JPH01500143A - Device for detecting objects hidden behind surfaces - Google Patents

Abstract

A device for detecting objects (126) behind a surface (125) comprises a row of capacitive sensor plates (116a-116i) and a corresponding row of display elements (120a-120i). As the device is moved over the surface (125) the capacitor plates (116a-116i) sense variation in the apparent dielectric constant caused by the presence of an object (126) behind the surface (125). The display elements (120a-120i) change their display accordingly and present a visual representation of the object (126) and of edges of the object (126).

Description

[Detailed description of the invention] name of invention Device The present invention relates to a device for detecting objects behind a surface.

Hidden metal objects behind surfaces can be detected using metal detectors. child The detector connects a transmitter coil and a receiver coil, The magnetic induction generated between the coils is measured based on the so-called balanced inductor principle. It is. Metal detectors used in this manner include U.S. Patent No. 2,451,596. No. (Feeler), No. 2゜547.407 (Nelson), No. 2,557,99 No. 4 (Ostlund), No. 2,772,394 (Bradley), No. 3,88 No. 2,374 (McDaniel) and No. 4,255,711 (Thompson) and and German Patent Publication No. 2,718,132 (Reiners). can be lost.

If the dielectric properties of the surfaces are not homogeneous, their conditions may be due to moisture, hidden voids or hidden It can also be investigated by detecting capacitance so that objects can be detected. Wear.

No. 2,718,620 (Ho), 2°885 , No. 633 (Tuck), No. 3.043,993 (Maltby), No. 3゜046 ．． No. 479 (De et al.), No. 3,230,519 (Metz et al.), No. 3゜493. No. 854 (Trubrik), No. 3,515,987 (Trubrik et al.), No. 3 ．． No. 694.742 (Parsinanis), No. 3,967.197 (Anderson) ) and No. 4,099,118 (Frankley) and British Patent Publication No. 1,9. No. 52,194 (Associated Electrical Industries) and Examples include those described in No. 1,403,720 (Kihonsu).

A compact device that allows surfaces to be investigated both capacitively and magnetically inductively. The manufacturing problem is that the two types of sensors interfere with each other.

The present invention provides a device for detecting objects behind a surface, comprising: The device allows the support to remain in close proximity to the surface and move laterally over the surface. The transmitter plate means a capacitor for stray magnetic fields. The dielectric constant of the surface caused by the presence of hidden objects in the receiver plate means (dielectric constant), making it possible to respond to changes in The transmitter coil and receiver coil of the magnetic detector means are stray magnetic field capacitors. The electrostatic screen means is located behind the plate of the screen means and the stray magnetic field ( Stray field) A plate of a capacitor means and a core of a metal detector means. It is connected to a stationary reference potential, and is connected to a stray magnetic field key. The plate of the capacitor means and the electrostatic screen means are electrically conductive and are made of metal. The area orthogonal to the magnetic field from the detector means forms a continuous conductive path and the metal Circulating current caused by the magnetic field by the detector means rrent) is small, stray field capacitor means plate and electrostatic screen The means are adapted not to interfere with the operation of the metal detector means.

Resistant non-metallic materials as an approach to shielding and plate structures One example is to use a fee.

Stray magnetic field capacitor means plate and electrostatic screen means from conductive ink metal detector by creating a large circulating current in the metal detector means It has a surface resistance that allows it to store and discharge static charge without responding to the magnetic field from the device. There is. Alternatively, the shield and plate can be made from metal or other conductive material. but the area surrounded by a continuous conductive path orthogonal to the magnetic field from the metal detector means. It is divided into strips to minimize the area.

The invention further provides an apparatus for detecting objects behind a surface. and maintains close proximity to the device so as to be able to move laterally over the surface. a support and a number of capacitor plates spaced apart along the support. Detects changes in permittivity of localized areas of the surface as changes in each plate means. circuit means for displaying, and spaced apart circuit means along the display means, each having a a plurality of display elements connected to the plate means, each element The appearance changes depending on the dielectric constant of the local area of the plate means, and the support moves laterally. When moving past an object, the display is displayed according to the relative position of the object and the plate means. The appearance of the ray element changes and the edges of the object are imaged onto the display element.

The present invention arranges a large number of capacitor sensor plates to form a surface such as a wall. A picture image of an object hidden behind is formed by a display, and the elements of the display are is connected to each plate and is determined by the local permittivity change of the adjacent surface. Change visual state. If the hidden object is larger than the span of the capacitor plate. If narrow and mostly centered, view both edges on the display. Can be done. Otherwise, after one end passes the display, the other end section passes.

