CN201548524U

CN201548524U - Hand-held nondestructive testing instrument for maturity of watermelon

Info

Publication number: CN201548524U
Application number: CN2009200661189U
Authority: CN
Inventors: 刘志壮; 计春龙; 陈蓉; 刘玉善; 王江; 张勇彪; 洪自德
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-09-25
Filing date: 2009-09-25
Publication date: 2010-08-11
Anticipated expiration: 2019-09-25

Abstract

The utility model relates to a hand-held nondestructive testing instrument for the maturity of a watermelon. The testing instrument consists of a sound wave generator, a pre-positioned signal conditioning module and a DSP signal processing and comparing circuit that are connected in an order of the arrows in the figure. When the sound wave generator knocks the watermelon, the watermelon can generate a signal, and then the signal is amplified and filtered by the pre-positioned signal conditioning module, so that the conditioned signal is transmitted to a DSP signal processing circuit (comprising an ADC); the DSP signal processing circuit can generate an output signal, and the output signal is compared with the standard signal in a comparison circuit and then transmitted back to the DSP signal processing circuit; the comparison result is analyzed and processed, and finally, the result (the maturity) is displayed by an LCD.

Description

Hand-held watermelon degree of ripeness nondestructive testing instrument

Technical field

The utility model relates to a kind of device of energy Non-Destructive Testing watermelon degree of ripeness, and especially a kind of hand-held watermelon degree of ripeness detector by improving the degree of ripeness that can detect various kind melons, can be applicable to large-scale agricultural production, department store, Academy of Agricultural Sciences etc.

Background technology

The discrimination method of watermelon degree of ripeness has a lot, and modal is to beat the melon body with hand, judge its degree of ripeness by listening, but this method depends on operator's experience fully.In order to use a kind of comparatively objective, easy method of testing, some researchs have been carried out both at home and abroad: as the unit weight method, by measuring its degree of ripeness of the watermelon volume and weight section of declaring, be to use the volume and weight that watermelon is measured in the watermelon draining respectively, the result who measures or indicate by pointer, perhaps, be not suitable for the field and use by tabling look-up to determine that the method operation is comparatively complicated; The resistance method is judged the degree of ripeness of watermelon by the resistivity of measuring watermelon, is a kind of detection method that diminishes; Electronic equipment change of voice method, this class methods example is more, basically all be the resonant frequency of measuring watermelon, generally all collect sound by microphone, after operations such as amplification, filtering, or, provide measurement result by Computer Processing, or, still need artificial judgment by pointer instrument or loudspeaker output.With regard to practicality, the former volume is excessive, the cost height, and the latter still has certain requirement to the operator.

Summary of the invention

The utility model provides a kind of hand-held watermelon degree of ripeness detector, and it is intended to produce a kind of simple, cheap, easy device easily.

The utility model adopts following technical scheme: can reduce this characteristic according to watermelon along with the increase of degree of ripeness in the natural frequency that the various stage produced, compare the degree of ripeness of determining watermelon by measuring watermelon free running frequency and standard frequency, manufacture and design detector, it is made up of sonic generator, acoustic receiver, signal amplification circuit, signal processing circuit, low-pass filter circuit, sample circuit, ADC conversion, DSP signal Processing, signal comparator circuit, external standard frequency and liquid crystal display, and the assembly order of connection is shown in Fig. 4 arrow; Sonic generator comprises that pull bar, light spring, smooth trajectory, firing button, rubber knock mallet, leather cup and groove and buckles; Acoustic receiver comprises fixedly leather cup, microphone, pugging; Signal conditioning circuit comprises that signal amplifies and low-pass filter circuit; Signal processing circuit comprises ADC conversion, dsp chip and signal comparator circuit; The mimic channel that signal conditioning circuit constitutes by corresponding amplifier; The AD conversion chip can be with ADC0809 or other AD converter; The signal generator strictness has been controlled some may influence the factor of experimental result: such as eliminating friction with smooth trajectory; The pickup groove of being close to watermelon and signal generator inside with leather cup is buckled and is controlled the distance of launching; Be also noted that the dynamics of launching, in order to avoid the excessive damage watermelon of elastic force; Signal receiver is provided with pugging, can be used for eliminating some neighbourhood noises; Keyboard, display, signal Processing can be controlled with dsp chip.

Simple in structure, low cost of manufacture, easy to carry that good effect of the present utility model is is easy to promote.

Description of drawings

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

Fig. 2 sonic generator figure of the present utility model

Fig. 3 is the acoustic receiver figure of sound wave of the present utility model

Fig. 4 is the block scheme of sound wave of the present utility model

Fig. 5 is amplification, the low-pass filter circuit figure of sound wave of the present utility model

Among the figure: 1 buckle for groove for leather cup, 6 for knocking hammer, 5 for firing button, 4 for spring, 3 for pull bar, 2,7 for trajectory, 8 for fixing leather cup, 9 for microphone, 10 be pugging.

Embodiment

Referring to accompanying drawing 1-5, a kind of hand-held watermelon degree of ripeness detector is to be connected in sequence by sonic generator, acoustic receiver, signal amplification circuit, low-pass filter circuit, sample circuit, ADC conversion, DSP signal Processing, signal comparator circuit, external standard frequency generation circuit and LCD.Its sonic generator (as shown in Figure 2) knocks mallet 4, leather cup 5 and groove by pull bar 1, spring 2, smooth trajectory 7, firing button 3, rubber and buckles 6 and form.Pulling at spring is anchored to groove to reach the firing button place it is fastened, then sonic generator is close to the watermelon surface, press firing button 3, retracting spring 2 makes it knock watermelon, sonic generator just produces sound wave, via acoustic receiver signal being delivered to amplifying circuit amplifies it, then giving low-pass filter circuit with it carries out filtering, take out signal by sample circuit, by ADC change-over circuit and dsp chip signal being handled the back compares with the standard frequency of sending here, return to dsp chip again by the signal after the comparison, by its correct result (degree of ripeness) of DSP control liquid crystal display.

When concrete enforcement detects, in the accompanying drawing 2 sonic generator is close to the watermelon surface, when sonic generator is in extended state, press firing button 3, retracting spring 2 makes it knock watermelon, produce sound wave, this sound wave is delivered to amplifying circuit U1A through microphone with signal, U1B, U1C and low-pass filter circuit U1D, behind the ADC change-over circuit, be connected to dsp chip, by dsp chip its signal is handled, signal and standard-frequency signal are compared, its result by dsp chip control liquid crystal display displays is again " underdone "; " ripe "; " overdone " or press the quality that grade shows watermelon.

Claims

1. hand-held watermelon degree of ripeness nondestructive testing instrument, form by sonic generator, acoustic receiver, signal Processing, DSP circuit, ADC change-over circuit, signal comparator circuit, external standard frequency circuit and liquid crystal display circuit, the assembly order of connection is among the figure shown in the arrow, it is characterized in that; Sonic generator knocks mallet (4) by pull bar (1), light spring (2), smooth trajectory (7), firing button (3), rubber and leather cup (5) is formed, and pull bar is provided with groove button (6); Acoustic receiver is by fixedly leather cup (8), microphone (9), pugging (10) are formed; Amplifying circuit, low-pass filter circuit, comparison amplifying circuit are the LM324 integrated operational amplifier or other similar amplifier constitutes; Signal conditioning circuit comprises that signal amplifies and low-pass filter circuit; Signal processing circuit has comprised ADC conversion, dsp chip and signal comparator circuit; The mimic channel that signal conditioning circuit constitutes by corresponding amplifier; The AD conversion chip is ADC0809 or other AD converter.

2. hand-held watermelon degree of ripeness nondestructive testing instrument according to claim 1 is characterized in that: display is LCDs or other devices that is used to show.

3. the formula watermelon degree of ripeness nondestructive testing instrument of holding according to claim 1 is characterized in that: sonic generator is crooked shape or handle shape or pistol-shaped shape; Groove button on the pull bar is square or triangle or trapezoidal.

4. hand-held watermelon degree of ripeness nondestructive testing instrument according to claim 1 is characterized in that microphone is that Electret condenser microphone or other similarly convert voice signal to the generator of electric signal.