CN100565247C - Long distance intelligent metal detector - Google Patents
Long distance intelligent metal detector Download PDFInfo
- Publication number
- CN100565247C CN100565247C CNB2007100677642A CN200710067764A CN100565247C CN 100565247 C CN100565247 C CN 100565247C CN B2007100677642 A CNB2007100677642 A CN B2007100677642A CN 200710067764 A CN200710067764 A CN 200710067764A CN 100565247 C CN100565247 C CN 100565247C
- Authority
- CN
- China
- Prior art keywords
- circuit
- signal
- chip microcomputer
- wave
- metal detector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Abstract
The present invention relates to long distance intelligent metal detector and comprise AVR single-chip microcomputer intelligent decision and interactive system (1) etc., single-chip microcomputer produces square wave behind wave mode conversion frequency-selecting power amplifier synthetic circuit (5), sets up electromagnetic field by transmitting winding group (2); Receiving coil (3) acquired signal is organized into controlled effective value level by switching mode modulation effective value low-pass filtering synthetic circuit (6) after accepting circuit (4), obtain voltage signal easy to identify by IU change-over circuit (7); System (1) is judged this voltage signal; Datum keeps and drift compensation integration circuit (8) provides comparative level for IU change-over circuit (7), and drift compensates to signal; Negative supply Voltage stabilizing module formula complete machine power circuit (10) provides operating voltage.Metal detector of the present invention is realized intelligent parameter adjustment, and has improved the stability and the anti-interference of metal detector; Also have low cost, circuit is simple, detection range is big advantage.
Description
Technical field
The invention belongs to nondestructive electromagnetic detection technique field, particularly a kind of long distance intelligent metal detector based on the AVR single-chip microcomputer.
Background technology
Metal detector is widely used in each Detection Techniques field, and according to ultimate principle and detection line, it can be divided into beat type, auto-excited induction-type, power absorption formula and balanced type.Usually adopt balanced type at present, such metal detector can obtain higher sensitivity, and the accuracy of detection height also has the big advantage of measuring distance.Adopt the balanced type metal detector of complete mimic channel initiatively to be produced by mimic channel and transmit, comparator circuit generation modulated square wave, display are pointer-type millivolt gauge outfit.Though, adopt the metal detector of complete mimic channel to have the advantage that circuit is simple, function easily realizes, adopt the metal detector of mimic channel to have many shortcomings such as anti-interference is poor, stability is weak, difficulty of parameter tuning.
Domestic and international patent or patented claim about intelligent metal detector, as U.S. Patent number 5786696, denomination of invention: METAL DETECTOR FOR IDENTIFYING TARGET ELECTRICALCHARACTERISTICS, DEPTH AND SIZE (can survey the metal detector of the metal object classification and the degree of depth and size), Chinese patent application numbers 200410067572.8, name is called intelligent metal detector, and the technical scheme of above-mentioned patent or patented claim all adopts the digitization program of expensive dsp chip and single-chip microcomputer to overcome and adopts the existing shortcoming of mimic channel metal detector.But all there is the shortcoming of cost height, circuit complexity in above-mentioned two technical schemes.
Summary of the invention
The invention provides the intelligent metal detector that a kind of cost is low, circuit simple, the detection distance is big based on the AVR single-chip microcomputer.