The necessary electronic circuits are assembled into application-specific integrated circuits (ASICs) and microcomputer chips. It is particularly advantageous to arrange it so that it is divided between the top and bottom. ASIC stray magnetic field generates signals for capacitive and inductive metal detectors, and It is controlled by a controller that processes the received signal and provides a digitized output.

Preferably, the circuit comprises a capacitor track on a support connected to the signal generating means. receiver plate means for the capacitor; A multiplexer is connected one after the other to the signal receiving means, and the dielectric constant is localized. reception of a modified signal from the transmitter plate means when the It is possible to detect. Detect magnetic field more effectively behind surfaces such as walls Guard plate means can be connected to provide access. guard plate The means surrounds a number of capacitor receiver plate means and the plate hand. A stationary base serving to partially shield the stage from the transmitter plate means. Connected to quasi-potential. Stray magnetic field capacitors in other forms of capacitive detection Examples of the use of pacitors are U.S. Pat. , No. 493,854 (Trubrik) and No. 2.718.620 (Ho). It is listed. U.S. Pat. No. 3,811,087 (Ho).

The multiple electrodes are formed from a plurality of conductive strips on the circuit board, which parallel to the plate means of the transmitter perpendicular to at least one end thereof; Capacitor receiver plate means and transmitter - The plate means is printed with conductive ink onto the flexible support of the circuit board. It is convenient to Google.

The transmitter frequency of the stray field capacitor is preferably approximately 50 KHz; This is desirable due to its relative insensitivity to moisture in the dielectric. The optimum between the wavenumber and the lower frequencies that are desirable in terms of electrode availability. This was discovered as a suitable compromise.

At least some of the receiver plates of the capacitor are connected to a power line. a second detector channel selectively provided to pass the frequencies of Advantageously, the input to the channel means is provided through a multiplexer means, The detector means is responsive to the detected power line frequency and displays a corresponding area in the display. area is working.

According to a further preferred feature of the invention, the transmitter coil of the metal detector means and a receiver coil located adjacent one side of the support away from the predetermined surface. , the transmitter coil is actuated by the signal generating means and the receiver coil is actuated by the signal generating means. The signal is sent to the signal receiving means through filter means and amplifier means.

(Brief explanation of the drawing) Embodiments of the present invention will be described by way of example and with reference to the accompanying drawings.

FIG. 1 is an exploded view of the object detector of the present invention.

Figure 2 shows a capacitive sensor on a capacitive sensor board forming part of the detector in Figure 1. Relationship to a liquid crystal display showing the plate area and forming part of the detector FIG.

FIG. 3 is a circuit diagram of the detector.

Figure 4 is a block diagram of an application-specific integrated circuit chip that forms part of the circuit in Figure 3. be.

(Detailed description of preferred embodiments) In the drawings, the case has a molded base (101) with a flat underside, on which A battery compartment (102) is formed and can be closed with a door (103). ing. A flexible circuit board (104) carrying capacitive electrodes is connected to the main circuit board (104). 05) and is fitted into the recessed surface of the molded base (101).

The reverse folded rim (106) is 0 at the back side of the rim supporting the lower capacitive sensor. ．． A spacing of at least 5 wheels, preferably about 2 wheels, is formed, and this spacing is equal to It can also be maintained using other means. Rim (106) is at (106m) is coated with an ink with controlled conductivity to create an electrostatic screen. form a means; The dielectric metal detector (107) consists of a pair of gold plates on a plastic member. It is equipped with genus detector coils (130) (131) (Fig. 3) and has a flexible lead. (108) is connected to the substrate (105). The detector is in the toolbox. The device is designed to be compact enough to be placed inside the device, making it suitable for metal inspection. The detector device (107) is connected to the board (104) rather than two side by side with the board (104). ) It is important to be able to fit it on the back side. lcd display (109) is connected to the substrate (105) by a lead (111) and is elastic. Vibration is prevented by the body (tio>) and it is fitted on the back side of the window (112). The window (112) is protected by the sliding cover (113) of (114). Upper mold The side of (114) is placed in position (119) each time the user uses the thumb and other fingers. so that the detector can be grabbed at approximately the same position in a predetermined manner. are doing. This also allows a capacitive or direct connection to the user. Ru.

