RU2844998C1 - Microcontroller measuring transducer for wireless soil sensors with function of exit from power-saving mode by radio signal from mobile objects - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: microcontroller measuring transducer for wireless soil sensors with function of exit from power-saving mode by radio signal from mobile objects comprises: microcontroller, capacitive sensor, reference resistor, first resistive voltage divider (RVD), radio transmitter, wherein the extreme leads of the first RVD are connected, respectively, to the first and second outputs of the microcontroller, and the middle lead is connected to the first input of the analogue comparator built into the microcontroller, output of pulse-width modulator of microcontroller is connected to input of radio transmitter, radio transmitter power lead is connected to third output of microcontroller, common lead of radio transmitter is connected to common lead of microcontroller, first leads of reference resistor and capacitive sensor are connected to second input of analogue comparator, reference resistor second lead is connected to microcontroller fourth output. Device comprises a radio receiver and a second voltage divider, wherein radio receiver output is connected to microcontroller awakening input, power lead of radio receiver is connected to power lead of microcontroller, first extreme lead of second RVD is connected to microcontroller fifth output, and the second extreme lead of the second RVD, the common lead of the radio receiver and the second plate of the capacitive sensor are connected to common lead of microcontroller.

EFFECT: broader functional capabilities.

1 cl, 1 dwg

Description

Field of technology to which the invention relates

The invention relates to measuring equipment, in particular to devices for measuring physical quantities using capacitive sensors, and can be used to build wireless systems for monitoring soil humidity and temperature.

State of the art

Irrigation machines do not take into account the actual moisture content of soil areas before irrigation. With subsequent irrigation of these areas, the difference in moisture content will increase, the crop yield across the field changes by 25-30% of the average values (Podlipnov, V.V. Experimental determination of soil moisture using hyperspectral images / V.V. Podlipnov, V.N. Shchedrin, A.N. Babichev, S.M. Vasiliev, V.A. Blank // Computer optics. - 2018. - Vol. 42, No. 5. - Pp. 877-884. - DOI: 10.18287/2412-6179-2017-42-5-877-884). Wireless soil moisture and temperature monitoring sensors (BDP) are required for automatic irrigation control systems.

In scientific research, unmanned aerial vehicles (drones) are used to collect data from UAVs, which allows limiting the power of radio transmitters built into the UAVs, and therefore their energy consumption. The data is stored by the drone's microprocessor system and can then be loaded into a computer for analysis (Holtorf, L.; Titov, I.; Daschner, F.; Gerken, M. UAV-Based Wireless Data Collection from Underground Sensor Nodes for Precision Agriculture. AgriEngineering 2023, 5, 338-354. https://doi.org/10.3390/ agriengineering5010022). Data collection from UAVs can be organized using sprinkler machines. The microcontroller measuring transducer (MMP) is the main element of the UAV, designed to convert the measured physical quantities into a digital code.

A device is known for measuring physical quantities using capacitive sensors, comprising first and second generators, a microcontroller (MC) and a digital indicator, in the timing circuits of the generators, a capacitive sensor and a reference capacitor are connected, respectively, the timing resistors are connected according to known circuits, the generator outputs are connected to the counting inputs of the corresponding MC counters, one of the MC outputs is connected to the generator generation enable inputs, the digital indicator is connected to the MC outputs (see Russian patent No. 2214610, class G01R 27/26).

The disadvantage of the known solution is the lack of a power saving function, which does not allow using this solution for building radio sensors operating from autonomous power sources.

Known is a capacitance and resistance MIP in binary code, comprising: MC, capacitive and resistive sensors, reference capacitor and resistor, resistive voltage divider (RVD), wherein the reference resistor and resistive sensor are connected with their first terminals to the first plates, respectively, of the capacitive sensor and reference capacitor, the middle terminal of the RVD is connected to the first input of the analog comparator (AC) built into the MC, the extreme terminals of the RVD are connected, respectively, to the power terminals of the MC, the first terminals of the reference resistor and resistive sensor are connected to the second input of the AC, the second terminals of the reference resistor and resistive sensor are connected, respectively, to the first and second outputs of the MC, the second plates of the capacitive sensor and reference capacitor are connected, respectively, to the third and fourth outputs of the MC (see Russian patent No. 2391677, cl. G01R 27/26).

