CN201126480Y - Hand-hold medium detector - Google Patents
Hand-hold medium detector Download PDFInfo
- Publication number
- CN201126480Y CN201126480Y CNU2007200553471U CN200720055347U CN201126480Y CN 201126480 Y CN201126480 Y CN 201126480Y CN U2007200553471 U CNU2007200553471 U CN U2007200553471U CN 200720055347 U CN200720055347 U CN 200720055347U CN 201126480 Y CN201126480 Y CN 201126480Y
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- electric field
- multivibrator
- hand
- medium detector
- utility
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- 230000005684 electric field Effects 0.000 claims abstract description 35
- 239000000523 sample Substances 0.000 claims abstract description 9
- 230000001939 inductive effect Effects 0.000 claims description 7
- 239000004020 conductor Substances 0.000 claims description 6
- 239000005030 aluminium foil Substances 0.000 claims description 3
- 238000001514 detection method Methods 0.000 abstract description 9
- 230000035945 sensitivity Effects 0.000 abstract description 3
- 229910052782 aluminium Inorganic materials 0.000 description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 8
- 230000010355 oscillation Effects 0.000 description 8
- 239000004411 aluminium Substances 0.000 description 7
- 230000006698 induction Effects 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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Abstract
The utility model discloses a portable medium detector composed of a power supply portion, a case upper cover, a case lower cover, a sensing probe, an electric field detection circuit, a main control CPU and an acousto-optic indication device, which converts the capacitance changes monitored by the sensing probe into frequency changes to realize detection. The portable medium detector is characterized in that, the electric field detection circuit is composed of a grounding electric field multivibrator and a calibration reference multivibrator. The utility model adopts a principle of ''two-path detection, automatic calibration'' to solve the problem of common mode interference due to power supply interference, environment temperature/humidity changes, inconsistency of devices, etc., with low cost, thereby realizing low cost, high sensitivity and strong stability, and further, the utility model is widely applicable for building finishing or the like.
Description
Technical field
The utility model relates to a kind of sniffer, more particularly, relates to a kind of medium that is used for inspected object and forms the detector that whether changes.
Background technology
In existing various types of handheld detecting device, mostly be as the detection of a target, as metal detector etc. at a certain predetermined substance.The product of these types all can't satisfy the requirement that target to be detected is the medium of uncertain type; In addition, in existing various other detection application based on electric field induction principle, although also realized the detection of arbitrary medium is used, but its implementation complexity, particularly wherein because the detection sensitivity that common mode interference caused that factors such as power supply interference, ambient temperature and humidity variation cause is low, the problem of job insecurity, traditional way all is to select for use the high precision components and parts to solve, and causes cost can't effectively reduce all the time.
In the conventional solution, come survey frequency to realize surveying purpose if adopt common RC oscillator to be equipped with elements such as schmitt inverter for reducing cost, can bring a lot of problems: (1) oscillation frequency produces bigger drift with the variation of supply voltage, its reason is, after the threshold voltage of external capacitor and reverser is determined, the variation of supply voltage brings the difference of capacitor charging time, and oscillation frequency is changed.(2) all can there be the characteristic that drift takes place with temperature characterisitic in temperature drift, semiconductor devices, and as the thresholding influence to the reverser internal comparator, this influence is different different because of the device model, and temperature is to the influence of resistance or electric capacity.The temperature coefficient of resistance or electric capacity is depended in this influence.(3) the single-chip microcomputer clock is to the influence of sampling precision, and single-chip microcomputer counts according to own clock, in the regular hour, records the frequency of RC oscillator, if the clock of single-chip microcomputer own exists temperature to float, also can cause the frequency generation error that records, influences measuring accuracy.
The utility model content
The purpose of this utility model provides a kind of simple and convenient, the hand-held medium detector that Effect on Detecting is good.
