CN206223606U - A kind of miniature PM2.5 sensors - Google Patents

Abstract

The utility model is related to testing equipment technical field, a kind of specifically miniature PM2.5 sensors of PM2.5 suitable for air, including an air chamber, laser generator and circuit board, air chamber upper and lower part is respectively equipped with air inlet and gas outlet, air chamber side is provided with laser generator and diaphragm, air chamber opposite side is provided with the light trapping of pyramidal structure, laser generator launches laser as light source, light scattering phenomenon can occur when passing through air inlet when there is particulate matter, the light intensity of scattering is linear with PM2.5 concentration, the pulse electrical signal for drawing stabilization by signal screening and screening circuit again with change in concentration pulse voltage signal is converted to by the detection of photodiode, and be transferred to signal acquisition and radio transmitter and carry out data acquisition and transmission.Precisely, structure design is compact, low manufacture cost, easy to use, further, can be also combined with electronic gauze mask for present apparatus gathered data, and receives related data by APP ends, obtains real-time PM2.5 concentration values.

Description

A kind of miniature PM2.5 sensors

[technical field]

The utility model is related to testing equipment technical field, and specifically a kind of PM2.5's suitable for air is miniature PM2.5 sensors.

[background technology]

Atmosphere pollution has become the content that entire society pays close attention to jointly.PM2.5 concentration is to evaluate atmospheric pollution level One of key index.Although PM2.5 is the little component of content in earth atmosphere composition, it is to air quality and visibility Etc. there is important influence, compared with thicker Atmospheric particulates, PM2.5 particle diameters are small, and area is big, and activity is strong, easily it is subsidiary it is poisonous, have Evil material (for example, heavy metal, microorganism etc.), and residence time in an atmosphere is long, fed distance is remote, thus to health Influence with atmosphere quality is bigger.

Increasing general public wishes that oneself can be detected to air PM2.5 pollution concentrations.Current PM2.5 inspections Survey mode mainly has weight method, micro oscillation sedimentation balance method, β ray methods and light scattering method.Weight method measurement process is complicated, it is necessary to specialty Personage is operated；Micro oscillation sedimentation balance method and β ray methods can realize automatic measurement, but can not carry out real-time detection, and Instrument price is expensive, and volume ratio is larger, is not suitable for the demand of the civilian detection such as ordinary individual and family.Several production both domestic and external Enterprise is proposed the hand-held PM2.5 detectors that several moneys are based on optical particulate counting principle, and their price is in thousands of units to several Between ten thousand yuan, beyond the expected price of most of personal or families, popularization and application of such product in market are limited.

[utility model content]

The utility model is directed to the problem of existing air PM2.5 pollution, using light scattering principle, using laser as light source A kind of miniature PM2.5 sensors for air PM2.5 detections designed.

To achieve these goals, a kind of miniature PM2.5 sensors, including an air chamber, laser generator and circuit are designed Plate, it is characterised in that air chamber upper and lower part is respectively equipped with air inlet and gas outlet, air chamber side is provided with laser generator and light Door screen, laser generator launches laser as light source, and perforate is respectively equipped with the entering light side of diaphragm inner chamber and light emission side along laser beam, The light trapping that air chamber opposite side is provided with pyramidal structure is used to absorb laser, and gas is entered by the laser beam after diaphragm filtering veiling glare Indoor sample region, when there is particulate matter that light scattering phenomenon can occur when passing through air inlet, light intensity and the PM2.5 concentration of scattering are in line Sexual intercourse, the photodiode on circuit board is converted to change in concentration pulse voltage signal the light intensity in sample region, then passes through Cross signal screening and screening circuit and draw the pulse electrical signal of stabilization, and be transferred to signal acquisition and radio transmitter enters line number According to collection and transmission.

Described signal acquisition and radio transmitter is controlled by chip U4, and No. 1 pin connecting resistance R6 of chip U4 is followed by To the base stage of triode Q1, the colelctor electrode of triode Q1 meets laser triode D3 and is followed by 5V power supplys, and chip U4 is by controlling three poles Pipe Q1 controls Laser emission so that laser tube can be exported according to certain frequency, the grounded emitter of triode Q1, should Chip U4 is used and AD conversion function is carried in BLE-M Bluetooth chips, the chip, and it terminates 3.3V low levels and supplies by No. 8 pin VCC Electricity, No. 15 pins of chip U4 are connected to antenna and are used to carry out wireless data transmission, and No. 12 pins of chip U4 are connected to signal Zhen Not and screening circuit.

Described signal screening is controlled with screening circuit by chip U3, is connected between No. 7 pins and No. 6 pins of chip U3 Resistance R3, another extraction out after one end connects resistance R4 is grounded, and resistance R5, chip are connected between No. 5 pins and No. 2 pins of chip U3 No. 2 pins of U3 are in parallel with No. 1 pin be followed by electric capacity C6 after be grounded, No. 3 pins of chip U3 connect the positive pole of photodiode D2, The laser signal that laser diode D3 launches is converted to and become with concentration by the negative pole ground connection of photodiode D2, photodiode D2 Change pulse voltage signal, No. 12 pins of chip U4 are sent data to by No. 7 pins of chip U3, and extract a termination electricity out Hold C7 filtering.