Figure 2 shows a state in which a capacitive plate is placed on the front or lower rim of the substrate (104). and the relationship with the display (109). The electrode on the substrate (104) is stray Used in magnetic field capacitors, transmitter plate (115) and 9 pieces A straight line of receiver plates (116m) to (116i) is a guard plate. (117). Guard play) (117) is a plate ( 116m) to (116i), transmitter plate and receiver It is interposed between the plate. Guard plate (117) is receiver play (116a) to (116i) and reduce the magnitude of the magnetic field that reaches the receiver plate. A circuit is reliably formed through the detected substance. And behind the wall (125) The stud (12B) or other object hidden in the area changes the dielectric constant locally. substantially affects the strength of the signal received at the receiver plate. Increase the depth.

On the display (109), each plate (116a) to (116i) is a rod-shaped device. Display segments (120m) to (120i) are connected, and each segment For example, 10 subsegments are formed into strips, and the corresponding depending on the strength of the signal received by each receiver plate (116m) to (116i). Therefore, the states can be changed one after another. Electrode scans along wall (125) and passes through the main stud (126), if the stud (126) exists, Transmitter Brake) (115) to the receiver plate closest to it The current flowing through (116e) to (116i) is increased. As a result, the display The states of the isegments (120e) to (120i) change accordingly.

Since the value of each segment changes as the detector is scanned along the wall, The user has approached the stud (126) and the electrode row (116m) to (116i) ) passes through the stud and its starting point.

In order to make the device suitably compact, the receiver plate (116 m) ~ It is desirable to make (116i) as small as possible, and in the example, the width is 7.5 m + m, length 50m+m.

If the plate size is further reduced, the received signal will become too weak, as described below. This causes inconvenience in handling the transmitter circuit and receiver circuit. Trance Mitsutah plate (115) is located at both ends of plates (116m) to (116i). form a span. The width is not important; for example, if it is 10 to 50 + e-, the Function 1: There is almost no effect on the transmitter brake (115) and receiver brake. The interval between rates (116a) to (116i) can have a large effect on performance. When the determined zero interval is within the range of 10 to 50 mm, there is no performance problem and the value of 15 brass The optimum value is 7.5m+s and 30-, the performance drops to about half. It turned out that. Guard plate (117) is receiver plate (116m) ~(116i) is a transmitter that takes a path across the surface of the substrate (104). It has the role of insulating from the magnetic field from the plate (115). This sets the offset Increase this to cause fluctuations in the received signal caused by changes in the dielectric constant of the surface.

However, it is difficult to measure in a test. It is preferable that the plate (11)) not be wide. Preferably, a width of 2 to 31 is usually sufficient.

The metal detector coils (130) (131) in the material (107) are attached to the plate (11). Being able to place it on the back side of 6a) to (116i) makes it a compact device. However, capacitive sensors and dielectric metal detectors have been It was difficult to combine them like this. Plates (116a) to (116i ), (115) and (117) cannot be made from continuous metal, so Otherwise, the transmitter coil (13G) will draw a large amount of current and the receiver will This changes the magnetic field of the coil (131) and removes the hidden gold behind the test surface. However, capacitive The plate must be sufficiently conductive to act as a sensor element. The plate must be welded onto a substrate of desired thickness. 200-2000 ohms per square, preferably square It should be made from a material that provides a resistance of about 1000 ohms per square. Group Laffite, such as Mattheylec R4000 ( Screens based on epoxy resin containing graphite particles Thick film inks of polymers that can be printed are satisfactory, while silver The containing inks are usually too conductive. Plates (115), (116a) to (1 16i) and (117) need to be isolated from the metal detector coil in the same way. , Therefore, the back side of the substrate (104) is coated with one or more sheets made of conductive ink. Printing is done on a plate. A plate of conductive ink is a sensor Forms an electrostatic screen behind the plate, and this screen plate is connected to a constant grounding point. is connected to the

A single electrostatic screen plate may be sufficient, but the effect of voltage drop may be To avoid this, several plates can be used to form a screen with a split structure. may be desirable.

