JPS6357734B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in an audio frequency signal generator for monitoring material properties as disclosed in Japanese Patent Application Laid-Open No. 49-86088 filed by the applicant on July 10, 1972. Regarding.

Although it is well known that many attempts have been made to assess soil condition using soil conductivity measurements, these methods are unreliable for indicating soil moisture; Moreover, the measurement work is difficult, and the measurement results are of little value for the purpose of growing plants. Even if pure water with no impurities is produced, there is no electrical conductivity. Therefore, mere resistance measurement is meaningless when measuring the amount of water or impurities unless other impurities, such as fertilizer in the soil, are taken into account.

For the above reasons, FIG. 2 of the above-mentioned Japanese Patent Application Laid-open No. 49-86088, and FIGS. 3, 4, and 5 of the same application shown for various soils with and without fertilizer. The circuitry and apparatus that provide the audible signal information based on the type of data displayed on the graph are illustrated, and provide a simple and relatively easy-to-understand analysis of soil fracture moisture based on some of the relatively complex considerations discussed above. This allows accurate monitoring.

In view of the above, we provide a means for generating an audible signal that provides information about the resistance and capacitance between sensing probes inserted into a volume of material, these two parametric variables important for growth in soil. It is important to be able to monitor it easily.

It is therefore an object of the invention to provide a means comprising an audio frequency that is a function of the resistance of the conductive path through the sample and a modulation characteristic (pitch) that is a function of the capacitance of the conductive path through the sample between a pair of probes. It is about providing.

Another object of the present invention is to provide an oscillation circuit that measures and displays the resistance between a pair of probes in which a power source is connected between one of the probes and a speaker.

Still another object of the present invention is to provide a pair of probes having a total exposed area of both tips equal to or less than the square of the distance between the two probes, and an audible signal generating circuit connected between the two probes. The purpose is to provide a pair of probes.

Still another object of the present invention is to provide a method for measuring the impurity content in water and at the same time displaying both the resistivity and capacitance of a circuit passing through the impurity water as an audible signal.

Still another object of the invention is to provide audible signal information representative of resistance and capacitance between a pair of probes inserted into the soil so that relative measurements of both soil moisture content and fertility can be made using the audible signal information. The purpose is to provide a means that can be easily obtained from.

Another object of the invention is to provide circuit means including a pair of transistors for indicating the resistivity between a pair of probes and providing an audio frequency signal that increases to a cutoff frequency as the resistivity decreases. There is a particular thing.

Still another object of the invention is to provide an audible signal generating circuit means for indicating the resistance between a pair of probes, the frequency (cycles per second) being an integer that decreases in value as the resistance increases above about 1000 ohms. It is about providing.

Other objects of the invention will become apparent from reading the following specification and referring to the accompanying drawings, in which like reference numerals indicate corresponding parts in each figure.

Now, if we look at the circuits of FIG. 1 and FIG. 2, there are some similarities between the two circuits. That is, both circuits use a pair of transistors 211 and 215 in a relaxation oscillation type audio frequency oscillation circuit. This means that while the circuit shown in FIG. 2 of JP-A-49-86088 uses a single unijunction transistor and includes a power supply and switching means, the circuit shown in FIGS. Since the implemented circuit shown in FIG. 2 does not include switching means, excessive battery depletion, such as would occur if the switching means of FIG. No. The circuits of FIGS. 1 and 2 of this application use a general-purpose high-gain transistor, NPN transistor 215, and a general-purpose PNP transistor 211, along with other circuit elements having the values shown in the circuit diagrams. Operate. The resistor 213 in the circuit of FIG. 1 limits the current in the base 408 of the transistor 211 so that the capacitor 203 is inserted in series with the 15V voltage source applied between the terminals 205 and 207 of the probe. 34 and 3
Biasing transistor 211 prevents it from oscillating until it is charged through the conductive path between it and 6. When capacitor 203 is charged, PNP transistor 211 operates (conducting emitter 406 and collector 407) to operate NPN transistor 215, which causes a pulsed current to flow from emitter 403 through speaker input terminal 402 and through speaker 201. flows.