The technical solution used in the present invention: long distance intelligent metal detector comprises AVR single-chip microcomputer intelligent decision and interactive system (1), transmitting winding group (2), receiving coil (3), receiving circuit (4), wave mode conversion frequency-selecting power amplifier synthetic circuit (5), switching mode modulation effective value low-pass filtering synthetic circuit (6), current-to-voltage converting circuit (7), datum maintenance and drift compensation integration circuit (8), negative supply Voltage stabilizing module formula complete machine power circuit (10);
The AVR single-chip microcomputer produces square-wave signal after wave mode conversion frequency-selecting power amplifier synthetic circuit (5) is handled, and sets up electromagnetic field by transmitting winding group (2) emission;
The signal that receiving coil (3) is gathered is after accepting circuit (4) adjustment, be organized into controlled effective value level by switching mode modulation effective value low-pass filtering synthetic circuit (6), at the drift situation of this effective value level, handle to obtain big voltage signal easy to identify by current-to-voltage converting circuit (7); AVR single-chip microcomputer intelligent decision and interactive system (1) can be selected different mode of operations, and according to corresponding work mode this big voltage signal are judged, demonstrate to have or not metal or judged results such as metal types, size on liquid crystal;
Datum keeps and drift compensation integration circuit (8) is that current-to-voltage converting circuit (7) provides the comparative level under the designated environment, and the drifts of signal slowly that factor produced such as instrument temperature variation are compensated;
Negative supply Voltage stabilizing module formula complete machine power circuit (10) provides the complete machine operating voltage.
Described long distance intelligent metal detector also comprises sound circuit (9), and this sound circuit (9) is the power amplifier of a frequency variation signal, and sound frequency is associated with the magnitude of voltage of current-to-voltage converting circuit (7) output.
Described long distance intelligent metal detector, transmitting winding group (2) is made up of the transmitting coil that varies in size, two transmitting coils are the inside and outside both sides that asymmetric is distributed in receiving coil (3), and little transmitting coil is concentric with receiving coil, big transmitting coil and receiving coil off-centre.
Described long distance intelligent metal detector, select one of AVR ATmega series monolithic for use, carry non-volatile program and data storage cell in this single-chip microcomputer, has the online programming ability, carry ten AD modular converters, two-way PWM functional module and multichannel IO, it forms AVR single-chip microcomputer intelligent decision and interactive system (1) with dot matrix or character mode lcd, keyboard very easily;
Single-chip microcomputer exports three tunnel (A ', B ', C ') square-wave signal, receive two-way (D ', E ') DC level switching signal, (F ') the audio frequency frequency variation signal of exporting one tunnel, (the G ') digital level of exporting a tunnel is as the gating switch signal of the two-way low-pass filter signal in the switching mode modulation effective value low-pass filtering synthetic circuit (6); Keyboard exports one the tunnel, and (H ') datum keeps and the required reset signal of drift compensation integration circuit (8).
The square wave of described long distance intelligent metal detector, single-chip microcomputer produce one tunnel (A ') 5～200KHz is converted to sine wave by wave mode conversion frequency-selecting power amplifier synthetic circuit (5), to external emission, sets up electromagnetic field through transmitting winding group (2).
Described long distance intelligent metal detector, wave mode conversion frequency-selecting power amplifier synthetic circuit (5) comprises mutual inductor, triode, magnetic core inductance, resistance R 11, resistance R 12, capacitor C 11, capacitor C 12, a road (A ') square wave that single-chip microcomputer produces carries out the frequency-selecting power amplification by this circuit (5), converts sine wave to and is sent to emitting antenna.
Described long distance intelligent metal detector, switching mode modulation effective value low-pass filtering synthetic circuit (6) comprises amplifier A, B, C, D, integrated circuit CD4053, resistance R 1, R2, R3, R4, R5, R6, R7, R8, R9, R10, capacitor C 1, C2, C3, C4, C5, C6, AC signal is introduced by capacitor C 1, DC level is exported by D ' level signal end, the break-make sequential of the two-way that single-chip microcomputer produces (B ', C ') square-wave signal operating electronic switch, the channel selecting signal of generation is handled the synthetic of two-way integration level.
Described long distance intelligent metal detector, datum keeps and single amplifier, capacitor C 21, resistance R 26, R27, the R22 of drift compensation integration circuit (8) form integrator, dual comparator LM393, resistance R 20, R21, R22, R23, R24, R25, diode D1, D2 form the bucking voltage reverse circuit, and resistance R 28, R29, R30, R31, R32, diode D3, D4, D5, capacitor C 22, RESET keyswitch, negative supply and field effect transistor are formed strong compensation comparative level and followed on-off circuit.