In Figure 3, the circuit board (105) is connected to the transmitter coil (105) of the metal detector. 30) and receiver coil (131), transmitter tarp of capacitive sensor Root (115), receiver plates (i16a) to (116i) and gar is connected to the doped plate (117). Other peripheral devices include buzzers (1 32), mode selector switch (301) and display (109) are included. Ru. The board (ios) is powered by the battery through the on/off switch <135>. -(134). The main element of the board (105) is an application specific integrated circuit (AS). I CHC1, and the integrated circuit is a 4-bit microcomputer IC2. Connected. The microcomputer IC2 has a display (109) disk. Includes a spray controller, which includes binouts (27) to (29), It operates via (31) to (6Z) and leads (111). battery voltage is The voltage is sent from the ICI bin VHC to the microprocessor-IC2 input VCC. The microprocessor's bins DIO, RIO and Dll are Provides lock input, data line and data direction line between ICI and IC2 do. Microcomputer IC2 controls the operation of ASICICI, You can receive data sent from there. resonator X1 is the clock oscillator bin 03CI of the microcomputer IC2 and 03C2, the clock pulses are also connected from the clock oscillator to the IC. I's uC clock bin. Plates (116a) to (116i) are This becomes the input for bins RX21 to RX29 of IC1. Metal detector equipment and capacitive sensor (115), (116a) to (116i) and (117) The guard plate (117), as well as the electrostatic screen between is connected to the output bin ANGRND of the potential. ICI output bin ANG RND is used to connect an external decoupling capacitor between this bin and BATN. This is an internally generated analog ground. Transmitter Great (11 The pulse to 5) appears on the ICI bin TX2, and the voltage Connected to one side of the step-up transformer.

Note that capacitors C12 and C13 are connected to the other side of the transformer. bottle T The output voltage of X2 is limited to 3 volts due to the working voltage of ICI. this In order to give a stronger received signal to the plates (116a) to (116i), T1 increases the voltage to 20 volts. However, the current that can be used in bin TX2 It is difficult to increase the voltage any further due to the limitations of C12 and C13. In between, a tap is provided so that the user can make a connection (136). User contact The continuation part appears in the area (119> of the upper mold (114). It is used in the area (119). The user places his or her finger on the conductive area or the on/off switch. This will result in

Capacitive sensors typically detect insulators and electrically isolated conductors, but The grounded conductor is not detected; this conductor is connected to the receiver plate (116a). Rather than returning a stronger signal to ~(116i), It deflects the magnetic field from the tar plate (115). If the user uses part of the signal By connecting (13B) to the transmitter plate (115), this some responses of capacitive detectors from grounded conductors. is expected to send a message.

The transmitter coil (130) of the metal detector is the bin TXI of the circuit ICI. , a unit gain driver network of the bush pull type that acts as a current amplifier. operates through the network. Pulses from bin TXI are connected to capacitor C9 and diode Transistors biased by resistors R9, R10 via the leads D2, D3 – Sent to the base of TRI and TR2. The transistor is resistor all, R1 2, and the output passes through the capacitor 010 and the coil (130) between the resistors. sent to. The receiver coil (131) of the metal detector is the chip ICI bottle R. It is connected between XI and ANGRND via a resonator filter. resonator The filter consists of an inductor L1, a resistor R1 and a capacitor 01. Ru.

A block diagram of the custom chip ICI is shown in FIG. Chip ICI is a signal Generator and transmitter block (201), receiver circuit block (202), phase sensitive detector (PSD) and analog-to-digital converter (A D C) block (203), decoder block (204), power supply (205) , the buzzer activation block (206) and the test switch matrix (207). be divided. The functions of the main blocks will be explained below.

Using the 400KH2 clock signal sent from the microcomputer IC2 , the block (201) is the transmitter coil (130) of the metal detector, the capacity gender sensor transmitter plate (115) and buzzer driver (20) 6) and generates a drive signal for the detector and transducer block (210). 203). The input clock signal on line (211) is buffered ( 212) to the divider (213) to generate the following:

(a) Eight relative phases consisting of 0 degrees, 45 degrees, 90 degrees...315 degrees 50KHz square waveform, square waveform output is from control line PH3ELO to Controlled from the decoder (204) by the 3 and cut code of PH3EL2 is sent to one of the eight selectors (215) selected from among the phases. This allows one of the signals to be passed as the reference signal for line (210). ing.

