CN205138644U - Infrared human induction detection circuit of electricity is released to heat - Google Patents

Abstract

The utility model discloses a pyroelectric infrared human body induction detection circuit, which belongs to the field of human body induction detection circuit. A pyroelectric infrared human body induction detection circuit of the utility model is composed of a pyroelectric infrared sensor BH, an in-phase low-pass amplifying circuit, an inverting low-pass amplifying circuit, a comparison circuit, a monostable circuit and a decoupling circuit. The utility model has a simple circuit, is convenient for modularization, has high sensitivity, good reliability, and has a delay function. Once a human body is detected, even if the human body disappears immediately, the circuit output signal will be automatically delayed to ensure that the signal is not lost. wide.

Description

A Pyroelectric Infrared Human Body Induction Detection Circuit

technical field

The utility model relates to a human body induction detection circuit, in particular to a pyroelectric infrared human body induction detection circuit.

Background technique

Some objects in nature radiate infrared thermoelectric energy, such as the sun, lighting, lightning, etc. The infrared wavelengths emitted by them are different. Generally, the wavelength of human body radiation is about 9.4um. The pyroelectric sensor uses a sensitive element made of lead zirconate (PZT) material to sense the temperature change of infrared rays, thereby outputting a weak electrical signal. In addition, an infrared filter is also used on the surface of the sensor. The function of the infrared filter is to select the infrared signal with a wavelength of 7.5 ~ 14um, which can effectively select the infrared radiation of the human body and eliminate the interference infrared of other objects. In fact, pyroelectric The signal output by the sensor is proportional to the rate of change of the infrared radiation temperature, so the pyroelectric sensor is only sensitive to the moving human body. Most of the current pyroelectric sensors are dual-element type, and this structure ensures that the electrical signals generated cancel each other out when the temperature of the element itself changes.

The detection distance of the pyroelectric infrared sensor is only about 1 meter, and after adding the Fresnel optical system, the detection distance can reach 15m. There are three types of optical systems for sensors: incident type, transmissive type, and refractive type. At present, the transmissive type is mainly used in the international market. The optical system can focus the infrared rays radiated from the monitoring space to the sensor, but cannot sensitively reflect changes in these infrared energies. The pyroelectric sensor senses the change value of infrared radiation, rather than the absolute value, and the Fresnel optical system can meet these conditions. The Fresnel optical mirror splits the monitoring space into a series of alternating narrow infrared "sensing areas" and "empty areas" through smooth optical mirror prismatic or columnar processing. When people move in it, some "sensing areas" The infrared rays inside are sometimes absent, so that what the sensor receives is the change value of energy, thus greatly improving the receiving sensitivity. Therefore, it is considered to apply the pyroelectric infrared sensor to the circuit for detecting the human body, so that the circuit for detecting the human body is more sensitive and accurate.

Contents of the invention

1. The technical problems to be solved by the utility model

The purpose of the utility model is to overcome the shortcomings of low sensitivity and accuracy of the existing human body detection circuit, and provide a pyroelectric infrared human body induction detection circuit. The technical scheme of the utility model is adopted, the circuit is simple, and it is convenient for modularization , high sensitivity, good reliability, and has a delay function. Once a human body is detected, even if the human body disappears immediately, the circuit output signal will be automatically delayed to ensure that the signal is not lost. It has a wide range of applications.

2. Technical solution

In order to achieve the above object, the technical solution provided by the utility model is:

A pyroelectric infrared human body induction detection circuit of the present utility model includes a pyroelectric infrared sensor BH, an in-phase low-pass amplifier circuit, an inverting low-pass amplifier circuit, a comparison circuit, a monostable circuit and a decoupling circuit. The pyro-infrared sensor BH is provided with three pins, which are respectively the pin positive power supply end, the pin output end and the pin grounding end; the pin grounding end of the pyro-releasing infrared sensor BH is grounded, and the The positive power supply end of the pin is connected to the positive pole of the power supply through the decoupling circuit and the power supply filter capacitor in turn, and the pin output end of the pyrolysis infrared sensor BH is passed through the in-phase low-pass amplifier circuit, the inverting low-pass amplifier circuit, and the eleventh resistor successively. R11, the comparison circuit, the diode V1 are connected with the monostable circuit.