In order to achieve the above object, the utility model innovation ground proposes the method for " two-way detects; calibration automatically ", guaranteeing that detector is stable, in the time of highly sensitive work, overcome in the application of electric field detection technique ubiquitous with the most cheap current scheme because power supply disturbs, the difficult problem of caused common mode interference such as ambient temperature and humidity variation, by the following technical solutions of the present utility model: a kind of hand-held medium detector, comprise the power supply unit part, outer casing upper cover, the shell lower cover, inductive probe, electric field sensing circuits, master cpu and acousto-optic indicating device are formed, inductive probe is the sense film attached to shell lower cover inboard, sense film and the earth form the electric field loop, electric field sensing circuits is by schmitt inverter integrated circuit block and the resistance that is connected, electric capacity is formed, the acousto-optic indicating device is made up of hummer and light emitting diode, be connected by an electric conductor between inductive probe and the electric field sensing circuits, and after changing the capacitance variations that monitors into frequency change, be connected to master cpu, master cpu is electrically connected with the acousto-optic indicating device, and described electric field sensing circuits is by earth electric field multivibrator and calibration reference multivibrator are formed.
The principle of " two-way detects; calibration automatically " is as follows: the method that adopts two-way to detect simultaneously, different piece with same device, same supply voltage, the resistance capacitance of same temperature coefficient, same single-chip microcomputer clock, even oscillation frequency is with supply voltage, temperature variation and changing, the suffered influence of two-way is in proportion, " calibration automatically " algorithm process by Single Chip Microcomputer (SCM) program (calculates " the frequency calibration factor " by calibration circuit like this, re-use this " frequency calibration factor " and go to revise the measured value of testing circuit), make the frequency change of actual generation only relevant with ground capacitance size variation in the detected circuit, thereby can rely on high precision thereby also expensive device, it is low to have reached the utility model cost, the sensitivity height, the purpose that stability is strong.
More particularly:
Described the earth electric field multivibrator is equipped with corresponding resistance by the U1B door of schmitt inverter and electric capacity is formed.
Described calibration reference multivibrator is equipped with corresponding resistance by the U1E door of schmitt inverter and electric capacity is formed.
Described sense film is an aluminium foil.
Described schmitt inverter is 74HC14,74HC02 or CD4093 etc.
Described light emitting diode is the double-colored positive light emitting diode altogether of tripod, and described hummer is the passive hummer of electromagnetic type.
Compared with prior art, the utlity model has following advantage:
1, it is unqualified to be detected object.Because in the principle of induction of this detector is to realize by the capacitance variations that detects earth electric field, and no matter is metal or metal, conductor still is that insulator all may cause changes in capacitance, thereby the utility model can both be surveyed and obtains.
It when particularly wall-hanging audio-visual equipment installs additional when 2, having satisfied the buildings finishing pointedly firm erecting equipment and needs are sought the new demand of the center of support column or rough ground at body of wall.Along with the further pursuit of people to the living environment comfortableness, must have increasing wall-hanging audio-visual equipment and enter family, providing a cheap and good-quality electronics aid for helping that these equipment are carried out firm installation, also is innovation of the present utility model place.
Description of drawings
Fig. 1 is an one-piece construction synoptic diagram of the present utility model;
Fig. 2 is the circuit theory diagrams of one of them embodiment of the utility model;
Fig. 3 is a primary control program process flow diagram of the present utility model;
Fig. 4 is the product structure synoptic diagram of one of them embodiment of the utility model.
Embodiment
Below in conjunction with drawings and Examples the utility model is further detailed, but the claimed scope of the utility model is not limited to the expressed scope of embodiment.
As shown in Figure 1, medium detector of the present utility model mainly is made up of following ten parts: power supply (two save 1.5V button dry cell), switch, induction aluminium film, electric conductor (taenidium), to earth electric field multivibrator, calibration reference multivibrator, master cpu, dual-colored LED, hummer, calibration reference electric capacity.Induction aluminium film is by about 8 centimetres an of length, and about 2 centimetres of width, the about 1 millimeter composition of thickness are that the aluminium foil of aluminium is formed.
Ground capacitance multivibrator and calibration reference multivibrator are main the structure by common electronic component schmitt inverter, and optionally model comprises 74HC14,74HC04, CD4093 etc.We select 74HC14 for use in the present embodiment.
The range of choice broadness of master cpu: such as the SN8P2501B of SONIX company, the H502Q/HP of HELIOS company or HT48R05A of HOLTEK company or the like all can, select the SN8P2501B of SONIX company in the present embodiment for use.
