CN202453327U

CN202453327U - Ultrasonic wall detector

Info

Publication number: CN202453327U
Application number: CN2012200390615U
Authority: CN
Inventors: 张思俊
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-02-07
Filing date: 2012-02-07
Publication date: 2012-09-26
Anticipated expiration: 2022-02-07

Abstract

The utility model relates to a wall detector, in particular to an ultrasonic wall detector which comprises an ultrasonic transmitting device and an ultrasonic receiving device. The ultrasonic transmitting device comprises a synchronous scanning circuit, an ultrasonic transmitting circuit and a transmitting probe. The ultrasonic receiving device comprises a receiving probe, a pre-amplification circuit, a band-pass filtering circuit, a post-amplification circuit, a microcontroller and an alarm. Feature values of ultrasonic waves transmitted via a wall are acquired and are compared with stored prescribed ultrasonic feature values, and the alarm gives an alarm when the acquired feature values of the ultrasonic waves exceed a range. The ultrasonic wall detector is in modular design, modules work independently, and distribution conditions of nonmetal and non-conductor materials in the wall can be detected quickly and conveniently.

Description

A kind of ultrasound wave body of wall detector

Technical field

The utility model relates to a kind of body of wall detector, especially a kind of ultrasound wave body of wall detector.

Background technology

At present, domestic known body of wall detector all is based on Maxwell's Theory of Electromagnetic Field and designs, and the electric current of alternation can produce the electromagnetic field of alternation around it, reaches through electromagnetic detection and detects metallic conduit within the walls, the purpose of alternating current wires.In view of the body of wall detector based on electromagnetic detection can give off a certain amount of electromagnetic wave towards periphery, the operator is caused certain radiation, do not meet relevant criterion.In addition, general body of wall detector can not well detect the distribution situation of nonmetal and non-conductive material within the walls, causes detection difficult, causes misjudgment easily.

Summary of the invention

The utility model technical matters to be solved is to the deficiency of above-mentioned background technology, and a kind of ultrasound wave body of wall detector is provided.

The utility model adopts following technical scheme for solving the problems of the technologies described above:

A kind of ultrasound wave body of wall detector comprises: ultrasonic transmission device, ultrasonic probe, ultrasonic receiver, wherein:

Said ultrasonic transmission device comprises: synchronous scanning circuit, ultrasonic transmit circuit, transmitting probe, and the input end of ultrasonic transmit circuit is connected with the output terminal of synchronous scanning circuit, and the output terminal of ultrasonic transmit circuit is connected with transmitting probe;

Said ultrasonic probe, ultrasonic receiver comprises: receiving transducer, pre-amplification circuit, bandwidth-limited circuit, back level amplifying circuit, microcontroller, alarm; Wherein, Said receiving transducer, pre-amplification circuit, bandwidth-limited circuit, back level amplifying circuit, analog to digital converter connect successively; The data output end of analog converter is connected with the data input pin of microcontroller, and the high level output terminal of microprocessor is connected with alarm.

In the said ultrasound wave body of wall detector, microprocessor is the AT89C51 chip.

In the said ultrasound wave body of wall detector, analog to digital converter is the AD7705 chip.

The utility model adopts technique scheme, has following beneficial effect: can detect distribution situation nonmetal within the walls, non-conductive material quickly and easily.Whole ultrasonic ripple detector adopts modular design, and each module is relatively independent, precision is high, and the antijamming capability of supersonic reflectoscope is strong, obviously is superior to traditional body of wall detection instrument.

Description of drawings

Fig. 1 is the module map of ultrasound wave body of wall detector.

Fig. 2 is the schematic diagram of synchronous scanning circuit.

Fig. 3 is the schematic diagram of ultrasonic transmit circuit.

Fig. 4 is the pre-amplifying module circuit theory diagrams that are made up of AD621.

Fig. 5 is four joints, eight rank band pass filter circuit schematic diagrams.

Fig. 6 is the circuit theory diagrams of the back level amplification module that is made up of AD9631.

Fig. 7 is the interface circuit schematic diagram by A/D conversion chip AD7705 and microprocessor AT89C51.

Fig. 8 is the pin distribution plan of microprocessor AT89C51.

Fig. 9 is LED alarm lamp circuit theory diagrams.

Label declaration among the figure: U1A ~ U1I is phase inverter, and R1 ~ R27 is resistance, and C1 ~ C13 is electric capacity, and D1 ~ D3 is diode, and Q1, Q2 are triode, and Q3 is a power switch pipe, and L1 is an inductance.

Embodiment

Be elaborated below in conjunction with the technical scheme of accompanying drawing to the utility model:

Ultrasound wave body of wall detector as shown in Figure 1 comprises ultrasonic transmission device, ultrasonic probe, ultrasonic receiver.