Furthermore, the decoupling circuit includes a fourth electrolytic capacitor C4, a fifth capacitor C5, and a fifth resistor R5; the non-inverting low-pass amplifier circuit includes a first operational amplifier N1, a second resistor R2, and a third resistor R3, the fourth resistor R4, the second capacitor C2, the third electrolytic capacitor C3, the sixth capacitor C6 and the seventh electrolytic capacitor C7; the inverting low-pass amplifier circuit includes a second operational amplifier N2, a sixth resistor R6, The seventh resistor R7, the eighth resistor R8, the ninth resistor R9, the tenth resistor R10, the eighth electrolytic capacitor C8 and the ninth capacitor C9; the comparison circuit includes a third operational amplifier N3, a twelfth resistor R12, a Thirteen resistors R13 and the tenth electrolytic capacitor C10; the monostable circuit includes the fourth operational amplifier N4, the eleventh electrolytic capacitor C11 and adjustable resistor RP; the pin positive power supply terminal of the pyro-infrared sensor BH Connect to one pole of the fourth electrolytic capacitor C4, one pole of the fifth capacitor and one end of the fifth resistor R5 respectively, the other pole of the fourth electrolytic capacitor C4 and the other pole of the fifth capacitor are grounded, and the fifth resistor R5 The other end of the thirteenth capacitor C13 and one pole of the twelfth capacitor C12 are respectively connected to the positive pole of the power supply, and the other end of the thirteenth capacitor C13 is connected to the other pole of the twelfth capacitor C12 After grounding; the pin output end of the pyroelectric infrared sensor BH is respectively connected to one end of the first resistor R1, one pole of the first capacitor C1 and one end of the second resistor R2, and the other end of the first resistor R1 is connected to the first The other pole of the capacitor C1 is connected to the ground terminal of the pyro-infrared sensor BH, and the other end of the second resistor R2 is respectively connected to one pole of the second capacitor C2 and the non-inverting input terminal of the first operational amplifier N1. The inverting input terminal of an operational amplifier N1 is respectively connected to one end of the third resistor R3, one end of the fourth resistor R4 and one pole of the sixth capacitor C6, and the other end of the third resistor R3 is connected to the third electrolytic capacitor C3 and then connected to The other pole of the second capacitor C2 is connected to the ground, the other end of the fourth resistor R4 is connected to the other pole of the sixth capacitor C6 and then connected to the output terminal of the first operational amplifier N1, and the output terminal of the first operational amplifier N1 is passed through The seventh electrolytic capacitor C7 is connected to one end of the eighth resistor R8, and the other end of the eighth resistor R8 is respectively connected to the inverting input end of the second operational amplifier N2, one end of the tenth resistor R10, and one pole of the ninth capacitor C9, The non-inverting input terminal of the second operational amplifier N2 is respectively connected to one end of the seventh resistor R7, one end of the sixth resistor R6, and one pole of the eighth capacitor C8 through the ninth resistor R9, and the other end of the sixth resistor R6 is connected to the positive pole of the power supply The other end of the seventh resistor R7 is connected to the other pole of the eighth capacitor C8 and then grounded, and the other end of the tenth resistor R10 is connected to the other pole of the ninth capacitor C9 and then connected to the output end of the second operational amplifier N2, The output terminal of the second operational amplifier N2 is connected to the non-inverting input terminal of the third operational amplifier N3 through the eleventh resistor R11, and the inverting input terminal of the third operational amplifier N3 is respectively connected to one of the thirteenth resistor R13. terminal, one end of the twelfth resistor R12 is connected to one pole of the tenth electrolytic capacitor C10, the other end of the twelfth resistor R12 is connected to the positive pole of the power supply, the other end of the thirteenth resistor R13 is connected to the other end of the tenth electrolytic capacitor C10 One pole is grounded respectively, the output terminal of the third operational amplifier N3 is connected with the cathode of the diode V1, the positive pole of the diode V1 is connected with the non-inverting input terminal of the fourth operational amplifier N4, and the non-inverting input terminal of the fourth operational amplifier N4 is connected with the eleventh operational amplifier N4 respectively. One pole of the electrolytic capacitor C11 is connected to one end of the adjustable resistor RP, the other pole of the eleventh electrolytic capacitor C11 is grounded, the other end of the adjustable resistor RP is connected to the positive pole of the power supply, and the inverting input terminal of the fourth operational amplifier N4 is connected to Between the inverting input terminal of the third operational amplifier N3 and the twelfth resistor R12, the output terminal of the fourth operational amplifier N4 outputs a low potential or a high potential.