The disadvantage of the known solution is limited functionality, there is no function of transmitting the result of the conversion via a radio channel and no energy saving function, the RDN continuously consumes energy from the MC power source. For the BDP, the energy saving function is one of the most important.

The closest in technical essence to the claimed technical solution and adopted by the authors as a prototype is a pulse-width modulator for resistive and capacitive sensors with transmission of the conversion result via a radio channel, comprising: an MC, a capacitive sensor, a reference capacitor, a resistive sensor, a reference resistor, a RDN, a radio transmitter, wherein the middle terminal of the RDN is connected to the first input of the AC, the first terminals of the sensors and reference elements are connected to the second input of the AC, and the second terminals of the sensors and reference elements are connected, respectively, to the first, second, third and fourth outputs of the MC, the extreme terminals of the RDN are connected, respectively, to the fifth and sixth outputs of the MC, the output of the pulse-width modulator of the MC is connected to the input of the radio transmitter, the power terminal of the radio transmitter is connected to the seventh output of the MC, the common terminal of the radio transmitter is connected to the common terminal of the MC (see Russian patent No. 2603937, cl. G01 R27/26).

The disadvantage of the known solution is the limited functionality of the MIP, namely, there is no function to wake up the MK from sleep mode from a signal from external sources, such as drones or irrigation machines, which limits the scope of use of the MIP in battery-powered BDPs for irrigation control systems in precision agriculture.

Disclosure of invention

The proposed solution comes down to expanding the functional capabilities of the device, namely, the function of waking the MC from sleep mode from signals from external mobile sources, such as robots, drones or sprinkler machines, has been implemented, which allows reducing the energy consumption of the MIP in the BDP, and, consequently, reducing operating costs associated with replacing the BDP batteries.

The technical result is achieved in that in the MIP for the BDP with the function of exiting the energy-saving mode by a radio signal from moving objects, comprising: MK, a capacitive sensor, a reference resistor, a first RDN, a radio transmitter, wherein the outer terminals of the first RDN are connected, respectively, to the first and second outputs of the MK, and the middle terminal is connected to the first input of the AC built into the MK, the output of the pulse-width modulator of the MK is connected to the input of the radio transmitter, the power supply terminal of the radio transmitter is connected to the third output of the MK, the common terminal of the radio transmitter is connected to the common terminal of the MK, the first terminals of the reference resistor and the capacitive sensor are connected to the second input of the AC, the second terminal of the reference resistor is connected to the fourth output of the MK, a radio receiver and a second RDN are additionally introduced, wherein the output of the radio receiver is connected to the wake-up input of the MK, the power supply terminal of the radio receiver is connected to the power supply terminal of the MK, the first outer terminal of the second RDN is connected to the fifth output of the MK, and the second extreme terminal of the second RDN, the common terminal of the radio receiver and the second plate of the capacitive sensor are connected to the common terminal of the MC.

Brief description of the drawings

The drawing shows a structural diagram of the MIP for the BDP with the function of exiting the energy-saving mode by a radio signal from moving objects.

Implementation of the invention

The MIP for the BDP with the function of exiting the energy-saving mode by a radio signal from moving objects contains (drawing): MK 1, radio receiver 2, first RDN 3, second RDN 4, reference resistor 5, radio transmitter 6 and capacitive soil moisture sensor 7.

The extreme terminals of the first RDN 3 are connected, respectively, to the first and second outputs of the MC, the middle terminal of the first RDN 3 is connected to the first input of the AC built into the MC (the AC is not shown in the drawing), the modulating input of the radio transmitter 6 is connected to the output of the pulse-width modulator of the MC (the pulse-width modulator is not shown in the drawing), the power supply terminal of the radio transmitter 6 is connected to the third output of the MC, the first terminals of the reference resistor 5 and the capacitive sensor 7 are connected to the second input of the AC, the second terminal of the reference resistor 5 is connected to the fourth output of the MC, the output of the radio receiver is connected to the wake-up input of the MC, the power supply terminal of the radio receiver 2 is connected to the power supply terminal of the MC, the first extreme terminal of the second RDN 4 is connected to the fifth output of the MC, the second extreme terminal of the second RDN 4, as well as the common terminals of the radio receiver 2 and the radio transmitter 6 are connected to the common terminal of the MC.