(b) Filter that removes residual harmonics 8-point sine approximation waveform sent to the filter (216), sine filtered The waveform shows that the control line (219) from the decoder (204) is active. When the switch (218) is closed in the state, metal detection occurs through the buffer (220). applied to the transmitter coil (130) of the device. Similarly, the sine waveform is , the control line (222) from the decoder (204) is in the active state. When the switch (223) closes, the capacitive sensor passes through the buffer (221). the transmitter plate (115) of the sensor. In this way, The microcomputer IC2 selectively creates capacitive sensors and/or metal detectors. Normally, the control lines (219) and (222) are Both lines can be active, but not at the same time is not prohibited, but when switches (218) and (223) are switched. It may happen instantly.

(e) 1°56KHz via AND gate (224) and divider (214) A square waveform buzzer drive signal is sent to the buzzer driver (206). game (224) is the control line from the decoding logic circuit (204). (225) is in the enabled state when it is in the active state.

A 400KHz clock signal is also routed from the output of the buffer (212) to line (2). 29) and is sent to the PSD and ADC block (203).

The receiver block (202) performs processing in the PSD and ADC block <203>. Before processing, the signal from the receiver coil (131) and the receiver plate (11 6m) to (116i) and set the conditions. Receiver coil (1 31) is connected between pin RX11 and ANGRND and has an impedance of 50 It forms the input to the receiver-amplifier (230) of approximately 1 Megohm at KHz.

The received signal may have a voltage of approximately 200 millivolts RMS at 50 KHz, RX The input signal is a predominant 50KHz signal and a This signal contains a 50/60 Hz signal, which may also be present. The signal is sent to an amplifier (230), and the gain of the amplifier is determined by the microcomputer IC. It can be set by the control from 2. Output of amplifier (230) is sent to a switch (231), which switches to a decoding logic circuit (204). ) closes when the line (232) from ) becomes active.

Capacitive sensor receiver play) Signals from (116a) to (116i) are sent to the receiver block (202) via inputs RX21 to RX29.

By checking the current received by each line at 50KHz, the sensor passes It is possible to know the change in permittivity of an object on the hidden surface of a wall.

Each receiver plate (116a) to (116i) has a peak peak of approximately 1 nanometer. The flow between the transmitter plate (115) of the amplifier (nana + ap) The change in the current caused by the change in current is detected by one counter of the A'DC output counter (2) 1) of the block (203). It corresponds to changes in the mount. Plates (116m) to (116i) are power line can pick up noise signals from external sources such as lights, fluorescent tubes, etc. I can do it. However, the noise is effectively removed by the filter (245) and P In the SD and ADC block (203), the response is approximately 50KHz and collected in the narrow band of the odd harmonies Ru. The noise in this band is considered to be significantly smaller than 1 nanoampere under normal conditions. available. The measured capacitance may range from 3 to 40 femtofarads, for example. The value is within the range. In the second mode, the transmitter coil (130) and the Both sensor plates (IIS) are in a disabled state and measurements cannot be made. 50/60 H2 component of the force current, and the signal has a peak peak of 15 na. Generates an AC current at a frequency of 0 amps. Lines Rx21 to RX29 are deco The programming logic circuit (204) is controlled by four select lines (234). It leads into a trolled analog multiplexer (233). line One line is selected from nine possible input lines depending on the state of (234). be done. Depending on the specific input and selector signal on line (234), the sensor signal is connected to one of the two inputs or to analog ground.

The first output from the multiplexer (233) is responsive to a 50KHz signal. It is sent to a current-voltage converter (235), and the resulting voltage is further amplified in (236). and sent to the switch (23)). Switch (237) is decoding logic When the control line (238) from the circuit (204) is active Since it is closed, only one of lines (232) and (238) will be active. . The gain of the amplifier (236) is determined by the digital code from the microcomputer IC2. It can be set by the code. Input RX2 from multiplexer (233) 4, the second output to Rx25, Rx26 is a second output responsive to a 50/60Hz signal. to a current-to-voltage converter (140). The output is a band pass filter (24 1), the filter passes the 50/60 Hz signal. Fi The output of the router (241) is sent to a peak detector (242), which has 50 /60 Measure the amplitude of the Hz element. Peak detector is decoding logic circuit When line (243) from (204) is active, each measurement cycle Cleared at start, the DC output on line (244) is PSD and AD It is sent to C block (203). Outputs of switches (231) (237) are metal The signal from the detector coil (131) or alternatively the multiplexer (233) ) selected by the particular receiver plate (116a)-(116i) carrier frequency (centre frequency) Connected to a 50KHz bandpass filter (245). Filter (2 The output of 45) is amplified in a dual gain stage (246). this gay During the decoding stage, the gain is applied to the line (247) from the decoding logic (204). ) is adjusted according to the state. Received signal output is PSD through line (248) and sent to the ADC block (203).