3. Beneficial effect

Adopting the technical solution provided by the utility model, compared with the existing known technology, has the following beneficial effects:

(1) A kind of pyroelectric infrared human body induction detection circuit of the present utility model, the pin grounding end of its release infrared sensor is grounded, and the pin positive power end of pyroelectric infrared sensor BH passes through decoupling circuit, power filter capacitor and power supply successively The positive pole is connected, and the output terminal of the pyroelectric infrared sensor BH is sequentially connected through the non-inverting low-pass amplifier circuit, the inverting low-pass amplifier circuit, the eleventh resistor R11, the comparison circuit, the diode V1 and the monostable circuit. The circuit is simple and convenient for modules. Chemical, high sensitivity, good reliability;

(2) A kind of pyroelectric infrared human body induction detection circuit of the present utility model, it adopts the decoupling circuit to finely filter the positive electrode of the power supply, so that the pyroelectric infrared sensor BH can obtain a stable DC power supply, and ensure the stable operation of the pyroelectric infrared sensor BH ;

(3) A pyroelectric infrared human body induction detection circuit of the present utility model, which adjusts the delay time by adjusting the adjustable resistance RP, has a delay function, once a human body is detected, even if the human body disappears immediately, the circuit The output signal will be automatically delayed to ensure that the signal is not lost;

(4) A pyroelectric infrared human body induction detection circuit of the present utility model can be used in systems that need to sense human body signals such as automatic energy-saving lamps, anti-theft alarms, automatic doorbells, etc. The time-delayed automatic energy-saving lamp that turns off when people leave the lamp has a wide range of applications.

Description of drawings

Fig. 1 is a schematic diagram of a pyroelectric infrared human body induction detection circuit of the present invention.

detailed description

In order to further understand the content of the utility model, the utility model is described in detail in conjunction with the accompanying drawings and embodiments.