The each several part annexation is: switch connection dog days direct supply and master cpu, induction aluminium film links to each other with trigger electrode to the earth electric field multivibrator by the conduction taenidium, earth electric field multivibrator, calibration reference multivibrator are all linked to each other with master cpu, and master cpu links to each other with hummer with dual-colored LED.
Principle of work of the present utility model is as follows: induction aluminium film and the earth form earth electric field as the two poles of the earth of electric capacity respectively, behind switch connection power supply and the master cpu, the earth electric field multivibrator is begun starting of oscillation according to this current capacitance to earth electric field, form initial oscillation frequency.The calibration reference multivibrator begins starting of oscillation according to the current capacitance of calibration reference electric capacity, forms initial calibration reference oscillation frequency.System preserves above-mentioned two reference frequencies, begins to monitor in turn the frequency change situation of two-way multivibrator, enters duty.
Be illustrated in figure 2 as the circuit theory diagrams of the utility model embodiment, its annexation is as follows:
Form between induction aluminium film (ANTENNA) and the earth earth electric field; Earth electric field is linked to each other with the 3rd pin of 74HC14 by the conduction taenidium.
Be connected across the electric capacity of the 3rd pin of 74HC14 and the 5.2p between the signal ground and be connected the 3rd pin of 74HC14 and the resistor group of the 510k between the 4th pin electric field multivibrator in couples by the U1B door of 74HC14, earth electric field multivibrator (the 11st pin of a 74HC14) end is passed through conduction taenidium (INDUCTOR) and earth electric field is connected, and the other end links to each other with the 2nd pin of SN8P2501B master cpu.
By the U1E door of 74HC14 be connected the 10th pin of 74HC14 and the resistance of the 510k between the 11st pin is formed the calibration reference multivibrator, calibration reference multivibrator one end (the 11st pin of 74HC14) is that 20p calibration reference electric capacity is connected (other end of this reference capacitance is connected with signal ground) with capacity, and the other end links to each other with the 10th pin of SN802501B master cpu 7.
Hummer links to each other with the 8th pin, the 9th pin of master cpu.Red led in the dual-colored LED drives the 1st pin that pin inserts master cpu, and green indicating lamp drives the 14th pin that pin inserts master cpu.11 pin of SN802501B master cpu link to each other with signal ground.The resistance that resistance of cross-over connection is 1k between common anode in dual-colored LED and the 4th pin of master cpu.The positive pole of power supply links to each other with the 4th pin of master cpu and powers.
Be illustrated in figure 3 as the utility model primary control program process flow diagram.
Be described below in conjunction with the present embodiment step:
1, system powers on, and hummer yowls, and opens the red led of dual-colored LED;
2, measurement is designated as StartValueA to the frequency of earth electric field multivibrator;
3, the requirement according to concrete application scenario is provided with the interval threshold value up and down of other alarm of three levels of ABC, in the present embodiment, the A interval is (0, StartValueA*1/280], the B interval is (StartValueA*1/280, StartValueA*3/280], the C interval be (StartValueA*3/280, StartValueA*9/280];
4, measure the frequency of calibration reference multivibrator, be designated as StartValueB;
5, close hummer, close the dual-colored LED red led, open the dual-colored LED green indicating lamp, system enters major cycle;
6, system monitoring is designated as CurValueA to the frequency of earth electric field multivibrator;
7, the frequency of system monitoring calibration reference multivibrator is designated as CurValueB;
8, calculated rate calibration factor CorrectFactor=CurValueB/StartValueB;
9, frequency of utilization calibration factor calibration CurValueA obtains actual in earth electric field multivibrator frequency RealValueA=CorrectFactor*CurValueA;
10, calculate earth electric field multivibrator oscillation frequency difference DiffValueA=StartValueA-RealValueA;
11, whether the value of judgement DiffValueA falls into three intervals of ABC, and alarms indication, and entering the next round circulation is aforesaid the 6th step, otherwise changes aforesaid the 5th step over to.
