CN109220738B - Soil humidity monitoring device cultivated in a pot - Google Patents

Abstract

The invention discloses a potting soil humidity monitoring device which mainly comprises a humidity sensing electrode carbon rod, a control box and a peristaltic pump; the control box takes an STC15 series single chip microcomputer or a single chip microcomputer ESP-12 with WIFI as internal processing control, and also comprises a soil humidity detection circuit, a peristaltic pump driving circuit, a liquid crystal display screen, a lower key and an upper key; the two humidity sensing electrode carbon rods are connected with the control box; the control box displays the current soil humidity through the liquid crystal display screen; a plurality of IO ports of the single chip microcomputer are connected with the liquid crystal display screen, the lower key and the upper key, one IO port of the single chip microcomputer outputs square waves to be connected with the input end of the soil humidity detection circuit, and the ADC input port of the single chip microcomputer is connected with the output end of the soil humidity detection circuit; a plurality of output ports of the singlechip are also connected with a plurality of peristaltic pump driving circuits; the invention has the advantages of fully playing the function of the single chip microcomputer, and particularly has the advantages that the single chip microcomputer with the WIFI function can realize remote monitoring and the like.

Description

Soil humidity monitoring device cultivated in a pot

Technical Field

The invention relates to the field of planting equipment, automatic control and WIFI internet of things, in particular to a potting soil humidity monitoring device.

Background

The automatic watering control device for the flowerpot is commonly found in a temporarily built measurement and control system or a timing and quantitative watering device, and the special field mainly uses agricultural irrigation equipment. Portable and simple-to-use household small and exquisite soil humidity monitoring equipment is rarely seen. Although recently, the soil humidity detection insert with the chip on the printed circuit board is also designed, the soil humidity detection insert is easy to corrode by soil, has a plurality of connecting lines and high cost, and is not suitable for a great amount of applications in the small-pot close planting type future family interesting planting of snack boxes or milk tea cups.

Disclosure of Invention

This application has just built one set of simple to operate's domestic flowerpot automatic watering controlling means with modern singlechip, especially take WIFI's singlechip, display screen, and succinct antipollution be convenient for quantitative peristaltic pump just right to design control box as general as far as possible, include the earth humidity control operation method based on "two keys on a screen", and WIFI cell-phone computer remote monitoring.

The technical scheme adopted by the invention for solving the technical problem is as follows: a device for monitoring the humidity of potting soil mainly comprises a humidity sensing electrode carbon rod, a control box and a peristaltic pump; the control box takes an STC15 series single chip microcomputer or a single chip microcomputer ESP-12 with WIFI as internal processing control, and also comprises a soil humidity detection circuit, a peristaltic pump driving circuit, a liquid crystal display screen, a lower key and an upper key;

two humidity sensing electrode carbon rods are vertically buried at two sides of the flowerpot separately and are connected with the control box through two humidity sensing electrode connecting wires and a humidity sensing electrode connecting plug; the peristaltic pump water is led to the flowerpot through a peristaltic pump water pipe, and a power supply wire plug of the peristaltic pump is connected with the control box; the control box is powered by 220V power supply inlet wire plug connection; the control box displays the current soil humidity through the liquid crystal display screen, when the soil dryness reaches an upper threshold value, the intermittent automatic watering is started, and after the soil humidity detection for less than half an hour, the automatic watering is stopped to enable the soil humidity to be stabilized at a lower threshold value; that is, the upper and lower thresholds are defined as: end points of a suitable dry-wet range for planting soil;

in the control box, a plurality of IO ports of the single chip microcomputer are connected with the liquid crystal display screen, the lower key and the upper key, one IO port of the single chip microcomputer outputs square waves to be connected with the input end of the soil humidity detection circuit, and the ADC input port of the single chip microcomputer is connected with the output end of the soil humidity detection circuit; a plurality of output ports of the singlechip are also connected with a plurality of peristaltic pump driving circuits;

the key-down and key-up operation method comprises the following steps:

the upper key has the following operation functions: pressing for a long time, namely pressing for more than 1 second, adding water, and stopping adding water when releasing; short pressing, namely pressing for no more than half a second, displaying an upper threshold, and after 2 seconds, restoring the current humidity display by numerical display; when entering an upper and lower threshold setting mode, an upper threshold setting mode indicator or a lower threshold setting mode indicator appears, at the moment, the short press is numerical value increase, the long press is threshold value storage, and the threshold setting mode exits, the threshold setting mode indicator disappears, and the numerical value display resumes the current humidity display;

the lower keys have the following operating functions: short pressing, namely pressing for no more than half a second, displaying a lower threshold, and after 2 seconds, restoring the current humidity display by numerical display; when entering an upper threshold setting mode and a lower threshold setting mode, reducing the short-time pressing value as a numerical value; long pressing, namely pressing for more than 1 second, entering an upper threshold setting mode, then entering a lower threshold setting mode, sequentially alternating, and displaying an upper threshold or a lower threshold with a corresponding upper threshold setting mode indicator or a corresponding lower threshold setting mode indicator; automatically quitting in a threshold setting mode without operation for 10 seconds;

lower threshold setting 0 indicates turning off watering, lower threshold setting 1 indicates watering is always on;

the soil humidity detection circuit comprises a triode Tr, a diode D, a resistor R0, a resistor R1, a resistor R2, a resistor R3, a capacitor C and a capacitor C1; the PWM square wave signal output by the singlechip is connected with a resistor R3, the other end of the resistor R3 is connected with the base electrode of a triode Tr, the collector electrode of the triode Tr is connected with a resistor R1, the other end of the resistor R1 is connected with +12V, meanwhile, the collector electrode of the triode Tr is also connected with a protective resistor R0, and the other end of the resistor R0 is respectively connected with one end of a blocking capacitor C and the positive electrode of a peak value rectifier diode D and is marked as a point T; the other end of the blocking capacitor C is connected with one pole of a humidity sensing electrode carbon rod, the other pole of the humidity sensing electrode carbon rod, the Tr emitter, one end of the filter capacitor C1 and one end of the load resistor R2 are all grounded, the negative end of the peak rectifier diode D, the other end of the load resistor R2 and the other end of the filter capacitor C1 are connected together to serve as the output end of the soil humidity detection circuit, and the output end is connected with the input end of the single chip microcomputer ADC;

or, the soil humidity detection circuit comprises a time-base circuit NE555, a diode D5, a resistor R4, a resistor R5, a resistor R0, a resistor R1, a resistor R2, a resistor R3, a capacitor C5, a capacitor C and a capacitor C1; the 2 and 6 feet of NE555, one end of capacitor C5, resistor R4 and one end of resistor R5 are connected together, the other end of resistor R5 is connected with the anode of diode D5, the cathode of diode D5, the other end of resistor R4 and the 3 feet of NE555 are connected together, the 8 foot of NE555 is connected with one end of resistor R1 to +12V, the other end of resistor R1, one end of resistor R0 and the 7 feet of NE555 are connected together, the other end of resistor R0 is respectively connected with one end of DC blocking capacitor C and the anode of rectifier diode D to be recorded as point T, the other end of DC blocking capacitor C is connected with one pole of humidity sensing electrode carbon rod, the other end of capacitor C5, the 1 foot of NE555, one end of filter capacitor C1 and one end of negative terminal resistor R2 are all connected to ground, the negative terminal of peak value rectifier diode D, one end of resistor R2, one end of filter capacitor C1 are connected together to be used as the earth output terminal, the output end is connected with the input end of the singlechip ADC;