Opening diameter on the entering light side of described diaphragm and light emission side is 3mm.

The rear end of described light trapping connects with air chamber, and light trapping front end is tapered, so as to form taper for 38 ° is taper Structure, makes to produce refraction to eliminate in pyramidal structure by the laser beam of sample region.

The utility model compared with the existing technology, the advantage is that：Using light scattering principle, using laser as light source, make Veiling glare is filtered by diaphragm, is converted to dense the Concentration Testing of veiling glare with screening circuit through the signal screening on circuit board Degree change pulse voltage signal, and data exchange is carried out using signal acquisition and radio transmitter, the data precision of collection is high, Structure design is compact, low manufacture cost, easy to use；Further, can be also combined with electronic gauze mask, and be received by APP ends Related data, obtain real-time PM2.5 concentration values, air inlet is produced negative pressure, so as to eliminate the fan of air draught so that Miniaturized structure.

[brief description of the drawings]

Fig. 1 is structural representation of the present utility model；

Fig. 2 is air chamber intracavity section schematic diagram of the present utility model；

Fig. 3 is circuit structure connection diagram in the utility model；

Fig. 4 is signal acquisition and radio transmitter figure in the utility model；

Fig. 5 is signal screening and screening circuit figure in the utility model；

Fig. 6 is schematic flow sheet of the present utility model；

In figure：1. the light trapping of 2. laser generator of gas outlet, 3. diaphragm, 4. circuit board, 5. air inlet 6.；

Fig. 1 is specified as Figure of abstract of the present utility model.

[specific embodiment]

The utility model is described in further detail below in conjunction with the accompanying drawings, the structure and principle of this device people professional to this For be very clearly.It should be appreciated that specific embodiment described herein is only used to explain the utility model, and without In restriction the utility model.

Embodiment 1

Referring to Fig. 1 and Fig. 2, the present apparatus includes an air chamber, laser generator and circuit board, and air chamber upper and lower part sets respectively There are air inlet and gas outlet, air chamber side is provided with laser generator and diaphragm, and air chamber opposite side is provided with light trapping, laser generator Transmitting laser, using light scattering principle, can occur light scattering phenomenon as light source when there is particulate matter by air inlet, scattering Light intensity is linear with PM2.5 concentration, is converted to change in concentration pulse voltage signal again by the detection of photodiode The pulse electrical signal of stabilization is drawn by signal screening and screening circuit, and is transferred to signal acquisition and radio transmitter is carried out Data acquisition and transmission.Umber of pulse according to collection carries out the conversion of numerical value according to the given sampling period, by what is collected Numerical value is transmitted according to the form of 16 systems to mobile phone terminal, finally receives related data by APP ends, obtains in real time PM2.5 concentration values.

For mechanism of diaphragm, the present apparatus is respectively equipped with perforate, main effect in the entering light side of diaphragm inner chamber and light emission side For：The perforate of entering light side is filtered more veiling glare, then filters a small amount of veiling glare by the perforate of light emission side, so Allow for light all to be filtered, by a series of this adjustment, the data for collecting substantially can be with reference instrument to upper Number.

Need to timely launch by the laser beam after collection, not interfere with the sampling of internal light, therefore, it is ad hoc The light trapping of tapered structure is counted, has been before this to get in air laser beam in the design, that is, by way of perforate, But natural light can enter into sample region by aperture, the inaccurate of data is caused, because the front end of light trapping is tapered, Make the laser beam for emitting that refraction is produced in pyramidal structure, so as to avoid interference of the light to sample region, while in order to Can make laser beam that refraction just occurs to eliminate, the taper of pyramidal structure is set to 38 ° or so.

The present apparatus is also combined with electronic gauze mask, air inlet is produced negative pressure, so as to eliminate the fan of air draught, so Allow for being minimized in structure, circuit part can be placed on the other position of mouth mask, so that whole volume is more It is compact.

If the dry circuit of corresponding control working sensor is integrated with the circuit board in the present apparatus, including Power convert electricity Road, signal acquisition and radio transmitter, operational amplification circuit, signal screening and screening circuit etc., circuit connection diagram ginseng See Fig. 3, circuit workflow schematic diagram is referring to 6.Wherein power-switching circuit be will be input into voltage to each chip work Voltage as power supply, due to the known circuits more than the power-switching circuit in the present apparatus using the art, herein not Repeat, optical circuit part in the present apparatus is described emphatically below, optical circuit part is mainly adopted including circuit signal Collection and radio transmitter, signal screening and screening circuit.