The structure of the utility model product as shown in Figure 4, detector mainly is made up of loam cake 1, lower cover 2, main control board 4, battery tray 5, aluminium film 9, electric conductor 3, switch 7, dual-colored LED lamp 8 and hummer 6.The inner wall surface of lower cover 2 is laid layer of aluminum film 9, as inductive probe.One main control board 4 is installed on the lower cover 2, and the left end of lower cover 2 is placed a battery tray 5 and hummer 6, is connected an electric conductor 3 (the utility model employing conduct electricity taenidium) between main control board 4 and the lower cover 2.Loam cake 1 is equipped with switch 7, dual-colored LED lamp 8.
Claims (6)
1. hand-held medium detector, comprise the power supply unit part, outer casing upper cover, the shell lower cover, inductive probe, electric field sensing circuits, master cpu and acousto-optic indicating device are formed, inductive probe is the sense film attached to shell lower cover inboard, sense film and the earth form the electric field loop, electric field sensing circuits adopts schmitt inverter integrated circuit block and the resistance that is connected, electric capacity constitutes, the acousto-optic indicating device is made up of buzzer and light emitting diode, be connected by an electric conductor between inductive probe and the electric field sensing circuits, and after changing the capacitance variations that monitors into frequency change, be connected to master cpu, master cpu is connected with the acousto-optic indicating device, it is characterized in that: described electric field sensing circuits is by earth electric field multivibrator and calibration reference multivibrator are formed.
2. hand-held medium detector according to claim 1 is characterized in that, described the earth electric field multivibrator is equipped with corresponding resistance by the U1B door of schmitt inverter and electric capacity is formed.
3. hand-held medium detector according to claim 1 is characterized in that, described calibration reference multivibrator is equipped with corresponding resistance by the U1E door of schmitt inverter and electric capacity is formed.
4. hand-held medium detector according to claim 1 is characterized in that described sense film is an aluminium foil.
5. according to claim 2 or 3 described hand-held medium detectors, it is characterized in that described schmitt inverter is 74HC14,74HC02 or CD4093.
6. hand-held medium detector according to claim 1 is characterized in that, described light emitting diode is the double-colored positive light emitting diode altogether of tripod, and described hummer is the passive hummer of electromagnetic type.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200553471U CN201126480Y (en) | 2007-08-10 | 2007-08-10 | Hand-hold medium detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200553471U CN201126480Y (en) | 2007-08-10 | 2007-08-10 | Hand-hold medium detector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201126480Y true CN201126480Y (en) | 2008-10-01 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007200553471U Expired - Fee Related CN201126480Y (en) | 2007-08-10 | 2007-08-10 | Hand-hold medium detector |
Country Status (1)
| Country | Link |
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| CN (1) | CN201126480Y (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101509884B (en) * | 2009-03-02 | 2012-07-04 | 北京联合大学 | Grain moisture detector |
| CN103513282A (en) * | 2012-06-25 | 2014-01-15 | 罗伯特·博世有限公司 | Hand-held detector |
| CN106154336A (en) * | 2016-06-28 | 2016-11-23 | 漳州市东方智能仪表有限公司 | A kind of circuit detecting medium below plasterboard and method |
| CN114002515A (en) * | 2021-12-31 | 2022-02-01 | 南京高华科技股份有限公司 | Electric field sensor and preparation method thereof |
-
2007
- 2007-08-10 CN CNU2007200553471U patent/CN201126480Y/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101509884B (en) * | 2009-03-02 | 2012-07-04 | 北京联合大学 | Grain moisture detector |
| CN103513282A (en) * | 2012-06-25 | 2014-01-15 | 罗伯特·博世有限公司 | Hand-held detector |
| CN103513282B (en) * | 2012-06-25 | 2019-01-08 | 罗伯特·博世有限公司 | Hand-held detector |
| CN106154336A (en) * | 2016-06-28 | 2016-11-23 | 漳州市东方智能仪表有限公司 | A kind of circuit detecting medium below plasterboard and method |
| CN106154336B (en) * | 2016-06-28 | 2017-12-12 | 漳州市东方智能仪表有限公司 | The circuit and method of medium below a kind of detection plasterboard |
| CN114002515A (en) * | 2021-12-31 | 2022-02-01 | 南京高华科技股份有限公司 | Electric field sensor and preparation method thereof |
| CN114002515B (en) * | 2021-12-31 | 2022-04-05 | 南京高华科技股份有限公司 | Electric field sensor and preparation method thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20081001 Termination date: 20090910 |