According to Theory of Electromagnetic Field, the alternating magnetic field that two transmitting coils produce produces the induction electromotive force of a same frequency, anti-phase, spread respectively in receiving coil, and both disappear mutually and promptly form receiving balance.Metal in alternating magnetic field will be because eddy effect or magnetic effect will produce a complementary field, and the magnetic line of force that destroys primary field distributes, and this complementary field is called secondary field again.Eddy effect is relevant with conductivity, and magnetic effect is relevant with magnetic permeability.The secondary field that metal target produced can make the size of electric current in the receiving coil and phase place change.The non-ferromagnetic metal conductivity is bigger, and it comprises paramagnet and diamagnet, paramagnet such as titanium, manganese, and diamagnet such as gold, silver can think to conduct electricity non-magnetic material, mainly produce eddy effect; The ferromagnetic metal magnetoconductivity is very big, and as iron, nickel, cobalt, conductivity is also bigger, can think promptly to conduct electricity and magnetic conduction substance, mainly produces magnetic effect, and eddy effect is arranged again simultaneously.The secondary field that the metal of dissimilar metals or different size, shape produces is to the difference that influences of primary field.Therefore, can judge whether to exist metal or judge the metal classification and by signal Processing to receiving coil with the size of metalloid.
AVR single-chip microcomputer of the present invention sends three the tunnel with out-phase square-wave signals frequently, and the Third Road square wave phase can intelligence be adjusted, and three road square waves are respectively applied for and transmit and the extraction of received signal effective value.The present invention carries out the voltage effective value conversion by the signal to receiving coil, relatively have or not the effective value that influences secondary electrical field, current-to-voltage converting circuit can be obtained the conversion of volt/receive volt step voltage, whether has metal or judges the metal classification and with the size of metalloid according to the difference intelligent decision of effective value.
Metal detector of the present invention have the ground balance, greater than, equal three kinds of mode of operations.The ground balanced mode balances the secondary field influence of environment.Under the ground balanced mode, remembering state value under the environmental impact automatically by the reset key instrument under the no metallic state.When the different secondary field is detected, judge whether there is metal and judges the metal classification by comparing the original state value.Greater than, equal pattern and be used for fixing the interior identification of distance with the work of metalloid size.Greater than, equal under two kinds of patterns by the state value under the strong instrument memory standard metal piece influence that resets.When the different secondary field is detected, by comparing the size of original state value intelligent decision with metalloid.
Metal detector of the present invention adopts AVR single-chip microcomputer digital technology to combine with mimic channel, adopt the AVR single-chip microcomputer to finish the man-machine conversation function simultaneously, realize intelligent parameter adjustment, and improved the stability and the anti-interference of metal detector, fundamentally changed the defective that adopts complete Analogical Circuit Technique scheme; The present invention also has low cost, circuit is simple, detection range is big advantage.
Metal detector of the present invention can be used for underground metal detection, underground utilities detection, physics mine locating, be applicable to that also all need detect the industry of metal object, as food, medicine, weaving, clothes, toy etc., the metallic particles that can will sneak into wherein detects, and guarantees the safety of food, the person and engineer operation.
Description of drawings
Fig. 1 is the system chart based on the long distance intelligent metal detector of AVR single-chip microcomputer.
Fig. 2 is switching mode modulation effective value low-pass filtering synthetic circuit.
Fig. 3 is wave mode conversion frequency-selecting power amplifier synthetic circuit.
Fig. 4 keeps and drift compensation integration circuit for datum.
Embodiment
Below in conjunction with accompanying drawing the embodiment of the invention is elaborated.
