A security camera motor limit position protection circuit

Abstract

The present application belongs to the field of security monitoring equipment, and relates to a security camera motor limit position protection circuit. The circuit includes a forward control circuit, based on the transistor Q3 controlling the first end of the motor to access the power supply, and driving the transistor Q6 to ground the second end of the motor; a reverse control circuit, based on the transistor Q4 controlling the second end of the motor to access the power supply, and driving the transistor Q5 to ground the first end of the motor; a rotation locking circuit, based on the transistor Q9 managing the output voltage of the control lock output interface, the control lock output interface connects the base of the transistor Q3 and the transistor Q4 through a reverse diode, the base of the transistor Q9 is connected before the motor grounding resistor R15, when the motor is normal, the base voltage of the transistor Q9 is low, when the motor is stuck, the base voltage of the transistor Q9 increases and turns on, so that the control lock output interface outputs a low level, and the motor power supply is cut off. The present application can prevent the motor from getting stuck and damaged, and improve the reliability and safety of the system.

Description

Technical Field

[0001] The present application belongs to the field of security monitoring equipment, and in particular to a security camera motor limit position protection circuit. Background Art

[0002] In the field of security monitoring equipment, security cameras usually need to rotate to cover a wider monitoring range. This rotation function is often achieved by a motor. However, when the camera rotates to the extreme position of the structural frame, if the control is not appropriate, the motor may be forced to rotate, causing damage or jamming of the motor. This will not only shorten the service life of the motor, but may also affect the stable operation of the entire security monitoring system.

[0003] The common solutions to this problem in the industry can be summarized as follows:

[0004] 1. Structural limit switch: By setting a physical limit switch on the rotating structure of the security camera, when the camera rotates to the limit position, the switch will be triggered to cut off the power supply of the motor, thereby preventing the motor from continuing to rotate. Although this method is simple and direct, it increases the complexity of the structure, and the switch is prone to wear and failure over a long period of use, affecting the reliability of the system.

[0005] 2. Software control limitation: The software limitation is implemented through the microcontroller unit (MCU) built into the camera, that is, the upper and lower limits of the rotation angle are set by programming. When the camera reaches the limit position, the MCU will stop sending rotation signals to the motor. However, this method relies on the stability and accuracy of the software. Once the software fails or responds untimely, it may also cause damage to the motor.

[0006] 3. A method that combines structural limitations and electronic monitoring: For example, some security cameras may have physical limitations set on the structure, and detect the position of the motor through Hall sensors or other position sensors. When the motor approaches the limit position, the sensor sends a signal to the MCU, which decides whether to stop the motor. The advantage of this solution is that it combines the safety of physical limitations and the flexibility of electronic monitoring. However, it still relies on the limitations of physical structure, and the addition of sensors increases the complexity and cost of the system. In addition, the sensor itself may fail, requiring additional maintenance and calibration.

[0007] It can be seen that in the prior art, the anti-jamming protection is mainly carried out by setting the forward and reverse rotation time periods of the motor and the overload protection facilities. However, this protection method has some shortcomings. For example, if the jamming situation occurs in the set forward and reverse rotation time period and the fault is not eliminated in time, there is a hidden danger of burning the motor. Summary of the invention

[0008] In order to solve the above technical problems, the present application provides a security camera motor limit position protection circuit to monitor the working current of the motor in real time and take protective measures immediately when an abnormality is detected to prevent the motor from getting stuck and damaged.

[0009] The security camera motor limit position protection circuit provided in this application mainly includes:

[0010] The forward control circuit includes a transistor Q3, the base of which is connected to the first output interface PA1 of the control chip MCU, and is used to connect the first end of the motor M1 to the high voltage when the first output interface PA1 outputs a high voltage, and drive the transistor Q6 located between the second end of the motor M1 and the ground end to conduct by means of the high voltage of the first end, so that the second end of the motor M1 is grounded after passing through the resistor R15;

[0011] The reverse control circuit includes a transistor Q4, the base of which is connected to the second output interface PA2 of the control chip MCU, and is used to connect the second end of the motor M1 to the high voltage when the second output interface PA2 outputs a high voltage, and drive the transistor Q5 located between the first end of the motor M1 and the ground end to conduct by means of the high voltage at the second end, so that the first end of the motor M1 is grounded after passing through the resistor R15;