Example

In conjunction with Fig. 1, a pyroelectric infrared human body induction detection circuit of this embodiment includes a pyroelectric infrared sensor BH, an in-phase low-pass amplifier circuit, an inverting low-pass amplifier circuit, a comparison circuit, a monostable circuit and a decoupling circuit , there are three pins on the pyrolytic infrared sensor BH, which are the positive power supply end of the pin, the output end of the pin and the grounding end of the pin; The decoupling circuit and the power supply filter capacitor are connected to the positive pole of the power supply, and the decoupling circuit is used to fine-filter the positive pole of the power supply, so that the pyroelectric infrared sensor BH can obtain a stable DC power supply, ensuring that the pyrolytic infrared sensor BH works stably, and the pyrolytic infrared sensor The pin output terminal of BH is connected to the monostable circuit through the non-inverting low-pass amplifier circuit, the inverting low-pass amplifier circuit, the eleventh resistor R11, the comparison circuit, and the diode V1. The circuit is simple, easy to be modularized, and has high sensitivity and reliability. Good; the specific connection is: the decoupling circuit includes the fourth electrolytic capacitor C4, the fifth capacitor C5 and the fifth resistor R5; the non-inverting low-pass amplifier circuit includes the first operational amplifier N1, the second resistor R2, the third resistor R3, the first Four resistors R4, the second capacitor C2, the third electrolytic capacitor C3, the sixth capacitor C6 and the seventh electrolytic capacitor C7; the inverting low-pass amplifier circuit includes the second operational amplifier N2, the sixth resistor R6, the seventh resistor R7, the Eight resistors R8, ninth resistor R9, tenth resistor R10, eighth electrolytic capacitor C8 and ninth capacitor C9; the comparison circuit includes a third operational amplifier N3, a twelfth resistor R12, a thirteenth resistor R13 and a tenth electrolytic capacitor C10; the monostable circuit comprises the fourth operational amplifier N4, the eleventh electrolytic capacitor C11 and adjustable resistor RP; the pin positive power supply terminal of the pyrolytic infrared sensor BH is connected with one pole of the fourth electrolytic capacitor C4 and the fifth capacitor respectively. One pole is connected to one end of the fifth resistor R5, the other pole of the fourth electrolytic capacitor C4 and the other pole of the fifth capacitor are both grounded, and the other end of the fifth resistor R5 is connected to one pole of the thirteenth capacitor C13, the other end of the fifth capacitor C13, respectively. One pole of the twelfth capacitor C12 is connected to the positive pole of the power supply, the other pole of the thirteenth capacitor C13 is connected to the other pole of the twelfth capacitor C12 and then grounded; the pin output terminal of the pyro-infrared sensor BH Connect to one end of the first resistor R1, one pole of the first capacitor C1 and one end of the second resistor R2 respectively, and connect the other end of the first resistor R1 to the other pole of the first capacitor C1 and then connect to the pyro-infrared sensor BH The other end of the second resistor R2 is respectively connected to one pole of the second capacitor C2 and the non-inverting input end of the first operational amplifier N1, and the inverting input end of the first operational amplifier N1 is respectively connected to the third resistor R3 One end of the fourth resistor R4 is connected to one pole of the sixth capacitor C6, the other end of the third resistor R3 is connected to the third electrolytic capacitor C3 and then connected to the other pole of the second capacitor C2 and grounded, and the fourth resistor The other end of R4 is connected to the other pole of the sixth capacitor C6 and then connected to the output end of the first operational amplifier N1, and the output end of the first operational amplifier N1 passes through the seventh The electrolytic capacitor C7 is connected to one end of the eighth resistor R8, and the other end of the eighth resistor R8 is respectively connected to the inverting input end of the second operational amplifier N2, one end of the tenth resistor R10, and one pole of the ninth capacitor C9. The non-inverting input terminal of the operational amplifier N2 is respectively connected to one end of the seventh resistor R7, one end of the sixth resistor R6, and one pole of the eighth capacitor C8 through the ninth resistor R9, and the other end of the sixth resistor R6 is connected to the positive pole of the power supply. The other end of the seven resistor R7 is connected to the other pole of the eighth capacitor C8 and then grounded, the other end of the tenth resistor R10 is connected to the other pole of the ninth capacitor C9 and then connected to the output end of the second operational amplifier N2, and the second The output terminal of the operational amplifier N2 is connected to the non-inverting input terminal of the third operational amplifier N3 through the eleventh resistor R11, and the inverting input terminal of the third operational amplifier N3 is respectively connected to one end of the thirteenth resistor R13 and one end of the twelfth resistor R12. One end is connected to one pole of the tenth electrolytic capacitor C10, the other end of the twelfth resistor R12 is connected to the positive pole of the power supply, the other end of the thirteenth resistor R13 and the other pole of the tenth electrolytic capacitor C10 are respectively grounded, and the third operation The output terminal of the amplifier N3 is connected with the cathode of the diode V1, and the anode of the diode V1 is connected with the non-inverting input terminal of the fourth operational amplifier N4, and the non-inverting input terminal of the fourth operational amplifier N4 is respectively connected with one pole of the eleventh electrolytic capacitor C11 and can One end of the adjustable resistor RP is connected, the other end of the eleventh electrolytic capacitor C11 is grounded, the other end of the adjustable resistor RP is connected to the positive pole of the power supply, and the inverting input terminal of the fourth operational amplifier N4 is connected to the inverting input terminal of the third operational amplifier N3. Between the phase input terminal and the twelfth resistor R12, the output terminal of the fourth operational amplifier N4 outputs a low potential or a high potential, and the delay time can be adjusted by adjusting the adjustable resistor RP, which has a delay function. Once a human body is detected Appears, even if the human body disappears immediately, the circuit output signal will be automatically delayed to ensure that the signal is not lost. It can be used in automatic energy-saving lamps, anti-theft alarms, automatic doorbells and other systems that need to sense human body signals, especially suitable for applications where a person is on the light , The time-delayed automatic energy-saving lamp that goes out when people leave the lamp has a wide range of applications.