The pulse frequency (heard as a click sound) of the relaxation oscillator circuits in Figures 1 and 2 is
03 and exposed probe tips 111 and 114
The frequency-determining portion of this circuit, including the conductive path through the material between the

The main difference between the circuits of FIG. 1 and FIG. 2 is that resistor 213 (e.g., 4 kOhm) in FIG. The resistor 300 in the circuit shown in Figure 2 is inserted into the direct connection circuit from the base 408 to the emitter 406, and acts as a divider of the current between the base 408 and emitter 406, biasing the PNP transistor 211 according to its internal characteristics. , there is no need to connect this resistor to the probe 34 as in the circuit of FIG.

The dimensions of probes 34 and 36 are important; the total area A of both exposed tips 111 and 114 must be less than or equal to the square of the distance d between the probes. That is, (at both probe tips)
Let the total area be Ad ² . The reason is that if the total area A is substantially large, the resistance path between the probe tips will not be the correct total resistance of several parallel resistance paths. The probes 34 and 36 are solid rods made of aluminum with a cylindrical cross section, and are provided with an electrically insulating part 116 around the rod except for the tip, which is substantially the only conical end of the rod, and this conical The insulation extending to the ends consists of epoxy coating or anodized aluminum. To give an example of a probe that satisfies the above conditions, the distance d is 12.5 m/m, the diameter of probes 34 and 36 is 4.85 m/m, and the exposed tip area is formed by a conical rod end with an angle of 45°. be done.

Looking at the circuit of FIG. 3 and the graph of FIG. 4 showing the audible pulse frequency output as number of clicks per second in response to the resistive path of the material between probes 34 and 36, the pulse audible frequency The circuit is based on the number of pulses (click sounds) per second and the equivalent resistance between both probes (from about 40 kilohms to about 1000 ohms).
It can be seen (from FIG. 4) that a substantially linear relationship is formed between In this circuit, the first end of the secondary winding 514 of the iron core pulse transformer 512 and the PNP transistor 507 (power transistor 9012HG
The value of the capacitor 501 connected between the base 508 of the pulse frequency range affects the upper and lower frequency limits of the pulse frequency range. capacitor 501
When the value of is 220mfd, the response characteristics of the circuit as shown in FIG. 4 are obtained.

The actual frequency that represents the resistance of the material, i.e. clicks per second, is here set for the soil, and the actual frequency that is useful for determining plant growth conditions is the difference between the base 508 and the reference voltage. It is set by the leader resistor 503 connected between the resistor 5
When the resistance value of 03 is 1.6 kilohms, the response shown in the graph of FIG. 4 is obtained. In this way, upper and lower frequency ranges are selected and frequency tuning is achieved. Unlike the circuits shown in Figures 1 and 2 of the present application and Figures 1 and 2 of the above-mentioned Japanese Patent Application Laid-Open No. 49-86088,
continues to increase for low resistances down to 1 kilohm, as shown at the top of the graph, and rises rapidly for even lower resistances (not shown). Therefore, the number of clicks per second, which can be easily counted, covers the entire resistance range important for soil analysis, in practice approximately
It can be easily seen that a resistance change of 40 kilohms occurs over a large resistance change range from about 1 kilohm to about 40 kilohms. Transformer 512 includes an 8 ohm secondary winding for matched coupling to 8 ohm speaker 521.

The above graph of FIG. 4 allows the relative conductivity to be read to the desired level. For example 5
~6 clicks/second is about 4 kilohms (e.g.
(approximately 5 to 2 kilohms), which means a satisfactory moisture content for some plants, and higher clicks per second that begin to indicate excessive moisture and are no longer hydrated. It means it's not necessary. The audible signal generation circuit shown in Figure 3 is a capacitance formed by the soil between both probes (third
(see the dotted line in the figure). A weak, low-pitched pulse (like a cat's purr) that you hear as a click indicates a large volume and a significant amount of fertilizer; a short, high-pitched click or screech-like sound , indicating a lack of fertilizer with small capacity, eg salt water.
Thus, as can be seen, the circuit of FIG. Provides audible signal information including (pitch).

Of course, the RC circuit formed between probes 34 and 36 (see dotted line representation in FIG. 3) forms part of the frequency and pulse determining circuitry of the audio signal generation circuit of FIG.

If the resistance path between both probes drops below 1 kilohm and is out of the useful range, the pulse repetition rate will be reduced to 6.
It begins to increase very rapidly beyond the clicks per second and becomes uncountable, exceeding the linear operating range shown in Figure 4, and as the resistance continues to decrease and approaches a short circuit, for example from about 100 ohms to 500 ohms. When the resistance value is below, the bias voltage to the base 508 of the transistor 507 changes and the third
The audible frequency of the oscillation circuit shown in the figure is cut off. When there is a normal open conduction path condition between probes 34 and 36, such as when the monitoring probe is not in use, transistor 507 has no current generated to provide the necessary bias.
Since no bias is applied to the conductive state, unnecessary leakage from the 15V battery power supply 511 does not occur.

Examples of embodiments of the present invention are as follows.

(1) an apparatus according to claim 1, wherein said insulated conductor has a cylindrical cross-section, including a range in which said frequency of audible pulses is substantially directly related to an increase in resistivity of the soil up to at least about 6 pulses/second; 2. A device according to claim 1, wherein said exposed tip comprises a substantially conical end of said conductor.

(3) The device according to claim 1, wherein the rod-shaped periphery of the insulated conductor is covered with an electrically insulating member, leaving an exposed tip portion thereof.

(4) A device according to claim 1, wherein said audible pulse modulation of said audible pulse comprises an audio frequency modulation in which frequency decreases with increasing capacity.

5. Apparatus according to claim 1, wherein said audible pulse modulation of said audible pulse comprises pulse width modulation in which the length of said audible pulse decreases with decreasing capacitance.

(6) a speaker having first and second input terminals;
first and second probes, a resistor having first and second resistance terminals, a first transistor having a first emitter, a first collector, and a first base electrode, a second emitter, a second collector, and a second base electrode. a second transistor having
a voltage source having first and second battery terminals;
and a second capacitor terminal, the first probe having a second capacitor terminal.
the first capacitor terminal is coupled to the first input terminal of the speaker, the second input terminal of the speaker is coupled to the second emitter electrode, and the second base electrode is coupled to the first input terminal of the speaker.
a collector electrode, the second collector electrode is coupled to the first base electrode, the first emitter electrode is coupled to the first probe, the first battery terminal is coupled to the first capacitor terminal; The second battery terminal is coupled to the second probe, and the first resistive terminal is coupled to the first base electrode, and the second resistive terminal is coupled to the first or second probe. Signal device.

(7) a speaker, comprising a combination of an audio frequency generating circuit coupled to the speaker for providing an audible output pulse, the audio frequency generating circuit determining the pulse frequency and pulse modulation including a conductive path between a pair of terminals; the pulse frequency and pulse modulation determining portion of the audio frequency generating circuit provides an audio pulse of increasing frequency in response to a decrease in resistivity between the pair of terminals; An audible signaling device that indicates resistance and capacitance between a pair of terminals so as to provide an audible pulse of increasing length in response to increasing capacitance.

(8) An audible signal device according to embodiment (7), wherein the increase in pulse frequency is substantially linear over a range of about 40 kilohms to 1 kilohm.

(9) A combination of a loudspeaker and an audio frequency generating circuit coupled to the loudspeaker to provide audible output information representative of soil characteristics, the audio frequency generating circuit coupled to a pair of probes and between the probes. An audible signal device for monitoring soil properties responsive to resistive and capacitive properties of a soil and providing audible output information representative of the resistive and capacitive properties of the soil.

(10) The apparatus according to embodiment (9), wherein the probe has exposed tips having a total area less than or equal to the square of the distance between the exposed tips.

(11) The apparatus according to embodiment (9), wherein the audible information comprises an audible signal pitch representing capacity.

(12) The apparatus of embodiment (11) wherein said audible signal pitch has a frequency that increases in response to a decrease in capacitance.

(13) inserting a pair of probes into a liquid-containing substance, measuring the resistance between the probes, measuring the capacitance between the probes, and providing an audible information signal representative of the resistance and the capacitance; A method for measuring and displaying the conductivity and impurity content of a liquid or liquid-containing substance, comprising indicating the conductivity and impurity content of the liquid or liquid-containing substance.

(14) Said implementation, wherein said providing an audible information signal comprises providing an audible information signal having a pitch that increases in frequency in response to a decrease in volume to indicate a decrease in fertilizer impurities in the hydrated soil. Method according to aspect (13).

(15) Insert a pair of probes into the soil, measure the resistance between the probes, measure the capacitance between the probes, and simultaneously generate electric signals representing the measured resistance and capacitance values to A method of indicating soil moisture and fertilizer content comprising providing signals representative of moisture and fertilizer content.

(16) Any of the preceding embodiments, wherein the simultaneous generation of electrical signals representative of the measured resistance and capacitance as defined above generates periodic audible pulses having a repetition rate that is a function of the measured resistance and a pitch that is a function of the measured capacitance. 15) Method.

(17) A transistor having first and second probes, a base, an emitter, and a collector electrode;
and a capacitor having a second capacitor terminal, a resistor having a first and second resistance terminal, a battery having a first and second battery terminal, a primary winding having a first and second primary winding terminal, and a first and second resistor terminal. a pulse transformer comprising a secondary winding having two secondary winding terminals, a speaker combination having first and second speaker input terminals, the first capacitor terminal being coupled to the first secondary winding terminal; a first secondary winding terminal, the first secondary winding terminal being coupled to the first speaker input terminal, and the second speaker input terminal and the second secondary winding terminal being coupled to the first battery terminal. and an audible signal generator responsive to a resistance and a capacitance between the second terminal.

(18) a transistor having a pair of probes, a collector, an emitter, and a base electrode; a transformer having a primary winding and a secondary winding; a voltage source coupled between the primary winding and a reference potential; and the base electrode. a capacitor coupled between and the secondary winding; a resistor coupled between the base electrode and a reference potential;
and an audible signal utilization means coupled between said secondary winding, said collector and emitter electrodes and said first winding being connected in series between said second probe and a reference potential, said base an audible signal device, an electrode coupled to the first probe;

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram including a probe structure of an apparatus according to an embodiment of the present invention that utilizes a pair of transistors and a resistive bias for the first transistor of the pair. FIG. 2 is a circuit diagram including a probe structure for another device according to another embodiment of the present invention that utilizes a pair of transistors and a self-bias for the first transistor of the pair. FIG. 3 is an audible signal generation circuit diagram that provides frequency and pulsed outputs indicative of the resistance and capacitance, respectively, in the material between the probes. FIG. 4 shows the pulse frequency (number of clicks/number of clicks) of the audible signal of the circuit of FIG.
FIG. 34,36... Progue, 201,321...
Speaker, 215...NPN transistor, 2
11,507...PNP type transistor, 203,
501...Capacitor, 213,300,503
……resistance.

Claims (1)

[Claims] 1. A pair of insulated conductor probes with exposed tips whose total surface area is less than or equal to the square of the distance between the two tips, a speaker, and a conductor between the pair of probes. a combination of an audio frequency generating circuit for providing an audible information pulse having a pulse frequency determining and audible pulse modulating circuitry including a passageway, the audio frequency generating circuit coupled to the speaker and between the pair of probes. providing a pulsed audible signal with a frequency that is a function of the resistivity of the soil, and further providing audible pulse modulated audible signal information of the audible pulses as a function of the capacitance of the soil between the pair of probes; An apparatus for generating audio frequency signals for material property monitoring, characterized in that relative measurements of both soil moisture content and fertility are made with said audio signal information representing the resistance and capacitance between the probes of the soil.