The PSD and ADC block (203) receives the battery voltage signal on line (250). and receives the received signal from the metal detector or capacitive detector on line (248). , receives the power line amplitude signal on line (244). These signals are decoded selected from among the lines (154) to (256) coming out of the logic circuit (204). When one of the two is in the active state, the respective Sent. The outputs of the three switches are sent to the PSD switch (157), which The switch is a control logic circuit that receives a 400 KHz clock on line (229). It is controlled by a line (158) emanating from a path (159). switch The output of (157) goes through the resistor (258) to the inverting input of the operational amplifier (259). Sent. A capacitor (280) is connected to the operational amplifier and the integrator , and the non-inverting input of the amplifier (259) is grounded. switch (157) When closed, the capacitor (260) stores electricity through the resistor (258). Kya The pacitor (260) is connected to the line (262) from the control logic circuit (159). When is in the active state, the switch (261) is pressed to discharge the battery. theory When the line (263) coming from the logic circuit (159) is in the active state, the switch (264) closes and connects the voltage generator (265) with the input resistor (258). Connect to width gauge (259). The voltage from the generator (265) is used as a reference signal. Sent. The output from the integrator (259) (260) is the comparator (2 70), and the output of the comparator at (269) is sent to the control logic circuit. This is the input to the path (159). The control signal is a 10-bit counter (2 71), and depending on its state it becomes an input to the latch (272), and its state is connected to the microphone via the data line (273) and the decoding logic circuit (204). It can be accessed by the black computer ICI.

between the decoding logic circuit (204) and the control logic circuit (159). When line (275) changes from inactive to active state, line (275) changes from inactive to active state. A conversion cycle synchronized with zio) begins. Once the conversion cycle begins, the Control logic circuit (159) over range, under range, conversion star the conversion complete and ramp-up complete latches are cleared; The counter (271) is reset to zero. Close the switch (261) and turn on. Preset the integrator capacitor (260) with a known voltage. line( 275) inactive and then active. The control logic (159) responds to the active edge of the signal and initiates a new conversion. The cycle can be started at any time.

After the conversion cycle has started, the underrange signal is output on line (276). Interference from microcomputer IC2, except when receiving cycle stops. Switches (252) and (157) are closed, proceeding without receiving , the voltage on line (248) passes through resistor (258) to capacitor (260). to store electricity. This is a constant number of cycles of the 400KHz clock on line (229). Electricity is stored for a cycle, and this cycle is counted by a counter (271). capa Once the voltage ramp-up at the lower (260) is complete, the control logic The circuit <159) clears the counter (271) and opens the switch (157) , close the switch (264). This allows the integrator (259) ( 260) is ramped down again (ramp-do@n), and the logic circuit (159) latches the status line (280) to the active state and lights the Instructs the logic circuit (204) that the upload has been completed. microcomputer reads the state of the latch control line (280) and indicates that the line is active. Input signal selection can be changed when in this state. The counter (271) While the cycle is in the ramp-down phase, by a pulse on line (229) clocked and the voltage on the capacitor (260) is the threshold of the comparator (270). (threshold) When it falls below VeoIIp, the logic circuit (159) Stop by. The value of the counter (271) is the load in the latch (272). and the status line (281) is set to the active state. By this Then, the microcomputer IC2 decides that it can read the data. rhinoceros When the system is in the ramp-up phase, the integrator (259) (260 ) depends on the voltage value of the input line (248). rhinoceros When the phase of the circuit is in ramp down, the voltage on the capacitor (280) is Up to the threshold value Vcomp of the comparator (270) at a controlled discharge rate The time to fall will depend on the voltage on line (248). Latch (27 The digital value loaded into 2) becomes the measured value of that voltage. Switch (253) The operation of input lines (244) and (250) passing through (251) is similar. this As such, depending on the value of the latch (272), the battery voltage, the transistor of the metal detector 50KHz between Sumitzer coil (130) and receiver coil (131) t-flow, capacitive sensor transmitter plate (115) and receiver plate 50KHzg flow between ports (116a) to (116i) or adjacent electrical wiring 5 induced into the plates (116d) to (116f) by the power line voltage of 0/60Hz @ current can be measured. The control logic circuit (159) , the input signal on line (244), (248) or (250) is at maximum full scale. If the range input is exceeded, the overrange latch is set and at the end of the conversion cycle. Set line (282) to active state. Input voltage of line (248) is insufficient, the underrange control that controls the state of line (276) The latch is set active and the ramp-up phase of the cycle ends. Then, the voltage of the indicators (259) and (260) is set to the threshold of the comparator (270). The input signal on line (248) and the reference signal on line (210) Indicates that the cycle will stop when the unit is removed from the finnies. microcomputer IC2 responds to the active state of line (276) and Line P) The phase of the reference signal from the selector (215) via ISEL2. Reset and correct the input signal on line (248) and the reference signal on line (210). The PSD switch (157) switches to the incoming signal on line (248). Time corrected for consistency. By startup, microcomputer The firmware of the IC2 is set by the outputs PH8ELO to PH3EL2. Test each possible phase and choose the one that gives the strongest signal. Fe A matched filter is used for the detector and the dual slope A/D converter. Form. Maximum ramp-up and ramp-down times are both approximately 2°5-1 seconds. , and the maximum time between successive start conversion signals is approximately 5-seconds. nine plates (116a) to (116i) are all preformed within a cycle time of 100a+m seconds. 5O-60Hz input condition through gates (116d) to (116f), metal detector and battery status can be detected.