When someone approaches the pyro-infrared sensor BH, the pin output terminal of the pyro-infrared sensor BH outputs a signal u _i , and outputs a signal u _{o2 after the non-inverting low-pass amplifier circuit and the inverting low-pass amplifier circuit, so that the output signal u o2 is} smaller than the comparison When the reference voltage U _REF in the circuit, the output signal u _o3 of the comparison circuit is low potential L, the diode V1 is forward-conducting, so that the eleventh electrolytic capacitor C11 is discharged, and u _o outputs a low potential L; when a person leaves the pyrolytic infrared sensor BH , there is no output signal at the pin output terminal of the pyrolytic infrared sensor BH, the output signal u _o2 is greater than the reference voltage U _REF in the comparison circuit after the non-inverting low-pass amplifier circuit and the inverting low-pass amplifier circuit, and the output signal u _o3 of the comparison circuit outputs a high potential H, the diode V1 is not conducting in the reverse direction, the eleventh electrolytic capacitor C11 is charged, and the charging time depends on the adjustable resistor RP, when the voltage on the eleventh electrolytic capacitor C11 is charged to the reference voltage U _REF , u _o output potential Change from low potential L to high potential H.

A pyroelectric infrared human body induction detection circuit of the utility model has a simple circuit, is convenient for modularization, has high sensitivity, good reliability, and has a delay function. Once a human body is detected, even if the human body disappears immediately, the circuit output signal It will automatically delay to ensure that the signal is not lost, and it has a wide range of applications.

The above schematically describes the utility model and its implementation, which is not restrictive, and what is shown in the accompanying drawings is only one implementation of the utility model, and the actual structure is not limited thereto. Therefore, if a person of ordinary skill in the art is inspired by it, and without departing from the purpose of the invention of the utility model, without creatively designing a structural mode and an embodiment similar to the technical solution, it shall belong to the utility model. protected range.

Claims (2)

