared receiving circuit, the signal conditioning circuit, and the MCU. The PWM output terminal of the MCU is electrically connected to the input terminal of the infrared emitting circuit. The infrared emitting circuit outputs an optical signal. The infrared receiving circuit receives the corresponding optical signal and converts it into an electrical signal. The output terminal of the infrared receiving circuit is electrically connected to the input terminal of the signal conditioning circuit. The output terminal of the signal conditioning circuit is electrically connected to the ADC input terminal of the MCU.

2. A photoelectric sensing switch circuit for a fire door according to claim 1 wherein: The power supply is used to convert the externally input voltage to the 3.3V required by this solution.

3. A photoelectric sensing switch circuit for a fire door according to claim 2, wherein: The infrared emitting circuit includes resistor R26, diode LED1, transistor Q1, resistor R23, and resistor R24. The 3.3V voltage output from the power supply is connected to the anode of diode LED1 after passing through resistor R26. The cathode of diode LED1 is connected to the collector of transistor Q1. The base of transistor Q1 is connected to its emitter through resistor R24. The emitter of transistor Q1 is grounded. The base of transistor Q1 is connected to the PWM signal input terminal of the MCU through resistor R23.

4. A photoelectric sensing switch circuit for a fire door according to claim 3 wherein: The infrared receiving circuit includes a capacitor C1, a resistor R1, and a diode LED7. The 3.3V voltage output from the power supply is connected to the anode of the diode LED7 through the capacitor C1, and the 3.3V voltage output from the power supply is connected to the cathode of the diode LED7 through the resistor R1. The anode of the diode LED7 is grounded, and the cathode of the diode LED7 is connected to the input terminal of the signal conditioning circuit as the output terminal.

5. A photoelectric sensing switch circuit for a fire door according to claim 4 wherein: The signal conditioning circuit includes a high-pass filter circuit and a conditioning amplifier circuit. The input terminal of the high-pass filter circuit is electrically connected to the cathode of the diode LED7, the output terminal of the high-pass filter circuit is electrically connected to the input terminal of the conditioning amplifier circuit, and the output terminal of the conditioning amplifier circuit is electrically connected to the ADC input terminal of the MCU.

6. A photoelectric sensing switch circuit for a fire door according to claim 5 wherein: The high-pass filter circuit includes a capacitor C3 and a resistor R4. One end of the capacitor C3 is connected to the cathode of the diode LED7 as an input terminal, and the other end of the capacitor C3 is grounded through the resistor R4. The common terminal of the capacitor C3 and the resistor R7 is connected to the conditioning amplifier circuit as an output terminal.

7. A photoelectric sensing switch circuit for a fire door according to claim 6 wherein: The conditioning and amplification circuit includes resistors R3 and R7, capacitor C5, operational amplifier U7, resistors R9 and C7, and resistor R32. The 3.3V voltage output from the power supply passes through resistor R3 and is electrically connected to the positive input terminal of operational amplifier U7. The positive input terminal of operational amplifier U7 also passes through resistors R4, C5, and R7 in sequence and is electrically connected to its negative input terminal. The negative input terminal of operational amplifier U7 is also electrically connected to its output terminal through resistor R9. The output terminal of operational amplifier U7 passes through capacitor C7 and resistor R32 in sequence and is grounded. The common terminal of capacitor C7 and resistor R32 serves as the conditioning signal output terminal and is electrically connected to the ADC input terminal of the MCU.

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