[0012] The rotation locking circuit includes a transistor Q9, a voltage output end of which is grounded after passing through a resistor R7 and the transistor Q9, a control lock output interface LOCKED is provided between the resistor R7 and the transistor Q9, the control lock output interface LOCKED is connected to the base of the transistor Q3 of the forward control circuit, and the base of the transistor Q4 of the reverse control circuit, the base of the transistor Q9 is connected between the resistor R15 and the motor M1, when the motor M1 rotates normally, the base voltage of the transistor Q9 is insufficient to turn on the transistor Q9, when the motor M1 is stuck, the current flowing through the resistor R15 increases, and the base voltage of the transistor Q9 is increased to turn on the transistor Q9.

[0013] Preferably, the collector of the transistor Q3 of the forward control circuit is connected to the base of the transistor Q1 through the resistor R1, the emitter of the transistor Q1 is connected to the power supply, and the collector of the transistor Q1 is connected to the first end of the motor M1.

[0014] Preferably, the collector of the transistor Q4 of the reversing control circuit is connected to the base of the transistor Q2 via the resistor R2, the emitter of the transistor Q2 is connected to the power supply, and the collector of the transistor Q2 is connected to the second end of the motor M1.

[0015] Preferably, a resistor R12 and a resistor R13 are provided between the transistor Q9 and the non-grounded end of the resistor R15, a line between the resistor R12 and the resistor R13 is connected to a first end of the capacitor C1, and a second end of the capacitor C1 is grounded.

[0016] Preferably, the first end of the capacitor C1 is further connected to the non-grounded end of the resistor R15 via a diode D7.

[0017] Preferably, the control lock output interface LOCKED is also connected to the third output interface PA3 of the control chip MCU, and the control chip MCU is configured to send a signal that the motor M1 is stuck to the host computer when the third output interface PA3 is pulled low.

[0018] The present application can monitor the working status of the motor in real time and take protective measures immediately when an abnormality is detected, effectively preventing the motor from getting stuck and damaged, and improving the reliability and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a circuit structure diagram of a preferred embodiment of the security camera motor limit position protection circuit of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and cannot be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in combination with the drawings.

[0021] The present application provides a security camera motor limit position protection circuit, such as Figure 1 As shown, it mainly includes:

[0022] The forward control circuit includes a transistor Q3, the base of which is connected to the first output interface PA1 of the control chip MCU, and is used to connect the first end of the motor M1 to the high voltage when the first output interface PA1 outputs a high voltage, and drive the transistor Q6 located between the second end of the motor M1 and the ground end to conduct by means of the high voltage of the first end, so that the second end of the motor M1 is grounded after passing through the resistor R15;

[0023] The reverse control circuit includes a transistor Q4, the base of which is connected to the second output interface PA2 of the control chip MCU, and is used to connect the second end of the motor M1 to the high voltage when the second output interface PA2 outputs a high voltage, and drive the transistor Q5 located between the first end of the motor M1 and the ground end to conduct by means of the high voltage at the second end, so that the first end of the motor M1 is grounded after passing through the resistor R15;

[0024] The rotation locking circuit includes a transistor Q9, a voltage output end of which is grounded after passing through a resistor R7 and the transistor Q9, a control lock output interface LOCKED is provided between the resistor R7 and the transistor Q9, the control lock output interface LOCKED is connected to the base of the transistor Q3 of the forward control circuit, and the base of the transistor Q4 of the reverse control circuit, the base of the transistor Q9 is connected between the resistor R15 and the motor M1, when the motor M1 rotates normally, the base voltage of the transistor Q9 is insufficient to turn on the transistor Q9, when the motor M1 is stuck, the current flowing through the resistor R15 increases, and the base voltage of the transistor Q9 is increased to turn on the transistor Q9.