MIP for BDP with the function of exiting the energy-saving mode by radio signal from moving objects as follows.

MK 1 executes the algorithm sequentially step by step.

Step 1. The MK is in sleep mode. As soon as the radio receiver 2 sends a wake-up signal, the MK exits sleep mode.

Step 2. The MC outputs log.1 to the first output, and log.0 to the second output. The reference voltage Vref is formed at the middle output of the first RDN 3.

Step 3. The MC configures the second input of the AC to a digital output and outputs through it and the fourth output log.0, the capacitive sensor 7 is discharged over several periods of the MC clock generator.

Step 4. The MC configures the second input of the AC to an analog input, outputs log.1 through its fourth output, starts the clock counter and goes into the “Capture” event waiting mode.

Step 4. Capacitive sensor 7 is charged through the reference resistor Ro, as soon as the voltage on the capacitive sensor 7 equals the voltage Vref, then the AC changes the logical level at the output. According to this event, the binary code of the counter, proportional to the number of counted clock pulses, is copied to the memory by the MC.

Step 5. The MK insists on the second input of the AC as a digital output and outputs through it the fourth output log.0.

Step 6. The MC turns off the power supply of the first RDN by outputting log.0 to the first output.

Step 7. The MK connects the power supply of the second RDN by outputting log.1 to the fifth output.

Step 8. The MC executes the algorithm for converting the output voltage of the built-in analog temperature sensor into code using the built-in analog-to-digital converter and stores this code in memory.

Step 9. The MC turns off the power supply of the second RDN by outputting log.0 to the fifth output.

Step 10. The MC supplies power to the radio transmitter 6 by outputting log.1 through the third output and transmits the results of the transformations in the form of codes to the input of the radio transmitter 6, using the pulse-width modulator built into the MC.

Step 11. After transmitting data via the radio channel to the data collection system (DCS) (DCS is not shown in the drawing), the MC switches off the power supply of the radio transmitter 6 by outputting log.0 through the third output and goes into sleep mode.

The SSD from a plurality of BDPs distributed over the field can be placed on mobile objects, such as robots, drones, and sprinkler machines. The SSD receives data and stores it in memory according to the address (number) of the BDP. Since the following are known: voltage Vref, period of clock pulses MC, number of counted pulses, reference resistance Ro, the SSD calculates the value of the sensor capacitance Cx according to known formulas and determines the soil moisture in which the corresponding BDP is located according to the calibration table. The processed data are transmitted to the control system, for example, a sprinkler machine, which generates control signals for the executive mechanisms of irrigation control, and also archives and displays the data on the computer monitor in a form convenient for the user to perceive.

The proposed solution comes down to expanding the functional capabilities of the MIP, namely, the implementation of the function of exiting the MC from the energy-saving mode (sleep mode) by radio signals from external moving objects is provided, which makes it possible to use the proposed solution for building energy-efficient BDPs necessary in precision farming technologies for automating irrigation control systems.

Claims (1)

A microcontroller measuring transducer for wireless soil sensors with a function of exiting the energy-saving mode by a radio signal from moving objects, comprising: a microcontroller, a capacitive sensor, a reference resistor, a first resistive voltage divider (RVD), a radio transmitter, wherein the outer terminals of the first RVD are connected, respectively, to the first and second outputs of the microcontroller, and the middle terminal is connected to the first input of an analog comparator built into the microcontroller, the output of the pulse-width modulator of the microcontroller is connected to the input of the radio transmitter, the power terminal of the radio transmitter is connected to the third output of the microcontroller, the common terminal of the radio transmitter is connected to the common terminal of the microcontroller, the first terminals of the reference resistor and the capacitive sensor are connected to the second input of the analog comparator, the second terminal of the reference resistor is connected to the fourth output of the microcontroller, characterized in that it additionally contains a radio receiver and a second RVD, wherein the output of the radio receiver is connected to the wake-up input of the microcontroller, the power terminal the radio receiver is connected to the power supply output of the microcontroller, the first extreme output of the second RDN is connected to the fifth output of the microcontroller, and the second extreme output of the second RDN, the common output of the radio receiver and the second plate of the capacitive sensor are connected to the common output of the microcontroller.