As shown in Figure 1, select one of AVR ATmega series monolithic for use, carry non-volatile program and data storage cell in the single-chip microcomputer, has the online programming ability, carry ten AD modular converters, two-way PWM functional module and multichannel IO mouth, it connects dot lcd or character mode lcd and input keyboard very easily and forms AVR single-chip microcomputer intelligent decision and interactive system 1.The AVR single-chip microcomputer produces A ', B ', C ' three tunnel with frequency out-phase square wave, the fixed value in the selected 5 ~ 200KHz scope of frequency.A ' road square wave is set up the fixed electromagnetic field of a relative weighing apparatus by transmitting winding group 2 emissions after converting sine wave to through wave mode conversion frequency-selecting power amplifier synthetic circuit 5.Transmitting winding group 2 is made up of two coils that differ in size, and big small coil is the inside and outside both sides that asymmetric is distributed in receiving coil 3, and little transmitting coil is concentric with receiving coil, big transmitting coil and receiving coil off-centre.B ' road square wave be one with receive electromagnetic wave and fix the square wave of 45 degree phase shifts, C ' road square wave be one with receive the electromagnetic wave phase place the adjustable square wave of 0 to 180 degree phase differential arranged, B ', C ' two-way square wave enter the break-make that switching mode modulation effective value low-pass filtering synthetic circuit 6 is handled modulation switch.The electromagnetic wave signal that receiving coil 3 is gathered is by receiving circuit 4, a controlled dc level signal D ' of switching mode modulation effective value low-pass filtering synthetic circuit 6 back arrangements becoming, dc level signal D ' again through the I/U change-over circuit be current-to-voltage converting circuit 7 be converted into deviate from current potential be subjected to metal to influence institute with electromagnetic field to the relevant d. c. voltage signal E ' of variation, d. c. voltage signal E ' is a big voltage signal easy to identify.Datum keeps and drift compensation integration circuit 8 provides the datum of the comparison under the designated environment for current-to-voltage converting circuit 7, and the slow signal drift that factors such as detector temperature variation are produced compensates.1 couple of D ' of AVR single-chip microcomputer intelligent decision and interactive system, E ' magnitude of voltage carry out the AD conversion, judge according to two numerical value to have or not metal, metal types, metal size, or in operating process, C ' road square wave is chosen the phase adjusted value so that instrument is applicable to the work on the spot environment.AVR single-chip microcomputer intelligent decision and interactive system 1 provide a prompting liquid crystal display keyboard operation system clear and definite, easy and simple to handle for the user, and liquid crystal display is used for display graphics, literal, thereby realize intelligent control.Sound circuit 9 is the power amplifier of a frequency variation signal, and sound frequency is relevant with the magnitude of voltage of current-to-voltage converting circuit 7 outputs, is used for the voice suggestion when judging the qualified metal of appearance.The whole power circuit 10 of negative supply Voltage stabilizing module formula is handled nine volts of battery direct supplys, provides complete machine five couchers to make voltage and the required negative voltage of reset switch.
Be illustrated in figure 2 as wave mode conversion frequency-selecting power amplifier synthetic circuit 5.A ' the road square wave that the AVR single-chip microcomputer produces is imported by R11, resistance R 11, R12, pliotron, capacitor C 11, mutual inductor and power vd D constitute basic transistor collector power amplification circuit, the square-wave signal power amplification of A ' road is exported, inductance C1, C2, capacitor C 11 constitute the LC frequency selection circuit, select with the frequency sine-wave signal, capacitor C 12 and the magnetic core inductance sine wave signal after with power amplification exports emitting antenna to and sets up electromagnetic field.
Be illustrated in figure 3 as switching mode modulation effective value low-pass filtering synthetic circuit 6.By circuit diagram as can be known, capacitor C 1 will be handled the AC signal that obtains through receiving coil and receiving circuit and be coupled to two amplifier A, B.A is that in-phase signal is followed, and B is that out-phase is followed.The output of amplifier A enters X0, the Y0 passage of electronic switch.The output of amplifier B enters X1, the Y1 passage of electronic switch, and the break-make of being controlled electronic switch by B ', C ' two-way square wave is to obtain the level signal D ' of different sizes.The channel selecting signal of electronic switch is used for controlling the break-make of electronic switch Z0, to select the detector operation pattern.When Z0 disconnects, be ground balance mode of operation; When the Z0 conducting, for greater than, equal mode of operation.Amplifier C and resistance R 3, R5, R6, R7 and capacitor C 2, C3 constitute one road effective value low-pass filter circuit, amplifier D and resistance R 4, R8, R9 and capacitor C 4, C5, C6 constitute another road effective value low-pass filter circuit, two-way effective value low-pass filter circuit signal can synthesize mutually, and modulation front end input signal is handled and obtained level signal D '.