the humidity sensing electrode carbon rod is characterized in that one end of the carbon rod is tightly wrapped with a circle of conductive metal ring, a humidity sensing electrode connecting line is pressed or welded through the conductive metal ring, and resin is coated or plastic package is carried out on the conductive metal ring;

or the humidity sensing electrode carbon rod is formed by electroplating a layer of metal on one end of the carbon rod, welding a humidity sensing electrode connecting wire on the metal coating, and coating plastic or potting resin on the metal coating and the root of the welding wire;

the peristaltic pump driving circuit comprises an NPN triode T8, a P-type MOS tube pMos, a diode D8, a capacitor C8, a resistor R8, a resistor R81 and a resistor R82; one output port of the single chip microcomputer is connected with a resistor R8, the other end of the resistor R8 is connected with a base electrode of an NPN triode T8, a collector electrode of an NPN triode T8 is connected with one end of a resistor R82, the other end of the resistor R82 and one end of a resistor R81 are connected with a grid electrode of a P-type MOS tube pMos, the other end of the resistor R81 and a source electrode of the P-type MOS tube pMos are connected together to +12V strong current, a drain electrode of the P-type MOS tube pMos is respectively connected with one end of a pump power supply line plug, the negative end of a diode D8 and one end of a capacitor C8, and the other end of the pump power supply line plug, the positive;

or the peristaltic pump driving circuit comprises an N-type Mos tube, a diode D8, a capacitor C8 and a resistor R8; one output port of the single chip microcomputer is connected with a resistor R8, the other end of the resistor R8 is connected with a gate of the Mos tube, a source electrode of the Mos tube is grounded, a drain electrode of the Mos tube is respectively connected with one end of a pump power supply line plug, the positive end of a diode D8 and one end of a capacitor C8, and the other end of the pump power supply line plug, the negative end of the diode D8 and the other end of the capacitor C8 are connected together to be connected with +12V strong current;

when the control box takes a single chip microcomputer ESP-12 with WIFI as internal processing control, the single chip microcomputer ESP-12 with WIFI is connected with a mobile phone or a computer through a wireless network, the single chip microcomputer ESP-12 with WIFI is matched with LUA script language programming firmware of a NODEMCU, a selected program module comprises WIFI, NET, an MQTT protocol, a GPIO port and an SPI port for operation, and the remote Internet of things adopts the MQTT protocol;

when the control box is connected with the mobile phone or the computer, the display interface of the mobile phone or the computer is listed line by line in a list form: the current humidity, the upper threshold value and the lower threshold value correspond to one path in each row; clicking an upper threshold or a lower threshold to directly input numerical value modification at any time;

the mobile phone or the computer is connected with the control box through the WIFI and is divided into three networking modes:

in the mode 1, the single-chip microcomputer ESP-12 with WIFI in the control box is a WIFI AP webpage server, and a mobile phone or a computer is connected with the WIFI and is accessed to 192.168.4.1 by a browser; the mode can monitor humidity, and is mainly used for setting a singlechip ESP-12 with WIFI in a control box, so that the singlechip ESP-12 can be connected with a wireless router or available WIFI, including WIFI names and passwords, and displaying connected (DHCP) IP for the connection of the following mode 2; in the method, the external network of the mobile phone or the computer is not connected, so that the mobile phone or the computer is only used for setting a WIFI name and a password at the beginning of networking;

mode 2, a singlechip ESP-12 with WIFI in the control box is automatically connected with a wireless router or available WIFI, the WIFI name and password are set in advance by the mode 1, and a (DHCP) IP displayed after connection is recorded; the mobile phone or the computer is also connected with the wireless router or the available WIFI, and the control box can be connected at any time to monitor the humidity only by using the browser to access the recorded IP; in addition, a networking indicator light is added, and a control box mode 2WIFI connection is indicated to be successful;

the mode 3 is that the control box comprises an Internet of things MQTT protocol, and the mobile phone or the computer is remotely connected with the control box through the MQTT protocol to monitor the humidity;

furthermore, the 12V working voltage of the soil humidity detection circuit is changed into 5V by some varieties, so that the resistance Rl can be reduced by times, and the soil humidity detection circuit is suitable for detecting humidity-resistant planting; under the condition, the output of the switching power supply is 12V and 5V, and the 5V outputs 3.3V through the LDO type three-terminal regulator to supply working voltage to a singlechip or an ESP-12;

or a diode D in the soil humidity detection circuit of some varieties is connected with a voltage stabilizing tube in series, so that the output voltage of the soil humidity detection circuit is reduced by the voltage stabilizing value of the voltage stabilizing tube, and the saturated value of the soil humidity is close to 0;

or the upper end of the resistor R2 is connected with a voltage stabilizing tube in series, and the humidity detection voltage is output from the connection point of the voltage stabilizing tube and the resistor R2, namely the connection point of the voltage stabilizing tube and the resistor R2 is connected with the input end of the single chip ADC, so that the output voltage of the soil humidity detection circuit is reduced by the voltage stabilizing value of the voltage stabilizing tube, and the soil humidity saturation value is close to 0;

the voltage stabilizing tube is a Schottky diode with forward voltage drop of 0.3V, a common silicon diode with forward voltage drop of 0.6V or a patch voltage stabilizing tube with forward voltage drop of 2.2V and 3.3V.

Furthermore, some varieties combine the humidity sensing electrode connection plug and the peristaltic pump power supply line plug into a three-pole plug;

for 4-path monitoring, 4 tripolar jacks are arranged, the liquid crystal display screen has four numerical displays, and each numerical display corresponds to one path of humidity value; the selection key is connected with an IO port of the single chip microcomputer, the selection key is switched to be pressed at any time, and all the ways are alternated; the soil humidity detection circuit also comprises a one-out-of-four integrated circuit CD 4052; a common end (A)13 pin, (A0)12 pin, (A1)14 pin, (A2)15 pin and (A3)11 pin are connected with 4 paths of blocking capacitors C and one electrode of a humidity sensing electrode carbon rod respectively from a T point, two selection pins (S0)10 pin and (S1)9 pin are connected with two ports of a single chip microcomputer, and one path of the 4 paths is controlled and selected; 4 output ports of the singlechip are connected with 4 paths of peristaltic pump driving circuits.

Furthermore, a quasi-resonant soft switching power supply is adopted for 220V voltage transformation of the control box; the 12V power supply has a current limit protection function.