The decoding logic circuit (204) is connected to the microcomputer IC2 and the custom circuit. The DATA line provides a continuous data link between the The DCLK line is used to synchronize data movement. The READ line is used to send the clock signal and control the data direction. sent to.

It will be clear that the device described above can perform three main functions:

(1) Plasterboard, chipboard, main panels, and walls and partitions inside buildings. A convenient tool for locating non-homogeneous objects (e.g. studs, needles, pipes, etc.) on the back side. Functional object detector.

(2) Metal detectors for locating metal objects behind non-metallic surfaces.

(3) Tracking live cables.

These functions can be performed in two modes of operation. default mode When the card is in operation (switched on), it can be used as a universal object detector. In this case, the output of the object detector is displayed continuously. This feature is displayed A signal is emitted by the indicator zone (306) of (109) (Figure 2). It will be done. When the battery voltage on line (250) is below the threshold, the battery An indicator (305) is activated to warn that Lee is in that condition. this When metal is detected in the mode, the microprocessor-IC2 Notify the user by flashing the light (300) and displaying it on the display. Ru. The user then turns on the switch (201) (display (109)) as necessary. The signal is illuminated by the indicator (307)) to switch to the second mode. It can be replaced.

The second mode is metal display and power line tracing mode, which is the metal detector output. The power is proportional to the strength of the received signal. Display as bar chart output (109) will be displayed. By switching to this second mode, the filter function is activated and the non- Metal objects do not affect the display (109).

In the second mode, the metal detectors (130) and (131) are activated, and in addition, the electrodes (1 The power line tracing functions of 16d) to (116f) are performed by the multiplexer (233). Operate. It will be displayed if a power line is present, but this also applies if metal is detected. It is done alone. The product has a voltage greater than 10V RMS and a frequency of 40 The presence of a working cable connected to an AC power line within the range of You should be able to give instructions. Works within electrical shielding forms such as metal conduit. Cables that are in a dynamic state cannot be detected; when the product is in use, the cables are exposed to current. Although it does not need to be flowing, it is in an operating state, that is, a state in which current flows when the switch is turned on. (I1ve), the presence of a power line means that the display segment (302) is displayed by flashing, and the buzzer (132) is activated by the driver. (206).

A typical detector configured as described above would require 20 pieces of plasterboard. The back side is the back side of 10mm plaster board + 51 plaster or 20mm You can check the location of the wooden squares on the back side of the chipboard.

Also, 10m plasterboard + 10mm space or 10wheels plus turbo card + 5th wheel theory plask + 5th theory space or on the back side of the 20m + * chipboard A steel pipe with a diameter of 14-1 can be found. Metal detector is 0.50mm I was able to find a 2゜5-2 power line cable, with a diameter of 14 in 0-120 theory. - It should be possible to find one copper tube, and the center position of the object at the maximum depth. is within the range of ±10−. The existence of the power line cable is a 10mm plus turbo + 5-wheeled plaster or 5- plaster or 5- plaster + 10m 2゜5III carrying 240V RMS behind the plow mortar conduit It can be detected in the cable of I2 or one wheel axle 2.

The three sensor groups operate independently and any interaction as far as the user is concerned is It will be understood that this does not occur.

The foregoing embodiments may be used without departing from the scope of the invention as defined in the appended claims. It will be understood that various modifications may be made to the embodiments.

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Claims (10)

[Claims] (1) A device for detecting objects on the back side of a surface, in which the support is close to the surface. The capacitor of stray magnetic fields is - means include transmitter plate means and receiver plate means, and the stray Capacitor means of the magnetic field is caused by the presence of objects hidden behind the surface. The metal detector means is capable of responding to changes in dielectric constant using a stray magnetic field capacitor. The transmitter coil and receiver coil are located on the back side of the plate of the transmitter means. and the transmitter plate means and receiver plate means are electrically connected. of an object behind a surface characterized by being made of a material that is resistant to air. Detection device. (2) between the plate of the stray magnetic field capacitor means and the coil of the metal detector means; is provided with an electrostatic screen means, which screen means is connected to a stationary reference potential. and the plate or each plate of the electrostatic screen means is electrically resistive. The stray field capacitor means are made from a material and spaced apart on the surface of the support. Includes a large number of capacitor receiver plate means, and an electrostatic screen. 2. Apparatus as claimed in claim 1, in which the connecting means is on the other side of the support. (3) The plate of the stray magnetic field capacitor means and the plate of the electrostatic screen means are Made from resistive ink, the magnetic field from the metal detector means induces large circulating currents surface that can store and discharge static charge without responding to the magnetic field. 3. A device according to claim 2, comprising a resistor. (4) Each receiver plate means surface caused by the presence of hidden objects. along with a circuit for detecting changes in permittivity in local areas and display means. It has multiple display elements spaced apart so that each display The elements are connected to the plate means, and each element has a local dielectric constant of the connected plate means. The display changes appearance as the support moves past the object. The appearance of these elements changes depending on the relative position of the plate means to the object, and Claim 3, wherein the edge portion is displayed as an image on the display element. equipment. (5) A guard plate means is provided, and the guard plate means includes a plurality of receiver plates. The transmitter plate is connected to a stationary reference potential surrounding the rate means. The plate means may be partially shielded from the receiver plate means. The device according to item 1 of the scope of demand. (6) The transmitter plate means is connected to the signal generating means and the receiver plate means is connected to the signal generating means. The plates of the rate means are passed one after the other to the signal receiving means by multiplexer means. Transmitter plate means connected and caused by local changes in dielectric constant According to claim 3, it is possible to detect the reception of a modified signal from equipment. (7) The receiver plate means is formed by a plurality of resistive pieces, and the resistive pieces are adjacent a transmitter plate means orthogonal to at least one end of the resistor strip; The dimensions of each receiver plate are is 107.5mm x 50mm, transmitter plate and receiver plate The distance between the transmitter and the electrostatic screen is 7.5 to 30 mm. - A plane approximately 2 mm away from the plane on which the plate means and receiver plate means are located. The resistant ink contains graphite particles in a resin or binder. , the resistance of the plate means and the resistance of the screen means are about 200-20 per square 4. The device according to claim 3, wherein the device is 0.00 ohms. (8) The detector means is provided with a 50° - Indicates the presence of a live electrical cable in response to a 60Hz current and capacitor The magnitude of the signal received by the receiver plate means of the receiver is indicated on the display means. and the magnitude of the signal from the metal detector means is determined by the display means. Contains control means switchable between the second mode shown above. Apparatus according to claim 1. (9) A device for detecting an object behind a surface, which is close to the surface. a support that can be moved over the surface while maintaining the shape of the support; Due to the presence of a large number of capacitive coupe plates placed in open spaces and the presence of hidden objects, a circuit for detecting a change in dielectric constant occurring in a localized region of the surface of each plate means; , a plurality of spaced display elements along the display means. Each display element has a plate means and each element has a plate means. The appearance changes depending on the dielectric constant of the local area of the support, and the support moves to pass the object. If the display elements are too large, they will respond to the relative position of the plate means with respect to the object. The appearance changes as the edges of the object are imaged onto the display element. A device for detecting objects behind the surface. (10) The circuit includes a transmitter provided on the support and connected to the signal generating means. one after another to the signal receiving means by the filter means and the multiplexer means. including receiver plate means to be connected, and when the dielectric constant changes locally Allows detection of reception of altered signals from transmitter plate means 9. The apparatus according to claim 9.