Being illustrated in figure 4 as datum keeps and drift compensation integration circuit 8.Single amplifier and capacitor C 21, resistance R 26, R27, R22 form integrator, dual comparator LM393 and resistance R 20, R21, R22, R23, R24, R25, diode D1, D2 form the bucking voltage reverse circuit, and resistance R 28, R29, R30, R31, R32, diode D3, D4, D5, capacitor C 22, RESET keyswitch, negative supply and field effect transistor are formed strong compensation comparative level and followed on-off circuit.The output signal that is input as current-to-voltage converting circuit 7 of this circuit, this signal is relevant with the output signal of this circuit.The RESET keyswitch is connected, when the output signal of current-to-voltage converting circuit 7 relatively in current potential be timing, the rising of this circuit output signal level forward; Otherwise when the output signal of current-to-voltage converting circuit 7 relatively in current potential when negative, this circuit output signal level negative sense descends, influence the output signal of current-to-voltage converting circuit 7, make the middle relatively current potential of output signal of current-to-voltage converting circuit 7 drop to isoelectric, this moment, compensation put in place.After the RESET keyswitch disconnected, comparative level got and keeps.Because the variation of metal detector surrounding environment factor, under the interference of no metal object, the drift of trace also will appear in the output signal of current-to-voltage converting circuit 7, with dual comparator LM393 is that the bucking voltage reverse circuit that core is formed has carried out micro-compensation to comparing level, keeps the stability of detector.
Metal detector of the present invention produces the metal detector of different detection ranges under employing varies in size the configuration of antenna bay, promptly can design series of products.As detecting distance, under noiseless site environment, can be divided into 1.50 meters, 3.00 meters, 4.50 meters, 6.00 meters types in the maximum induction of 600mm * 600mm * 6mm steel plate.
Claims (8)
1, metal detector, comprise transmitting winding group (2), receiving coil (3), receiving circuit (4), it is characterized in that: also comprise AVR single-chip microcomputer intelligent decision and interactive system (1), wave mode conversion frequency-selecting power amplifier synthetic circuit (5), switching mode modulation effective value low-pass filtering synthetic circuit (6), current-to-voltage converting circuit (7), datum maintenance and drift compensation integration circuit (8), negative supply Voltage stabilizing module formula complete machine power circuit (10);
The AVR single-chip microcomputer produces square-wave signal after wave mode conversion frequency-selecting power amplifier synthetic circuit (5) is handled, and sets up electromagnetic field by transmitting winding group (2) emission;
The signal that receiving coil (3) is gathered is after accepting circuit (4) adjustment, be organized into controlled effective value level by switching mode modulation effective value low-pass filtering synthetic circuit (6), at the drift situation of this effective value level, handle to obtain big voltage signal easy to identify by current-to-voltage converting circuit (7); AVR single-chip microcomputer intelligent decision and interactive system (1) are judged this big voltage signal according to corresponding work mode, and are shown judged result;
Datum keeps and drift compensation integration circuit (8) is that current-to-voltage converting circuit (7) provides the comparative level under the designated environment, and the drift of signal slowly that produces is compensated;
Negative supply Voltage stabilizing module formula complete machine power circuit (10) provides the complete machine operating voltage.
2, metal detector according to claim 1 is characterized in that: also comprise sound circuit (9), sound circuit (9) is the power amplifier of a frequency variation signal, and sound frequency is associated with the magnitude of voltage of current-to-voltage converting circuit (7) output.
3, metal detector according to claim 1, it is characterized in that: transmitting winding group (2) is made up of the transmitting coil that varies in size, two transmitting coils are the inside and outside both sides that asymmetric is distributed in receiving coil (3), little transmitting coil is concentric with receiving coil, big transmitting coil and receiving coil off-centre.