Furthermore, the control box also comprises a beep buzzer and an LED indicator lamp which are connected with the IO port of the single chip microcomputer, the LED indicator lamp is normally on when the control box works normally, the LED indicator lamp flickers when abnormal conditions occur, and the beep buzzer sounds.

Furthermore, a connector is added at the connection position of the two humidity sensing electrode connecting lines and the humidity sensing electrode connecting line plug.

Furthermore, the control box further comprises a main power switch which is connected in series with the inlet wire of the power inlet wire jack.

Furthermore, the control box can also include integrated circuit 74HC595, and the output pin of 74HC595 connects liquid crystal display, and the singlechip passes through the serial input pin of SPI interface connection 74HC 595.

The invention has the beneficial effects that: the 'one-screen two-key' control box for controlling the soil humidity and related components are designed, and the control box comprises a high alternating voltage reading circuit for measuring the soil resistance through alternating current excitation and a single chip with WIFI (wireless fidelity) selected to enable the control box to be capable of connecting a mobile phone or a computer through WIFI (wireless fidelity) so that the operation is more visual and the network remote monitoring can be realized, thereby forming a whole set of practical and general device in a proper manner.

The flowerpot does not need a bottom hole, is water-tight and is more sanitary.

Because of the small and exquisite low price of the carbon rod electrode, no matter pre-buried before planting, long-term insertion after planting or repeated insertion, the planting management and maintenance or small pot dense planting of the damaged roots are not influenced, all potted plants can be inserted with the carbon rod electrode, and a set of device is used by a plurality of pot wheels.

The device has adjustable adaptability to dry planting and moisture-proof planting, and is a rare economic and applicable device for strictly controlling soil humidity for germination and seedling planting key links afraid of moisture and dryness.

The upper and lower threshold values which can be displayed at any time are the end point marker post values of the dry and wet application range of the planting soil.

The WIFI networking system formed by the ESP-12 has the characteristic of high cost performance (one set is less than 50 yuan), the remote monitoring adopts an MQTT Internet of things lightweight protocol, even in a non-network site, cheap 4G wireless small-flow packets (less than 100 yuan per 1G in packet year) can be used, and the typical requirement of (remote) monitoring of soil humidity of potted plants is met.

Drawings

FIG. 1 is a schematic view of a device for monitoring humidity of potting soil according to the present invention;

FIG. 2 is a circuit diagram of soil moisture detection;

FIG. 3 is a circuit diagram of a time-division switching 4-way detection circuit;

FIG. 4 is a view showing an appearance of the multiplex control box;

FIG. 5 is a circuit diagram of a peristaltic pump drive;

FIG. 6 is a circuit diagram of another peristaltic pump drive;

FIG. 7 is a circuit diagram of soil moisture detection formed by the 555 time base circuit;

in the figure, 1, a liquid crystal display screen, 2, an upper threshold setting mode indicator, 3, a lower threshold setting mode indicator, 4, a lower key, 5, an upper key, 6, a humidity sensing electrode connecting plug, 7, a humidity sensing electrode connecting wire, 8, a peristaltic pump power supply wire plug, 9, a peristaltic pump, 10, a peristaltic pump watering pipe, 11, a peristaltic pump water inlet pipe, 12, a water storage tank, 13, a power supply wire inlet plug, 14, flowerpot soil, 15, various selection keys, 16, a three-pole jack, 20, a humidity sensing electrode carbon rod.

Detailed Description

The convenient and simple automatic watering all the device components are set up as shown in figure 1, wherein the control box is the core and is used for pump power supply adaptation and key humidity control. The simple and visual automatic pouring cement soil humidity control based on humidity and upper and lower threshold setting is realized by only using one display screen with two keys.

An overview of automatic watering control based on humidity and upper and lower threshold settings is: two humidity sensing electrode carbon rods 20 are vertically buried at two sides of the flowerpot soil 14 separately (the planting body is in the central range of the two, so that the humidity detection is comprehensively balanced), and are connected with the control box through two humidity sensing electrode connecting wires 7 and a humidity sensing electrode connecting plug 6 (which can be very long). The control box is by liquid crystal display 1 demonstration current earth humidity, starts intermittent automatic watering when the earth dryness reaches the upper threshold value, through the earth humidity detection of less than 1 hour, stops automatic watering and makes earth humidity stabilize at lower threshold value (otherwise the error alarm, for example lack of water, water pipe block up etc.).

Note that the key here is "soil moisture detection after less than half an hour, stopping intermittent automatic watering to stabilize soil moisture at the lower threshold": the watering is not simply stopped at the lower threshold value, the soil seepage situation is variable, the soil is accumulated and is not dispersed, and the watering is stopped when the soil is watered, namely the watering is stopped when the soil is watered simply to the lower threshold value. Therefore, the 'intermittent automatic watering' is not continuous watering, but gradual detection of watering stop and stopping is carried out according to the historical watering quantity and the water seepage reflecting time, the acceleration or the slowing of water seepage is particularly monitored in the period, and the watering time is shortened on the premise of controllable watering until the soil humidity is stabilized at the lower threshold (if the soil humidity is not stabilized, an error is reported). The lower threshold value thus defined (for user operation) is of course simple and trouble-free.

The algorithm for optimizing automatic watering is not discussed, nor is it claimed (the basic method is simply to add a little water in series, compare the lower threshold after they stabilize), but only to emphasize that: the upper and lower thresholds thus defined are actually the end-bar values of the suitable range of dry and wet planting soil (but there are differences in the sense electrode burying changes).

The specific operation method matched with the control box comprises the following steps:

the up button 5 is used for numeric addition, displaying an up threshold and manually adding water:

the water is added by long pressing (not holding for more than 1 second), namely the peristaltic pump is electrified to water, and the water is stopped when the peristaltic pump is released. Short according to, press promptly and do not exceed half a second promptly, show the threshold value, liquid crystal display 1 shows current earth humidity by at ordinary times and becomes to show the threshold value, and 2 seconds later numerical value display resumes current humidity and shows. If the upper and lower threshold setting mode is entered (an upper threshold setting mode indicator 2 or a lower threshold setting mode indicator 3 appears), the short time is increased according to the value; and long pressing is to store the current display value as a new threshold (namely, setting the new threshold, otherwise, the original threshold is not changed), the threshold setting mode exits, the indicator of the threshold setting mode disappears, and the display screen resumes the current humidity display.

The lower key 4 is used for digit reduction, lower threshold display and upper and lower threshold setting:

and (4) short pressing, namely pressing for no more than half a second, displaying a lower threshold, and after 2 seconds, restoring the current humidity display by numerical display. If the up-down threshold setting mode has been entered (with an up or down threshold setting mode indicator present), the short press is decremented. The long press (press and hold for more than 1 second) enters an upper threshold setting mode, and the long press (after release) enters a lower threshold setting mode, and the steps are sequentially alternated. After entering the upper and lower threshold setting mode, the corresponding upper threshold setting mode indicator 2 or lower threshold setting mode indicator 3 appears, and the liquid crystal display screen 1 displays the upper or lower threshold, and the 10-second no-operation threshold setting mode automatically exits (the original threshold is not changed).

The automatic control is that water is added manually (the key 5 is pressed for a long time) before satisfaction, the humidity display value is observed, and the water adding is started when the value is determined (dried) repeatedly and is used as the upper threshold value of the dryness. When the water is properly added by repeatedly observing for many times, the humidity display value is continuously reduced, and the lower threshold value of the humidity is used when the humidity display value is small (the soil absorbs water uniformly and stably, and the humidity display value can be up to half an hour for different planted soils).

The upper and lower thresholds are set at will (the upper threshold is not set to be entered by mistake, for example, the upper threshold is set to be smaller than the lower threshold), and the setting can be adjusted at any time, and the improvement is gradually reached.

The watering pipeline is specifically led to the flowerpot by a peristaltic pump 9 or a submersible pump (without watering first) through a watering pipe 10 of the peristaltic pump. The peristaltic pump has small flow and large lift, the watering liquid flows in only one pipe, the peristaltic pump does not contact with mechanical parts of the pollution pump, the peristaltic pump 9 or the submersible pump pumps water into the water storage tank 12 through the peristaltic pump water inlet pipe 11, no special requirement is required for the water storage tank 12, the peristaltic pump is placed at a high position and a low position, and the device is very suitable for planting and watering potted plants.

The control box uses a singlechip STC15 series or a singlechip ESP-12 with WIFI as internal processing control, a plurality of IO ports of the singlechip drive the liquid crystal display screen 1, an upper key 5 and a lower key 4, an IO port of the singlechip outputs a PWM square wave to be connected with the input end of the soil humidity detection circuit (square wave) shown in figure 2, and an ADC input port of the singlechip is connected with the output end of the soil humidity detection circuit shown in figure 2. Four output ports of the singlechip control a four-way peristaltic pump driving circuit (control the operation/stop of the pump).

The circuit diagram (including one circuit) of each peristaltic pump is shown in FIG. 5. A series resistor R8 at the output port of a single chip microcomputer is connected with an NPN transistor T8 base electrode b, a T8 emitter electrode e is grounded, a T8 collector electrode c series resistor R82 is connected with a P-type low-resistance MOS tube pMos grid electrode g, the pMos tube grid electrode g is also connected with a resistor R81 to +12V (strong current), the source electrode s of the pMos tube is connected with +12V (strong current), the drain electrode d of the pMos tube is connected with one end of a power supply line plug 8 of a peristaltic pump 9, and weak isolation switch type driving (the motor is short-circuited or a switch tube is burnt out and cannot damage the single chip microcomputer) between different power supplies (the power supply of the single chip microcomputer is 3V) with. In the actual circuit, the two ends of a power supply line plug 8 of the peristaltic pump are also connected in parallel with a back electromotive force anti-interference absorption circuit consisting of a reverse diode D8 and a capacitor C8.

The low-on-resistance power MOS tube which is newly appeared in recent years is applied, the low-on-resistance is dozens of milliohms (below), no radiating fin is needed for pump current of about 1A, the installation structure is simplified, the volume is extremely small (patch), and the low-on-resistance power MOS tube is particularly suitable for multi-way switch driving (which is the key of small volume). In addition, the MOS tube grid current is zero, and power supply (strong current) of power of more than 12V is realized, so that the problem of large drive power consumption (unmatched control voltage of the base electrode of the transistor of 0.6V) caused by large base current by using the transistor as a switching tube is completely avoided.

If the power supply line plug 8 of the pump does not have to be grounded at one end (a four-pole plug is used when combined with the humidity sensing electrode connection plug 6 as a jack), the pump drive circuit is simplified to: an output port series resistor R8 of the singlechip is connected with a grid g of an N-type low-resistance MOS tube, a source s of the MOS tube is grounded, a drain d of the MOS tube is connected with one end of a pump power supply line plug 8, and the other end of the pump power supply line plug 8 is connected with +12V (strong current) as shown in figure 6.

Effective detection of soil humidity is a success or failure key of the system, and besides the basic requirements of stability and reliability of soil humidity detection, the system also needs to be anti-interference, multi-path switchable and convenient for numerical value adjustment.

The soil humidity detection circuit selects a high alternating voltage reading method for measuring soil resistance by alternating current excitation shown in FIG. 2, and comprises the functions of band elimination square wave source, multi-path switchable alternating current excitation output, weak peak value rectification and humidity working section indication value adjustment:

the PWM square wave (inherent function of the single chip microcomputer) output by the single chip microcomputer is connected with the input end of the soil humidity detection circuit shown in the figure 2, the input end is connected with a transistor Tr base electrode b through a resistor R3, a Tr collector electrode C is connected with a resistor R1 to +12V (high-voltage strong electricity), the Tr collector electrode C is connected to a point T through a protection resistor R0, namely the other end of the R0 is connected with a direct-blocking capacitor C and the anode of a peak rectifier diode D, a square wave output point T (starting from 0V and the height of the top of the square wave changes along with humidity and is suitable for CD4052 to conduct multi-path switching) with the bottom always being 0V is obtained, the other end of the C (serving as an alternating current excitation output end) is connected with one pole of a humidity sensing electrode carbon rod 20 (namely one pole in two humidity sensing electrode connecting wires 7.

The negative end of the peak value rectifying diode D is connected with a parallel circuit of a resistor R2 and a filter capacitor C1 to the ground, the negative end is a detection voltage output point of the soil humidity detection circuit and is connected with the input of a 0-3.3V singlechip ADC, and the input corresponds to the whole range of humidity display values.

The functional points of the elements are as follows:

two humidity sensing electrode carbon rods 20 are inserted into soil to form a resistor, and are connected to a square wave output point T through a blocking capacitor C to form a load, the more wet the soil is, the smaller the resistor is, the lower the square wave output voltage at the point T is, the bottom 0V of the square wave is ensured by conduction of Tr, and the top height of the square wave is pulled up by R1 when the top height is closed by the Tr. Therefore, R1 is the internal resistance of the alternating current excitation voltage, the larger R1 is, the more close to the constant current source, the more suitable the dryness of the dry sand is measured, namely the discrimination of the dry section is improved (except for desert plants, the more demanding is the germination and seedling growing which are afraid of being over wet), so the device is called as a 'square wave source with resistance'. D. The peak value rectifying circuit formed by C1 and R2 is used for reading a voltage value (a stable direct current voltage value) at the top height of a T-point square wave, but the peak value rectifying circuit has the defects that burr interference is feared, Tr is conducted at the bottom, the caused burr interference has no effect on the peak value rectifying circuit, and R2 is infinite to be an ideal peak value rectifying circuit, wherein the output voltage is adjusted by R2, so that the drying value (or an upper threshold value) of the measured soil falls on the high level of a display value, for example, one byte of computing capability suitable for a single chip microcomputer is generally adopted, one byte of 0-255 is used as a planting soil humidity indicating value range (for planting, 256 levels of humidity are enough for distinguishing), the soil is dry (can be used as the upper threshold value), but the indicating value is about 100, and then R2 is added to improve so as to improve the output voltage; or the soil is not dry, but the indication value is 255, the R2 is reduced, the output voltage is reduced, and the humidity working section indication value adjustment is called. Therefore, R2 is typically several tens of K (C1 is less than 0.47uF), and is not true "peak rectification" but is called "weak peak rectification" because it has a low-pass filtering effect (anti-interference). R0 is a protection resistor to prevent Tr from being burnt by discharge current of C when two humidity sensing electrode carbon rods are collided together due to conduction of Tr.

If 4-path detection is needed, a common end (A)13 pin, (A0)12 pin, (A1)14 pin, (A2)15 pin and (A3)11 pin of a four-select-one integrated circuit CD4052 are connected with a T point, respectively, one pole (see figure 3) of a humidity sensing electrode carbon rod (20) connected with 4 paths of blocking capacitors C in series is connected with the pins (A3), 10 pins of two select pins (S0) and 9 pins (S1) are connected with two ports of a single chip microcomputer, and one of the 4 paths is controlled and selectively connected. Thus, time-switched 4-way detection is achieved with only two single-chip ports and a cheap four-out-of-one universal integrated circuit CD4052 (four sets of humidity detection circuits plus ADC selection are not used). The universal one-out-of-four integrated circuit CD4052 can be used because the T-point square wave is non-negative (not directly applied to the humidity sensing electrode carbon rod 20 input, here the ac excitation output point, CD4052 cannot operate on ac).

Instead of outputting the PWM square wave signal (or saving the port) by the single chip, the time base circuit NE555 is used, as shown in fig. 7. Here, the 7-pin discharge tube in the time base circuit NE555 replaces the above-mentioned transistor Tr, and the astable circuit formed by NE555 replaces the single chip microcomputer to output the PWM square wave signal. The 3-pin output of the NE555 is connected with a resistor R4 to charge and discharge the C5, and is also connected with an R5 string D5 branch in parallel, so that the bottom on-time of the T-point square wave signal is adjusted to be smaller than the upper off-time, and the T-point square wave signal is more favorable for detection.

Some varieties will change the 12V working voltage of the soil humidity detection circuit to 5V, so that the resistance Rl can be reduced by times, and the detection of the moisture-proof planting is more suitable, namely, the resolution ratio when the soil is wet is increased, namely, the section of the digital display 40-100, and the drying section is naturally saturated to the maximum value of 255 earlier. In this case, the output of the switching power supply is 12V (power strong electricity) and 5V (soil humidity detection circuit), and the 5V outputs 3.3V through the LDO type three-terminal voltage regulator (such as HT7133 and AMS1117) to supply the working voltage of the singlechip or ESP-12.

If the water is required to be added to saturation (accumulated water can be seen from the transparent box), the reading is close to 0, and a voltage stabilizing tube can be connected in series with a diode D in the soil humidity detection circuit, so that the output voltage of the soil humidity detection circuit is reduced by the voltage stabilizing value of the voltage stabilizing tube; or the upper end of the resistor R2 is connected with a voltage stabilizing tube in series, and the humidity detection voltage is output from the connection point of the voltage stabilizing tube and the resistor R2, namely the connection point of the voltage stabilizing tube and the resistor R2 is connected with the input of the single chip ADC, so that the output voltage of the soil humidity detection circuit is reduced by the voltage stabilizing value of the voltage stabilizing tube. The former approach is theoretically very poor linear (and therefore generally not useful) near the 0 value, but has the function of extending the resolution of readings at earth moisture saturation.

It is shown that the resolution of the entire humidity detection range is improved substantially from 0, which is the wetest point.

The voltage-stabilizing tubes are Schottky diodes with forward voltage drop of 0.3V, ordinary silicon diodes with forward voltage drop of 0.6V (note that the voltage-stabilizing tubes below 1V are replaced by the forward junction voltage of the diodes), and patch voltage-stabilizing tubes of 2.2V and 3.3V. R2 or R1 can be adjusted slightly, but the effect of adjusting R2 or R1 on the high end of the dryness is large, so the low end is adjusted by a voltage stabilizing tube.

Supplementary points are described here:

not to use the simpler direct current wet soil resistance is to avoid the polarization phenomenon that the carbon rods in the wet soil can generate chemical cell effect, and the polarization potential of the carbon rods gradually rises after a long time, which leads to misjudgment that the soil is dry (even the electrode is considered to be separated);

firstly, the connection between the humidity sensing electrode carbon rod 20 and the humidity sensing electrode connection plug 6 can be more than three meters, only a common thin twin wire is needed, and one of the two twin wires is grounded and can be combined with a power supply line plug 8 of the pump to form a common three-pole plug (the two share one ground wire), so that the jacks are reduced; secondly, the input range of the single chip microcomputer ADC is adapted to 0-3.3V (an input amplification stage is not needed, one operational amplifier is saved, and related positive and negative power supply configuration and a filter circuit are also saved);

and an upper threshold and a lower threshold after being adjusted in place are end-point bar values of a suitable range of the dry soil and the wet soil, and only the current carbon rod of the humidity sensing electrode is buried. Different burying methods have different values, and different sizes and different soils have larger difference.

However, from the actual planting and actual measurement conditions, the stability, the consistency and the satisfaction are still satisfied, the most strict control of sun-shading-free summer solarization and watering is taken as an example, the sweet potato leaves and the malan heads (which are relatively moisture-proof) are observed by soft soil of common saprophytic mud (mixed with proper amount of soil), no matter a transparent snack box, a big round box packed with soup, a flowerpot water-receiving outer sleeve box or a milky tea cup is used as a planting pot, the transparent boxes with different shapes and sizes are deliberately selected to be more visual for observation, and have no water bottom holes, thereby saving water and being sanitary; humidity sensing electrode carbon-point length 4CM, diameter 0.4CM, all at soil surface straight cutting, two are apart from 10CM, and the plant is densely planted in the centre, and the observation result is all basically: when the indication is about 150, water must be added (the plants are dry and hang down); water was added to 50 a to begin saturation (water accumulation was visible from the transparent box). The soil is soft humus soil, water is added in the middle of a humidity sensing electrode carbon rod with the distance of 10CM, and the value is stable after a little water is added for 5 minutes. The value of the humidity sensing electrode carbon rod is almost unchanged after being pulled out.

The implant is in the middle range of the two humidity sensing electrode carbon rods, so that the humidity detection is comprehensively balanced (especially important for a drying section); the humidity sensing electrode carbon rod is not tightly attached to the edge of the flowerpot, and the soil is separated from the edge of the flowerpot in a whole circle when being dried and shrunk.

The operating voltage of the soil humidity detection circuit is set to be 12V, so that the soil humidity detection circuit is suitable for plants (belonging to the application of a drying section) which are afraid of excessively wet rotten roots, and the germination and seedling growing which are greatly required are extremely afraid of excessively wet.

The single chip microcomputer has the function of outputting the PWM square wave signal, and the duty ratio can be set. In fact different duty cycles may also perform some dirt classification functions.

In summary, as shown in the circuit for measuring the earth resistance by ac excitation in fig. 2, the used elements are few, simplified and in place, the adaptive surface is wide, and the adjustment is convenient (the functions of the elements are independent and definite).

The humidity sensing electrode carbon rod 20 has a structure that one end of the carbon rod is tightly wrapped with a circle of conductive metal ring, the metal ring is in compression joint with the humidity sensing electrode connecting wire 7, and resin or plastic package is coated outside the metal ring, so that the metal ring and a lead wire are isolated from chemical reaction or oxidation caused by the moist environment of soil. The carbon rod has good contact compatibility with the moist environment of the soil (reducing the contact resistance with the soil) and the carbon rod is never oxidized or corroded away. Because of the small size and the low price of the carbon rod electrode, the planting management and maintenance or the small pot dense planting of the wounded root are not influenced no matter whether the electrode is pre-buried before planting, inserted for a long time after planting or repeatedly inserted and pulled. The carbon rod electrodes are inserted into the potted plants, and at least one set of device can be used for multiple pot wheels.

A connector (comprising one to three, namely after being pulled apart, single wires of the two humidity sensing electrode connecting wires 7 are also separated) is added at the connecting part of the two humidity sensing electrode connecting wires 7 and the humidity sensing electrode connecting wire plug 6, so that the device is convenient to disassemble, move and carry or is a set of device for multiple basins and wheels.

The actual potted plant for growing flowers usually has more than one pot, and a plurality of pots need more sets, so that the pot is very inconvenient, and particularly, the power lines are more and unsafe. A scheme for controlling 4-way monitoring of the cartridges is also designed for this purpose, see fig. 4. The liquid crystal display screen 1 of the design has four numerical displays, and each numerical display corresponds to the humidity of the 1-way three-pole jack 16 (namely, the upper two are 1 way and 2 way, and the lower two are 3 way and 4 way); a respective path selection key 15 is further added to select which path the operation is directed to when the upper and lower thresholds are to be set, and the other three values are temporarily turned off or changed ___ (referred to as the current path display, or changed once the upper and lower threshold setting mode is entered, and then the four humidity value displays are restored upon exiting). When the selection key 15 is pressed at any time, the respective paths are rotated. However, when the current route is not displayed, the current route is displayed by pressing the selection key 15 for the first time (in order to prevent the problem that the current route is to be confirmed again after the current route is displayed for 2 seconds, and the next route is selected by pressing the selection key 15), and at this time, the next route is selected by pressing the selection key 15 again.

In order to reduce the connecting wires in multipath, the humidity sensing electrode connecting wire plug 6 and the peristaltic pump power supply wire plug 8 are combined into a common three-pole plug 16 (the two plugs share a ground wire), so that a power supply wire inlet plug 13 can be provided with four paths of automatic watering pumps (4 three-pole jacks 16).

The humidity sensing electrode connection 6 may be tied to the watering pipe 10.

Individual ones also include a mains power switch (push button).

In order to solve the problem of remotely monitoring soil humidity during traveling or business trip, the intelligent control box also comprises a WIFI internet of things function which can be monitored and operated by a mobile phone or a computer network, wherein a singlechip in the control box is an ESP-12 module with the WIFI function and is matched with LUA script language programming firmware of NODEMCU, and the intelligent control box already comprises program modules forming the internet of things, such as work calling functions of WIFI, NET, MQTT protocol, GPIO port operation, ADC, a temperature sensor DS18B20, I2C, RS and the like, so that programming development is greatly simplified, and the intelligent control box can be realized only by using LUA script language.

The mobile phone or the computer monitors the humidity through the network, and the operation is more convenient and visual, especially the multi-path. The display interface lists line by line in the form of a list: the current humidity, the upper threshold value and the lower threshold value correspond to one path in each row. Clicking the upper threshold or the lower threshold at any time (jumping out of an input box, directly inputting numerical values, including that the lower threshold is set to be 0 to indicate that watering is closed, and the lower threshold is set to be 1 to indicate that watering is opened all the time, and characters of ON, OFF, ON and OFF can be directly input) for modification.

The WIFI connection control box of the mobile phone or the computer is divided into three networking modes:

1. the control box (ESP-12) is a WIFI AP webpage server, and a mobile phone or a computer is connected with the WIFI and is accessed 192.168.4.1 through a browser. And an external network is not required to be accessed and a wireless router is arranged. Besides monitoring humidity, the method is mainly used for setting the control box (ESP-12 therein) so that the control box can be connected with a wireless router or available WIFI (wireless fidelity) comprising WIFI name and password, and displaying connected (DHCP) IP for connection of the following mode 2. The mobile phone or the computer is not connected with the external network, so that the mobile phone or the computer is only used for setting the WIFI name and the password at the beginning of networking.

2. The control box (ESP-12 as STATION) connects to the wireless router or the available WIFI by itself, sets the WIFI name and password in the manner of 1, and records the Displayed (DHCP) IP. The mobile phone or the computer is also connected with a wireless router or available WIFI (namely the original networking is unchanged), and the control box can be connected at any time to monitor the humidity only by accessing the recorded IP (such as 192.168.0.103) through a browser.

Note that, at the beginning, the control box can only be connected in the mode 1 because the WIFI name and password are not set, and after the WIFI name and password are set for the control box, the mobile phone or the computer can be connected in the modes 1 and 2. Especially, an LED networking indicator lamp can be added, and the control box (mode 2) is lighted to indicate that the WIFI connection is successful.

3. The control box comprises an Internet of things MQTT protocol (which is connected in a mode 2 and responds to the MQTT protocol), and a mobile phone or a computer can be remotely connected with the control box through the MQTT protocol (through an MQTT server) to monitor the humidity.

There are many free MQTT servers available on the network, such as livemq.com, cloudqtt.com, iot.

For monitoring by the computer, the program can be started by double clicking only by copying a paho. javascript plug-in (which communicates with MQTT through WEBSOCKET) and an HTML5+ JS operation interface program into the computer.

For mobile phone monitoring, a page.javascript plug-in and an HTML5+ JS operation interface program (mqtt _ JS/index.htm) are placed under sdcard/download/path, and opened with a chrome (HTML5 type) browser at the website file:///mnt/sdcard/download/mqtt _ JS/index.htm. These may also be placed on a web site that the browser would access conventionally. The method also avoids the situation that the APP is downloaded and installed by the mobile phone.

The starting current of a motor of the peristaltic pump is large, the motor protects a switching power supply and a pump driving switching tube, the pump +12V power supply comprises an overcurrent limiting current function, and besides the common operational amplifier for current detection, the motor can be more simply realized by using a DK401 special IC, see DK401. PDF.

A quasi-resonance soft switching power supply is adopted for 220V voltage transformation, and typical ICs and circuits refer to PDF documents such as NCP1207, NCP1377, NCP1380 and the like, so that a MOS high-voltage switching tube has a small heat dissipation plate (or does not need to generate heat, and the heat is equivalent to a rear Schottky rectifier tube, which is the key of small volume), and is particularly suitable for variable load operation of a multi-path peristaltic pump motor.

When water is short, the water pouring pipe 10 of the peristaltic pump is blocked or falls outside, the connecting wire 7 of the two humidity sensing electrodes is loosened or the connecting plug 6 of the humidity sensing electrodes is loosened, and the internal self-checking abnormity has a sound alarm and an LED indicator lamp flickers. The alarm is a beeper connected to the single chip. The LED indicator is usually a power-on indicator, but a liquid crystal display screen is usually not provided with a power-on indicator, and the upper threshold setting mode indicator 2 and the lower threshold setting mode indicator 3 can be used to flash at the same time instead of or in place of the flashing of a corresponding indicator. When the network is connected, an alarm (corresponding to a certain path) appears on the mobile phone or the computer.

The liquid crystal display screen is divided into two types, an icon customization type and a dot matrix type. The upper threshold setting mode indicator 2 and the lower threshold setting mode indicator 3 in the icon customized type may be small letters, open circles (solid circles indicate validity); the lattice type may be represented by appropriate characters.

For the economical single-chip microcomputer STC15F408AS or ESP-12, if a parallel liquid crystal display (such as 1602) needs to be driven, pins are insufficient, an output port can be expanded by using an integrated circuit 74HC595, just two single-chip microcomputers are supported by an SPI interface, the SPI serial interface can be used as the serial input of the 74HC595, and the liquid crystal display is driven by the parallel output of the 74HC595, which is a common typical application.

Although the device is used for potted plants, the device is also suitable for planting soil.

Claims (7)

1. A potting soil humidity monitoring device is characterized by mainly comprising a humidity sensing electrode carbon rod (20), a control box and a peristaltic pump (9); the control box takes an STC15 series single chip microcomputer or a single chip microcomputer ESP-12 with WIFI as internal processing control, and further comprises a soil humidity detection circuit, a peristaltic pump driving circuit, a liquid crystal display screen (1), a lower key (4) and an upper key (5);

two humidity sensing electrode carbon rods (20) are vertically buried at two sides of the flowerpot separately and are connected with the control box through two humidity sensing electrode connecting wires (7) and a humidity sensing electrode connecting plug (6); the peristaltic pump (9) is used for guiding water to the flowerpot through a peristaltic pump watering pipe (10), and a pump power supply wire plug (8) is connected with the control box; the control box is connected with 220V power supply through a power supply inlet wire plug (13); the control box displays the current soil humidity through the liquid crystal display screen (1), when the soil humidity reaches a lower threshold value, the intermittent automatic watering is started, and after the soil humidity detection for less than half an hour, the automatic watering is stopped to stabilize the soil humidity at the upper threshold value; that is, the upper and lower thresholds are defined as: the end value of the humidity range suitable for planting soil;

in the control box, a plurality of IO ports of the single chip microcomputer are connected with the liquid crystal display screen (1), the lower key (4) and the upper key (5), one IO port of the single chip microcomputer outputs square waves and is connected with the input end of the soil humidity detection circuit, and the ADC input end of the single chip microcomputer is connected with the output end of the soil humidity detection circuit; a plurality of output ports of the singlechip are also connected with a plurality of peristaltic pump driving circuits;

the key-down and key-up operation method comprises the following steps:

the upper key (5) has the following operating functions: pressing for a long time, namely pressing for more than 1 second, adding water, and stopping adding water when releasing; short pressing, namely pressing for no more than half a second, displaying an upper threshold, and after 2 seconds, restoring the current humidity display by numerical display; when entering an upper threshold setting mode and a lower threshold setting mode, an upper threshold setting mode indicator (2) or a lower threshold setting mode indicator (3) appears, at the moment, the short press is increased for a numerical value, the long press is saved for a threshold, the threshold setting mode exits, the threshold setting mode indicator disappears, and the numerical value display resumes the current humidity display;

the lower key (4) has the following operation functions: short pressing, namely pressing for no more than half a second, displaying a lower threshold, and after 2 seconds, restoring the current humidity display by numerical display; when entering an upper threshold setting mode and a lower threshold setting mode, reducing the short-time pressing value as a numerical value; long pressing, namely pressing for more than 1 second, entering an upper threshold setting mode, then long pressing into a lower threshold setting mode, and sequentially rotating, wherein a corresponding upper threshold setting mode indicator (2) or lower threshold setting mode indicator (3) appears, and the upper threshold or lower threshold is displayed; automatically quitting in a threshold setting mode without operation for 10 seconds;

lower threshold setting 0 indicates turning off watering, lower threshold setting 1 indicates watering is always on;

the soil humidity detection circuit comprises a triode Tr, a diode D, a resistor R0, a resistor R1, a resistor R2, a resistor R3, a capacitor C and a capacitor C1; the PWM square wave signal output by the singlechip is connected with one end of a resistor R3, the other end of the resistor R3 is connected with the base electrode of a triode Tr, the collector electrode of the triode Tr is connected with one end of a resistor R1, the other end of the resistor R1 is connected with +12V, the collector electrode of the triode Tr is also connected with one end of a resistor R0, and the other end of the resistor R0 is respectively connected with one end of a capacitor C and the anode of a diode D and is marked as a point T; the other end of the capacitor C is connected with one pole of a humidity sensing electrode carbon rod (20), the other pole of the humidity sensing electrode carbon rod (20), the Tr emitter, one end of the capacitor C1 and one end of the resistor R2 are all grounded, the negative end of the diode D, the other end of the resistor R2 and the other end of the capacitor C1 are connected together to serve as the output end of the soil humidity detection circuit, and the output end is connected with the input end of the single chip microcomputer ADC;

or, the soil humidity detection circuit comprises a time-base circuit NE555, a diode D5, a resistor R4, a resistor R5, a resistor R0, a resistor R1, a resistor R2, a resistor R3, a capacitor C5, a capacitor C and a capacitor C1; the 2 and 6 pins of the NE555, one ends of a capacitor C5, a resistor R4 and a resistor R5 are connected together, the other end of the resistor R5 is connected with the anode of a diode D5, the cathode of a diode D5, the other end of a resistor R4 and the 3 pin of the NE555 are connected together, the 8 pin of the NE555 is connected with one end of a resistor R1 to be +12V, the other end of the resistor R1, one end of a resistor R0 and the 7 pin of the NE555 are connected together, the other end of the resistor R0 is respectively connected with one end of the capacitor C and the anode of the diode D to be marked as a point T, the other end of the capacitor C is connected with one pole of a humidity sensing electrode carbon rod (20) and the other pole of the humidity sensing electrode, the other end of the capacitor C5, the pin 1 of the NE555, one end of the capacitor C1 and one end of the resistor R2 are all grounded, the negative end of the diode D, the other end of the resistor R2 and the other end of the capacitor C1 are connected together to serve as the output end of the soil humidity detection circuit, and the output end is connected with the input end of the singlechip ADC;

the humidity sensing electrode carbon rod (20) is a circle of conductive metal ring tightly wrapped at one end of the carbon rod, a humidity sensing electrode connecting wire (7) is pressed or welded through the conductive metal ring, and resin is coated or plastic package is carried out on the conductive metal ring;

or the humidity sensing electrode carbon rod (20) is formed by electroplating a layer of metal on one end of the carbon rod, welding a humidity sensing electrode connecting wire (7) on the metal coating, and coating plastic or potting resin on the metal coating and the root of the welding wire;

the peristaltic pump driving circuit comprises an NPN triode T8, a P-type MOS tube pMos, a diode D8, a capacitor C8, a resistor R8, a resistor R81 and a resistor R82; one output port of the singlechip is connected with one end of a resistor R8, the other end of the resistor R8 is connected with a base electrode of an NPN triode T8, a collector electrode of an NPN triode T8 is connected with one end of a resistor R82, the other end of the resistor R82 and one end of a resistor R81 are connected with a grid electrode of a P-type MOS tube pMos, the other end of the resistor R81 and a source electrode of the P-type MOS tube pMos are connected together to +12V strong current, a drain electrode of the P-type MOS tube pMos is respectively connected with one end of a pump power supply line plug (8), the negative end of a diode D8 and one end of a capacitor C8, and the other end of the pump power supply line plug (8), the positive end of;

or the peristaltic pump driving circuit comprises an N-type Mos tube, a diode D8, a capacitor C8 and a resistor R8; one output port of the single chip microcomputer is connected with one end of a resistor R8, the other end of the resistor R8 is connected with the grid of the Mos tube, the source electrode of the Mos tube is grounded, the drain electrode of the Mos tube is respectively connected with one end of a pump power supply line plug (8), the positive end of a diode D8 and one end of a capacitor C8, and the other end of the pump power supply line plug (8), the negative end of the diode D8 and the other end of the capacitor C8 are connected together to be connected with +12V strong current;

when the control box takes a single chip microcomputer ESP-12 with WIFI as internal processing control, the single chip microcomputer ESP-12 with WIFI is connected with a mobile phone or a computer through a wireless network, the single chip microcomputer ESP-12 with WIFI is matched with LUA script language programming firmware of a NODEMCU, a selected program module comprises WIFI, NET, an MQTT protocol, a GPIO port and an SPI port for operation, and the remote Internet of things adopts the MQTT protocol;

when the control box is connected with the mobile phone or the computer, the display interface of the mobile phone or the computer is listed line by line in a list form: the current humidity, the upper threshold value and the lower threshold value correspond to one path in each row; clicking an upper threshold or a lower threshold to directly input numerical value modification at any time;

the mobile phone or the computer is connected with the control box through the WIFI and is divided into three networking modes:

in the mode 1, the single-chip microcomputer ESP-12 with WIFI in the control box is a WIFI AP webpage server, and a mobile phone or a computer is connected with the WIFI and is accessed to 192.168.4.1 by a browser; the mode can monitor humidity, and is mainly used for setting a singlechip ESP-12 with WIFI in a control box, so that the singlechip ESP-12 can be connected with a wireless router or available WIFI, including WIFI names and passwords, and displaying connected IP for connection in the following mode 2; in the method, the external network of the mobile phone or the computer is not connected, and only the mobile phone or the computer is used for setting a WIFI name and a password at the beginning of networking;

in the mode 2, a singlechip ESP-12 with WIFI in a control box is automatically connected with a wireless router or available WIFI, the WIFI name and the password are set in the mode 1 in advance, and the IP displayed after connection is recorded; the mobile phone or the computer is also connected with the wireless router or the available WIFI, and the control box can be connected at any time to monitor the humidity only by using the browser to access the recorded IP; in addition, a networking indicator light is added, and a control box mode 2WIFI connection is indicated to be successful;

mode 3, the control box comprises an internet of things MQTT protocol, and the mobile phone or the computer is remotely connected with the control box through the MQTT protocol to monitor the humidity.

2. A potting soil humidity monitoring device as claimed in claim 1, wherein the 12V operating voltage of the soil humidity detection circuit is changed to 5V, so that the resistance Rl can be reduced by times, and the device is suitable for moisture-proof planting detection; under the condition, the output of the switching power supply is 12V and 5V, and the 5V outputs 3.3V through the LDO type three-terminal regulator to supply working voltage to a singlechip or an ESP-12;

or a diode D in the soil humidity detection circuit is connected with a voltage stabilizing tube in series, so that the output voltage of the soil humidity detection circuit is reduced by the voltage stabilizing value of the voltage stabilizing tube, and the saturation value of the soil humidity is close to 0;

or the upper end of the resistor R2 is connected with a voltage stabilizing tube in series, and the humidity detection voltage is output from the connection point of the voltage stabilizing tube and the resistor R2, namely the connection point of the voltage stabilizing tube and the resistor R2 is connected with the input end of the single chip ADC, so that the output voltage of the soil humidity detection circuit is reduced by the voltage stabilizing value of the voltage stabilizing tube, and the soil humidity saturation value is close to 0;

the voltage-stabilizing tube is a Schottky diode with forward voltage drop of 0.3V, a common silicon diode with forward voltage drop of 0.6V, a patch voltage-stabilizing tube of 2.2V or a patch voltage-stabilizing tube of 3.3V.

3. A potting soil humidity monitoring device as claimed in claim 1, wherein the 220V transformer of the control box employs a quasi-resonant soft switching power supply; the 12V power supply has a current limit protection function.

4. A potting soil humidity monitoring device as claimed in claim 1, wherein the control box further comprises a beep buzzer and an LED indicator connected to the IO port of the single chip microcomputer, wherein the LED indicator is normally on when operating normally, and flashes when abnormal conditions occur, and the beep buzzer sounds.

5. A potting soil humidity monitoring device as claimed in claim 1, wherein connectors are added at the connection of the two humidity sensing electrode connecting wires (7) and the humidity sensing electrode connecting plug (6).

6. A potting soil moisture monitoring apparatus as claimed in claim 1, wherein the control box further comprises a mains switch connected in series to the power inlet of the mains plug (13).

7. A potting soil humidity monitoring device as claimed in claim 1, wherein the control box further comprises an integrated circuit 74HC595, an output pin of the 74HC595 being connected to the liquid crystal display (1), the single chip microcomputer being connected to a serial input pin of the 74HC595 through the SPI interface.

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