Ultrasonic transmission device comprises: synchronous scanning circuit, ultrasonic transmit circuit, transmitting probe, and the input end of ultrasonic transmit circuit is connected with the output terminal of synchronous scanning circuit, and the output terminal of ultrasonic transmit circuit is connected with transmitting probe.Synchronous scanning circuit produces synchronizing pulse; Synchronizing pulse triggers ultrasonic transmit circuit and produces a high electric field pulse; High electric field pulse excitation ultrasonic transducer (piezoelectric chip) sends ultrasound wave, and ultrasound wave is launched through transmitting probe, and ultrasound wave is propagated through being coupled into cavity to be measured.

Ultrasonic probe, ultrasonic receiver comprises receiving transducer, pre-amplification circuit, bandwidth-limited circuit, back level amplifying circuit, analog to digital converter, microcontroller, the alarm that connects successively.The ultrasound wave that the body of wall to be detected that receiving transducer will receive returns is converted into faint electric pulse; Faint electric pulse is amplified into bandwidth-limited circuit through pre-amplification circuit and carries out filtering, shaping (wavelet de-noising); Simulating signal after level amplifying circuit in back is handled bandpass filtering modules block is amplified and is obtained useful signal, uses when supplying data acquisition and processing (DAP).Analog to digital converter is a digital signal with the analog signal conversion of back level amplifying circuit output; The eigenwert of the reflected signal of the same frequency ultrasound wave that prestores in the eigenwert of the digital signal that microprocessor comparison analog to digital converter is carried and the storer in even body of wall (no body of wall defective);, the difference of eigenwert sends electric signal when going beyond the scope, alarm equipment alarm.

Synchronous scanning circuit is used for producing synchronizing pulse and adjustable delay trigger pulse, and its schematic diagram is shown in Fig. 2.This circuit is made up of the HEF40106BP hex inverter; The 1st grade constitutes multivibrator by capacitor C 1, resistance R 1, potentiometer R2 and phase inverter U1A; The 2nd grade of monostable circuit that constitutes the rising edge triggering by capacitor C 2, resistance R 3 and phase inverter U1B; The 3rd grade is a phase inverter U1C; The 4th grade constitutes the monostable circuit that negative edge triggers by capacitor C 3, resistance R 4 and phase inverter U1D, and the 5th grade constitutes the monostable circuit that negative edge triggers by capacitor C 4, potentiometer R5, resistance R 6 and phase inverter U1E.

Be illustrated in figure 3 as ultrasonic transmit circuit, the effect of radiating circuit is to produce a very short pulse voltage de-energisation ultrasonic sensor (transducer) of duration, makes ultrasonic sensor (transducer) emission ultrasound wave.The pulse of emission is narrow more, and the along track resolution of equipment is good more, and the PV of emission is big more, and the sensitivity of detecting is just high more.What this device adopted is a kind of new radiating circuit, and this circuit need not provide high direct supply, just can produce the ultrasonic probe trigger pulse up to several hectovolts, and circuit theory diagrams are as shown in Figure 3.Triode Q1 (8050) and triode Q2 (8550) constitute one drive circuit in the circuit.General middle power VMOS pipe has the gate capacitance of nanofarad range, and switching voltage is 7～10V, and the maximum rise time was tens nanoseconds.Like this when produce driving the gate pulse of VMOS pipe, the gate current up to several amperes sometimes, this has exceeded the driving force of TTL chip.For improving the switching characteristic that pulse amplitude need strengthen the VMOS pipe, two double pole triodes constitute power amplification circuit among Fig. 3, drive back level VMOS pipe Q3.Ultrasonic transmit circuit is on-off element with VMOS, adopts the pulsating wave energisation mode, leans on inductive energy storage to form trigger pulse, does not need High Voltage Power Supply, and its energy storage only inductive current when changing the road square is directly proportional.When trigger pulse during positive pulse, the grid of Q3 is a high level, Q3 is equivalent to a small resistor, inductance L 1 resistance series connection therewith, and constitute a loop together with voltage source is charged to inductance, inductive current rises and carries out energy storage.When trigger pulse during negative pulse, the grid of Q3 is a low level, Q3 turn-offs fast, L1, C5, R8 and R9 form the resonant circuit rapid discharge, form driving pulse.Diode D1, D2, D3 play the individual event switch.The effect of playing dividing potential drop of resistance R 7, so that the effect of R8 is to be used for the amplitude of regulating impulse size in the protection Q3 circuit, when increasing the resistance of R8, it is big that the amplitude of pulse can become.Utilize the software emulation analysis, obtain the optimum value (being marked in the circuit theory diagrams) of relevant components and parts, so that ultrasonic sensor (transducer) emission is most effective.

Be illustrated in figure 4 as the pre-amplifying module of ultrasonic signal receiving trap; Because the reflection of sound wave on different medium interface and the decay of scattering and same medium propagation all can causing acoustic energy; The acoustical signal that actual piezoelectric chip receives is very faint, and on-the-spot undesired signal possibly flooded actual acoustical signal.Therefore, require pre-amplification circuit not only bigger input impedance will be arranged, high common-mode rejection ratio, and also noise is low, and satisfy and detect frequency span.That the pre-amplification circuit of this device uses is instrument amplifier AD621.Because instrument amplifier is a kind of through optimization process; Custom-designed accurate differential voltage amplifier; So it has lot of advantages; High like common-mode rejection ratio, nonlinearity erron is little, the high and low noise of input impedance, low maladjustment voltage and offset voltage drift, and has differential input, variable gain output.From the characteristics of instrument amplifier, be fit to very much faint voltage signal is amplified.Resistance R 11, R10 play the effect of balance resistance, make the balance of voltage of two terminals of amplifier, thereby make the bias current of amplifier can not produce additional offset voltage.

Like Fig. 5 is the circuit theory diagrams of the bandpass filtering modules block of signal, and the signal that piezoelectric chip receives also comprises noise after AD621 amplifies, carry out Filtering Processing, to extract useful signal.Because the centre frequency of piezoelectric chip is 500kHz, so the wave filter of design should be the BPF. that centre frequency is 500kH.The Filter Design index has: centre frequency f0=500kHz, quality factor Q >=10, enlargement factor Av=1.In order to obtain better filter effect, adopt the method for cascade to realize high-order band-pass filters.Adopt look-up table design BPF., and design with software.Last filtering circuit is the high-order band-pass filters that the second-order bandpass filter by four joint same structures adopts the method for cascade to constitute.Operational amplifier used in the BPF. is selected LM149 for use, and its bandwidth is 4MHz, can satisfy the requirement of BPF..It is 1% resistance that circuit is selected precision for use, so that make things convenient for the debugging of side circuit.R12, R16, R20, R24 are that resistance is the resistance of 11.4k Ω; R13, R17, R21, R25 are that resistance is the resistance of 315 Ω; R14, R15, R18, R19, R22, R23, R26, R27 are that resistance is the resistance of 20k Ω; C6-C13 is that the appearance value is the electric capacity of 100pF, and phase inverter U1F-U1I is the LM149 chip.Resistance R 12, R13, R14, R15, capacitor C 6, C7, phase inverter U1F constitutes the first-order filtering circuit; Resistance R 16, R17, R18, R19, capacitor C 8, C9, phase inverter U1G constitutes second-order filter circuit; Resistance R 20, R21, R22, R23, capacitor C 10, C11, phase inverter U1H constitute three rank filtering circuits; Resistance R 24, R25, R26, R27, capacitor C 12, C13, phase inverter U1I constitutes the quadravalence filtering circuit.

Be illustrated in figure 6 as the circuit theory diagrams of back level amplification module, after the receiving circuit that the output signal of BPF. amplifies through the homophase of being made up of AD9631 is handled, just can obtain a useful signal, supply subsequent conditioning circuit to carry out sampling processing.

Be illustrated in figure 7 as the interface circuit schematic diagram of A/D conversion chip AD7705 and microprocessor AT89C51.AD7705 is new 16 the sigma-delta A/ D converters releasing of AD company, can be used for measuring low-frequency analog signal.This device has programmable-gain amplifier, can come the various tiny signals of direct survey sensor output through software programming.AD7705/ AD7706 has characteristics such as resolution height, dynamic range are wide, self calibration, thereby is very suitable for fields such as Industry Control, instrument measurement.Wherein, AD7705 has two fully differential input channels, and AD7706 then has three accurate difference input channels.The utility model is to adopt AD7705, because it mainly has the following advantages: 1. have 16 nothings and lose code; 2. nonlinearity is 0. 003 %; 3. gain programmable, its adjustable range is 1～128; 4. outputting data updating rate is able to programme; 5. can carry out self calibration and system calibration; 6. have 3-line serial interface; 7. adopt 3V or 5V WV, low in energy consumption.

The pin figure of AT89C51 is as shown in Figure 8; Directly link to each other to come with AD7705 with AT89C51 the ultrasonic sensor signal is carried out analog to digital conversion; In order to control resetting of AD7705 effectively with software; Specially link to each other RESET with the P1. 2 of AT89C51 among Fig. 7, can guarantee that like this AD7705 can reset reliably.When using, the INT1 DRDY receives AT89C51 can make AD7705 that single-chip microcomputer is produced and interrupt, to read up-to-date translation data.

LED alarm lamp circuit theory diagrams as shown in Figure 9.Utilize the AT89C51 SCM system to the eigenwert of the reflected signal of same frequency ultrasound wave in even body of wall (no body of wall defective) and actual reception to the signal characteristic value compare; When the difference of two kinds of eigenwerts exceeds certain limit; Single-chip microcomputer provides electric signal; Light alarm lamp, reach with this and detect the purpose of pipeline within the walls.

Claims

1. ultrasound wave body of wall detector is characterized in that comprising: ultrasonic transmission device, ultrasonic probe, ultrasonic receiver, wherein:

2. ultrasound wave body of wall detector according to claim 1 is characterized in that said microprocessor is the AT89C51 chip.

3. ultrasound wave body of wall detector according to claim 1 is characterized in that said analog to digital converter is the AD7705 chip.