4, metal detector according to claim 1 is characterized in that: select one of AVR ATmega series monolithic for use, with dot matrix or character mode lcd, keyboard composition AVR single-chip microcomputer intelligent decision and interactive system (1);
Single-chip microcomputer exports three tunnel (A ', B ', C ') square-wave signal, receive two-way (D ', E ') DC level switching signal, (F ') the audio frequency frequency variation signal of exporting one tunnel, (the G ') digital level of exporting a tunnel is as the gating switch signal of the two-way low-pass filter signal in the switching mode modulation effective value low-pass filtering synthetic circuit (6); Keyboard exports one the tunnel, and (H ') datum keeps and the required reset signal of drift compensation integration circuit (8).
5, according to claim 1 or 3 or 4 described metal detectors, it is characterized in that: the square wave of single-chip microcomputer produces one tunnel (A ') 5～200KHz is converted to sine wave by wave mode conversion frequency-selecting power amplifier synthetic circuit (5), to external emission, set up electromagnetic field through transmitting winding group (2).
6, according to claim 1 or 4 described metal detectors, it is characterized in that: wave mode conversion frequency-selecting power amplifier synthetic circuit (5) comprises mutual inductor, triode, magnetic core inductance, resistance R 11, resistance R 12, capacitor C 11, capacitor C 12, a road (A ') square wave that single-chip microcomputer produces carries out the frequency-selecting power amplification by this circuit (5), converts sine wave to and is sent to emitting antenna.
7, according to claim 1 or 4 described metal detectors, it is characterized in that: switching mode modulation effective value low-pass filtering synthetic circuit (6) comprises amplifier A, B, C, D, integrated circuit CD4053, resistance R 1, R2, R3, R4, R5, R6, R7, R8, R9, R10, capacitor C 1, C2, C3, C4, C5, C6, AC signal is introduced by capacitor C 1, DC level is exported by D ' level signal end, the break-make sequential of the two-way that single-chip microcomputer produces (B ', C ') square-wave signal operating electronic switch, the channel selecting signal of generation is handled the synthetic of two-way integration level.
8, according to claim 1 or 4 described metal detectors, it is characterized in that: datum keeps and single amplifier, capacitor C 21, resistance R 26, R27, the R22 of drift compensation integration circuit (8) form integrator, dual comparator LM393, resistance R 20, R21, R22, R23, R24, R25, diode D1, D2 form the bucking voltage reverse circuit, and resistance R 28, R29, R30, R31, R32, diode D3, D4, D5, capacitor C 22, RESET keyswitch, negative supply and field effect transistor are formed strong compensation comparative level and followed on-off circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007100677642A CN100565247C (en) | 2007-03-26 | 2007-03-26 | Long distance intelligent metal detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007100677642A CN100565247C (en) | 2007-03-26 | 2007-03-26 | Long distance intelligent metal detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101025442A CN101025442A (en) | 2007-08-29 |
| CN100565247C true CN100565247C (en) | 2009-12-02 |
Family
ID=38743919
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2007100677642A Expired - Fee Related CN100565247C (en) | 2007-03-26 | 2007-03-26 | Long distance intelligent metal detector |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100565247C (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2570824B1 (en) * | 2011-09-19 | 2017-03-08 | Mettler-Toledo Safeline Limited | Method for operating a metal detection apparatus and apparatus |
| EP2629121B1 (en) | 2012-02-17 | 2016-04-06 | Mettler-Toledo Safeline Limited | Metal detector for production and packaging lines |
| CN103713328A (en) * | 2013-12-27 | 2014-04-09 | 天津森宇科技发展有限公司 | City underground pipeline construction detection device based on electromagnetic induction technology |