[0025] In the present application, when the first output interface PA1 of the control chip MCU outputs a high voltage, the 5V voltage can be connected to the first end of the motor, and the transistor Q6 is driven to ground the second end of the motor to complete the forward control of the motor. When the output interface PA2 of the control chip MCU outputs a high voltage, the 5V voltage can be connected to the second end of the motor, and the first end of the motor is grounded with the help of the transistor Q5 to complete the reverse control of the motor. When the motor is running normally, the current flowing through the resistor R15 is small, and the voltage drop on R15 is low, which is not enough to turn on the transistor Q9 of the rotation locking circuit. The control lock output interface LOCKED of the rotation locking circuit outputs a high level, which is connected to the forward control circuit through a reverse diode D3 and to the reverse control circuit through a reverse diode D4 to prevent the high level of the original forward control circuit or the reverse control circuit from being pulled down, so that the motor can work continuously and stably. When the motor is stuck abnormally, the current flowing through the resistor R15 increases, and the voltage drop on R15 increases, so that the base voltage of the transistor Q9 of the rotation locking circuit increases to turn on the transistor Q9, and the voltage of the rotation locking circuit is grounded after the resistor R7, that is, the voltage of the control lock output interface LOCKED is pulled down, thereby pulling down the high level of the original forward control circuit or the reverse control circuit, that is, the voltage acting on the base of the transistor Q3 or the base of the transistor Q4 decreases, and the power supply of the motor M1 is cut off, avoiding the situation where the motor is forced to rotate continuously.

[0026] In some optional embodiments, the collector of the transistor Q3 of the forward control circuit is connected to the base of the transistor Q1 through the resistor R1, the emitter of the transistor Q1 is connected to the power supply, and the collector of the transistor Q1 is connected to the first end of the motor M1.

[0027] refer to Figure 1 When the security camera is powered on for self-test or rotated by APP remote control, the first output interface PA1 of the control chip MCU outputs a high level, and the NPN transistor Q3 is turned on after passing through the resistor R3 and the diode D1, and the emitter of the transistor Q3 is grounded, thereby pulling down the base voltage of the PNP transistor Q1 through the resistor R1, so that the transistor Q1 is turned on, and the 5V voltage can be added to the 1 pin of the motor M1 through the transistor Q1, that is, the first end of the motor M1. The 5V voltage can also be further applied to the base of the NPN transistor Q6 through the resistor R6, that is, the transistor Q6 inputs a high level, so that the transistor Q6 is turned on, so that the second end of the motor M1 can be grounded through the resistor R15, that is, this embodiment makes the motor rotate forward through the conduction of the transistor Q1 and the transistor Q6.

[0028] In some optional embodiments, the collector of the transistor Q4 of the reversing control circuit is connected to the base of the transistor Q2 through the resistor R2, the emitter of the transistor Q2 is connected to the power supply, and the collector of the transistor Q2 is connected to the second end of the motor M1.

[0029] refer to Figure 1 When the security camera is powered on for self-test or rotated by APP remote control, the second output interface PA2 of the control chip MCU outputs a high level, which turns on the NPN transistor Q4 after passing through the resistor R4 and the diode D2, and the emitter of the transistor Q4 is grounded, thereby pulling down the base voltage of the PNP transistor Q2 through the resistor R2, so that the transistor Q2 is turned on, and the 5V voltage can be added to the 2nd foot of the motor M1 through the transistor Q2, that is, the second end of the motor M1. The 5V voltage can be further applied to the base of the NPN transistor Q5 through the resistor R5, that is, the transistor Q5 inputs a high level, so that the transistor Q5 is turned on, so that the first end of the motor M1 can be grounded through the resistor R15, that is, this embodiment reverses the motor by turning on the transistor Q2 and the transistor Q5.

[0030] In some optional implementations, resistors R12 and R13 are provided between the transistor Q9 and the non-grounded end of the resistor R15, a line between the resistors R12 and R13 is connected to a first end of the capacitor C1, and a second end of the capacitor C1 is grounded.

[0031] In this embodiment, since the current flowing through the resistor R15 is unstable when the motor is abnormally stuck, that is, the control voltage of the base of the transistor Q9 is unstable, a capacitor C1 is added here to charge the capacitor C1 through the resistor. When the motor is stuck for a longer time and the accumulated charging voltage on the capacitor C1 reaches 0.7V, the NPN transistor Q9 is turned on, and then as mentioned above, the high level sent by the chip to the motor control end is pulled down with the help of the control lock output interface LOCKED, so that the power supply transistor of the entire motor cannot be turned on, thereby turning off the power supply to the motor.

[0032] In some optional implementations, the first end of the capacitor C1 is further connected to the non-grounded end of the resistor R15 through a diode D7.

[0033] In this embodiment, the voltage of resistor R15 increases, and capacitor C1 is slowly charged through resistor R12. When the entire motor control circuit is turned off, the charge stored in capacitor C1 is quickly discharged to resistor R15 through diode D7, making new preparations for the next cumulative charging.

[0034] In some optional implementations, the control lock output interface LOCKED is also connected to the third output interface PA3 of the control chip MCU, and the control chip MCU is configured to send a signal that the motor M1 is stuck to the host computer when the third output interface PA3 is pulled low.

[0035] In this embodiment, when the control lock output interface LOCKED connected to the collector of the transistor Q9 outputs a low level, it also pulls down the 5-pin PA3 of the control chip MCU. That is, after the third output interface PA3 is pulled low, the control chip MCU recognizes that the motor has generated overcurrent protection. The control chip MCU can further push it to the user's mobile client APP through the WIFI network of the security camera, reminding the user that the motor has reached the limit stuck position, so as to remind the user not to continue to control the motor to rotate in one direction through the APP.

[0036] The present application solves the problem in the prior art of failing to detect and limit motor jams, thereby avoiding the risk of motor damage. It also reduces the difficulty and complexity of the entire structural design, improves the stability and versatility of the system, ensures the safety of the motor, and enhances the user experience by reminding the user.

[0037] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A security camera motor limit position protection circuit, characterized in that: include: A forward control circuit includes a transistor Q3, wherein the base of the transistor Q3 is connected to the first output interface PA1 of the control chip MCU, the collector of the transistor Q3 is connected to the base of the transistor Q1 through a resistor R1, the emitter of the transistor Q3 is grounded, the emitter of the transistor Q1 is connected to a power supply, and the collector of the transistor Q1 is connected to the first end of the motor M1. The transistor Q3 is used to connect the first end of the motor M1 to the high voltage when the first output interface PA1 outputs a high voltage, and to drive the transistor Q6 located between the second end of the motor M1 and the ground end to conduct with the help of the high voltage of the first end, so that the second end of the motor M1 is grounded after passing through the resistor R15; The reverse control circuit includes a transistor Q4, the base of the transistor Q4 is connected to the second output interface PA2 of the control chip MCU, the collector of the transistor Q4 is connected to the base of the transistor Q2 through a resistor R2, the emitter of the transistor Q4 is grounded, the emitter of the transistor Q2 is connected to a power supply, and the collector of the transistor Q2 is connected to the second end of the motor M1. The transistor Q4 is used to connect the second end of the motor M1 to the high voltage when the second output interface PA2 outputs a high voltage, and drive the transistor Q5 located between the first end of the motor M1 and the ground end to conduct with the high voltage of the second end, so that the first end of the motor M1 is grounded after passing through the resistor R15; The rotation locking circuit includes a transistor Q9, a voltage output end of which is grounded after passing through a resistor R7 and the transistor Q9, a control lock output interface LOCKED is provided between the resistor R7 and the collector of the transistor Q9, the control lock output interface LOCKED is connected to the base of the transistor Q3 of the forward control circuit, and the base of the transistor Q4 of the reverse control circuit, the base of the transistor Q9 is connected between the resistor R15 and the motor M1, the emitter of the transistor Q9 is grounded, when the motor M1 rotates normally, the base voltage of the transistor Q9 is insufficient to turn on the transistor Q9, when the motor M1 is stuck, the current flowing through the resistor R15 increases, and the base voltage of the transistor Q9 is increased to turn on the transistor Q9.

2. The security camera motor limit position protection circuit as claimed in claim 1, characterized in that: A resistor R12 and a resistor R13 are provided between the transistor Q9 and the non-grounded end of the resistor R15 . A line between the resistor R12 and the resistor R13 is connected to a first end of the capacitor C1 , and a second end of the capacitor C1 is grounded.

3. The security camera motor limit position protection circuit as claimed in claim 2, characterized in that: The first end of the capacitor C1 is also connected to the non-grounded end of the resistor R15 through the diode D7.

4. The security camera motor limit position protection circuit as claimed in claim 1, characterized in that: The control lock output interface LOCKED is also connected to the third output interface PA3 of the control chip MCU. The control chip MCU is configured to send a signal that the motor M1 is stuck to the host computer when the third output interface PA3 is pulled low.

Images