1. A pyroelectric infrared human body induction detection circuit is characterized in that: comprise pyroelectric infrared sensor BH, in-phase low-pass amplifying circuit, inverting low-pass amplifying circuit, comparator circuit, monostable circuit and decoupling circuit, all The pyroelectric infrared sensor BH is provided with three pins, which are respectively the pin positive power supply terminal, the pin output terminal and the pin ground terminal; The positive power end of the pin of BH is connected to the positive pole of the power supply successively through the decoupling circuit and the power supply filter capacitor. A resistor R11, a comparison circuit, a diode V1 are connected to the monostable circuit. 2. A pyroelectric infrared human body induction detection circuit according to claim 1, characterized in that: said decoupling circuit comprises a fourth electrolytic capacitor C4, a fifth capacitor C5 and a fifth resistor R5; said The non-inverting low-pass amplifier circuit includes a first operational amplifier N1, a second resistor R2, a third resistor R3, a fourth resistor R4, a second capacitor C2, a third electrolytic capacitor C3, a sixth capacitor C6 and a seventh electrolytic capacitor C7; The inverting low-pass amplifier circuit described above includes a second operational amplifier N2, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eighth electrolytic capacitor C8 and a ninth capacitor C9 ; The comparison circuit includes the third operational amplifier N3, the twelfth resistor R12, the thirteenth resistor R13 and the tenth electrolytic capacitor C10; the described monostable circuit includes the fourth operational amplifier N4, the eleventh electrolytic capacitor C11 and adjustable resistor RP; the pin positive power supply end of the pyrolytic infrared sensor BH is connected to one pole of the fourth electrolytic capacitor C4, one pole of the fifth capacitor and one end of the fifth resistor R5 respectively, and the fourth electrolytic capacitor The other pole of C4 and the other pole of the fifth capacitor are both grounded, and the other end of the fifth resistor R5 is respectively connected to one pole of the thirteenth capacitor C13 and one pole of the twelfth capacitor C12, and then connected to the positive pole of the power supply. The other pole of the thirteenth capacitor C13 is connected to the other pole of the twelfth capacitor C12 and grounded; the pin output end of the pyroelectric infrared sensor BH is respectively connected to one end of the first resistor R1 and one end of the first capacitor C1 pole is connected to one end of the second resistor R2, the other end of the first resistor R1 is connected to the other pole of the first capacitor C1 and then connected to the ground end of the pin of the pyro-infrared sensor BH, and the other end of the second resistor R2 is respectively connected to One pole of the second capacitor C2 is connected to the non-inverting input terminal of the first operational amplifier N1, and the inverting input terminal of the first operational amplifier N1 is respectively connected to one terminal of the third resistor R3, one terminal of the fourth resistor R4 and the terminal of the sixth capacitor C6. One pole is connected, the other end of the third resistor R3 is connected to the third electrolytic capacitor C3 and then connected to the other pole of the second capacitor C2 and grounded, and the other end of the fourth resistor R4 is connected to the other pole of the sixth capacitor C6 Connected to the output end of the first operational amplifier N1, the output end of the first operational amplifier N1 is connected to one end of the eighth resistor R8 through the seventh electrolytic capacitor C7, and the other end of the eighth resistor R8 is respectively connected to the opposite end of the second operational amplifier N2 The phase input end, one end of the tenth resistor R10, and one pole of the ninth capacitor C9 are connected, and the non-inverting input end of the second operational amplifier N2 is respectively connected with one end of the seventh resistor R7, one end of the sixth resistor R6 and the One pole of the eighth capacitor C8 is connected, the other end of the sixth resistor R6 is connected to the positive pole of the power supply, the other end of the seventh resistor R7 is connected to the other pole of the eighth capacitor C8 and grounded, and the other end of the tenth resistor R10 is connected to the positive pole of the power supply. The other pole of the nine capacitors C9 is connected to the output terminal of the second operational amplifier N2, and the output terminal of the second operational amplifier N2 is connected to the non-inverting input terminal of the third operational amplifier N3 through the eleventh resistor R11, The inverting input end of the third operational amplifier N3 is respectively connected to one end of the thirteenth resistor R13, one end of the twelfth resistor R12, and one pole of the tenth electrolytic capacitor C10, and the other end of the twelfth resistor R12 is connected to the positive pole of the power supply The other end of the thirteenth resistor R13 and the other end of the tenth electrolytic capacitor C10 are respectively grounded, the output end of the third operational amplifier N3 is connected to the negative pole of the diode V1, and the positive pole of the diode V1 is in phase with the fourth operational amplifier N4 The input terminal is connected, the non-inverting input terminal of the fourth operational amplifier N4 is respectively connected with one pole of the eleventh electrolytic capacitor C11 and one end of the adjustable resistor RP, the other pole of the eleventh electrolytic capacitor C11 is grounded, and the adjustable resistor RP The other end is connected to the positive pole of the power supply, the inverting input terminal of the fourth operational amplifier N4 is connected between the inverting input terminal of the third operational amplifier N3 and the twelfth resistor R12, and the output terminal of the fourth operational amplifier N4 outputs a low potential or high potential.