The circuit theory diagrams of signal acquisition and radio transmitter are mainly controlled referring to Fig. 4 by chip U4, and chip U4 is used BLE-M Bluetooth chips, carry AD conversion inside BLE-M, AD conversion chip can be saved by the AD conversion function of carrying so that Circuit is more succinct, and the specific attachment structure of its circuit is：No. 1 pin connecting resistance R6 of chip U4 is followed by triode Q1's Base stage, the colelctor electrode of triode Q1 meets laser triode D3 and is followed by 5V power supplys, and chip U4 controls laser by controlling triode Q1 Transmitting so that laser tube can be exported according to certain frequency, realize the requirement of low-power consumption, and the emitter stage of triode Q1 connects Ground, the chip terminates 3.3V power at very low levels by No. 8 pin VCC, and No. 15 pins of chip U4 are connected to antenna and are used to carry out wirelessly Data is activation, No. 12 pins of chip U4 are connected to signal screening and screening circuit.

Referring to Fig. 5, the electric router chip U3 is controlled the circuit theory diagrams of signal screening and screening circuit, No. 7 of chip U3 Resistance R3 is connected between pin and No. 6 pins, another one end of extracting out connects ground connection after resistance R4, No. 5 pins of chip U3 and No. 2 pipes Be connected to resistance R5 between pin, No. 2 pins of chip U3 are in parallel with No. 1 pin be followed by electric capacity C6 after be grounded, No. 3 pins of chip U3 The positive pole of photodiode D2 is connect, the negative pole ground connection of photodiode D2, photodiode D2 launches laser diode D3 Laser signal is converted to change in concentration pulse voltage signal, takes PM2.5 passage numerical value, by No. 7 pins of chip U3 by number According to No. 12 pins transmitted to chip U4, and extract termination capacitor C7 filtering out.

Claims (5)

1. a kind of miniature PM2.5 sensors, including an air chamber, laser generator and circuit board, it is characterised in that air chamber top and Bottom is respectively equipped with air inlet and gas outlet, and air chamber side is provided with laser generator and diaphragm, and laser generator transmitting laser is made It is light source, perforate is respectively equipped with the entering light side of diaphragm inner chamber and light emission side along laser beam, air chamber opposite side is provided with pyramidal structure Light trapping be used to absorb laser, the sample region entered in air inlet chamber of laser beam after diaphragm filtering veiling glare, when there is particle Thing passes through that light scattering phenomenon can occur during air inlet, and the light intensity of scattering is linear with PM2.5 concentration, the photoelectricity on circuit board Diode is converted to change in concentration pulse voltage signal the light intensity in sample region, then is obtained with screening circuit by signal screening Going out the pulse electrical signal of stabilization, and be transferred to signal acquisition and radio transmitter carries out data acquisition and transmission.

2. a kind of miniature PM2.5 sensors as claimed in claim 1, it is characterised in that described signal acquisition and wireless transmission Electric router chip U4 controls, No. 1 pin connecting resistance R6 of chip U4 is followed by the base stage of triode Q1, the colelctor electrode of triode Q1 Meet laser triode D3 and be followed by 5V power supplys, chip U4 controls Laser emission by controlling triode Q1 so that laser tube can be by Exported according to certain frequency, the grounded emitter of triode Q1, chip U4 uses BLE-M Bluetooth chips, in the chip With AD conversion function, it terminates 3.3V power at very low levels by No. 8 pin VCC, and No. 15 pins of chip U4 are connected to antenna and are used to Wireless data transmission is carried out, No. 12 pins of chip U4 are connected to signal screening and screening circuit.

3. a kind of miniature PM2.5 sensors as claimed in claim 1, it is characterised in that described signal screening and screening circuit Controlled by chip U3, chip U3 uses LM358 chips, is connected to resistance R3 between No. 7 pins and No. 6 pins of chip U3, separately Extract out after one end connects resistance R4 and be grounded, resistance R5, No. 2 pipes of chip U3 are connected between No. 5 pins and No. 2 pins of chip U3 Pin is in parallel with No. 1 pin be followed by electric capacity C6 after be grounded, No. 3 pins of chip U3 connect the positive pole of photodiode D2, the pole of photoelectricity two The negative pole ground connection of pipe D2, photodiode D2 is converted to change in concentration pulse electricity the laser signal that laser diode D3 launches Pressure signal, No. 12 pins of chip U4 is sent data to by No. 7 pins of chip U3, and extract termination capacitor C7 filters out Ripple.

4. a kind of miniature PM2.5 sensors as claimed in claim 1, it is characterised in that the entering light side of described diaphragm and light extraction Opening diameter on side is 3mm.

5. a kind of miniature PM2.5 sensors as claimed in claim 1, it is characterised in that the rear end of described light trapping and air chamber Connect, light trapping front end is tapered, so as to form taper for 38 ° is pyramidal structure, make the laser beam by sample region in taper Refraction is produced to eliminate in structure.