| EP3182170B1 (en) * | 2015-12-17 | 2023-09-27 | Mettler-Toledo Safeline Limited | Metal detection apparatus and method for operating a metal detection apparatus |
| CN109932752A (en) * | 2017-12-15 | 2019-06-25 | 蒋伟 | A kind of metal detector |
| CN108444463A (en) * | 2017-12-21 | 2018-08-24 | 中国船舶重工集团公司第七0七研究所 | A kind of digital closed-loop optic fiber gyroscope circuit inhibiting spike asymmetry |
| CN109932750A (en) * | 2019-04-15 | 2019-06-25 | 王开 | A kind of metal detection sensing integrated circuit and metal detection sensor circuit |
| CN112531919B (en) * | 2020-12-01 | 2023-05-26 | 中色科技股份有限公司 | Wireless power supply circuit for industrial detection equipment |
| CN113900148B (en) * | 2021-09-15 | 2023-09-12 | 上海微波技术研究所（中国电子科技集团公司第五十研究所） | Multi-frequency metal detector and metal target identification method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU8981682A (en) * | 1979-01-29 | 1983-04-14 | Garrett Electronics Inc. | Metal detector with mode selection |
| GB2049943B (en) * | 1979-03-05 | 1984-01-25 | Harco Corp | Electrical survey apparatus |
| DE102005018590A1 (en) * | 2005-04-21 | 2006-12-07 | Mesutronic Gerätebau GmbH | Metal detector for monitoring unwanted metallic particles in product e.g. food, flow, has circuit stage assigned to sensor signal, and reducing amplification to small valve during exceeding of value dependent on permissible maximum value |
-
2007
- 2007-03-26 CN CNB2007100677642A patent/CN100565247C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU8981682A (en) * | 1979-01-29 | 1983-04-14 | Garrett Electronics Inc. | Metal detector with mode selection |
| GB2049943B (en) * | 1979-03-05 | 1984-01-25 | Harco Corp | Electrical survey apparatus |
| DE102005018590A1 (en) * | 2005-04-21 | 2006-12-07 | Mesutronic Gerätebau GmbH | Metal detector for monitoring unwanted metallic particles in product e.g. food, flow, has circuit stage assigned to sensor signal, and reducing amplification to small valve during exceeding of value dependent on permissible maximum value |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101025442A (en) | 2007-08-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100565247C (en) | Long distance intelligent metal detector | |
| CN201037870Y (en) | Metal detector | |
| CN105182427B (en) | A kind of metal sensor | |
| CN205139229U (en) | Huge magnetoresistive effect current sensor | |
| CN102298159B (en) | Metal detector | |
| CN107462758A (en) | A kind of closed-loop current sensors | |
| CN205210163U (en) | Huge magnetoresistive effect current sensor | |
| CN201837683U (en) | High-precision alternating-current impedance testing device | |
| CN201796014U (en) | Metal material analyzer | |
| CN208421051U (en) | A kind of leakage current sensor | |
| CN101397907A (en) | Method and apparatus for eliminating directly coupling signal of induction logging tool | |
| CN102859873A (en) | Locator | |
| CN104481519A (en) | Cross-well electromagnetic well logging signal emission electronic system | |
| CN107356888A (en) | A kind of time difference type fluxgate sensor and time difference read method | |
| CN204945396U (en) | A kind of with the multifunctional wall body detection instrument apart from display and level meter | |
| CN107543973A (en) | A kind of rectangular pulse signal parameter measurement instrument | |
| CN100439904C (en) | Intelligent metal detector | |
| CN204832544U (en) | A metal sensor for location | |
| CN105510985A (en) | Mobile phone detection gate signal processing system | |
| CN104063674B (en) | Field strength adaptive circuit, field strength adaptive approach and smart card | |
| CN204331051U (en) | Digitally underground pipeline detecting instrument | |
| CN207215885U (en) | A kind of closed-loop current sensors | |
| CN207946538U (en) | A kind of metal detector | |
| CN105388348B (en) | A kind of enhanced autobalance bridge and its method for realizing open-loop compensation | |
| CN103955322A (en) | Lower-power-consumption capacitive touch screen control chip based on distributed type structure |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20091202 Termination date: 20160326 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |