CN114803220A

CN114803220A - Intelligent garbage can based on Internet of things and multi-mode sensing technology and using method thereof

Info

Publication number: CN114803220A
Application number: CN202210486299.0A
Authority: CN
Inventors: 方洛; 方潮铭; 廖世濛; 张磊; 林杉
Original assignee: Guangdong Bairun Health Technology Co ltd
Current assignee: Guangdong Bairun Health Technology Co ltd
Priority date: 2022-05-06
Filing date: 2022-05-06
Publication date: 2022-07-29
Anticipated expiration: 2042-05-06
Also published as: CN114803220B

Abstract

The invention discloses an intelligent garbage can based on the Internet of things and a multi-mode sensing technology and a using method thereof, and relates to the technical field of medical garbage cans. In the invention, multiple sensor technologies are integrated, so that the two-dimensional monitoring of the storage state of the garbage can is realized, and the garbage can is more favorable for realizing the active supervision of a garbage disposal system compared with the traditional garbage can; in addition, the interactive media with the user is supplemented, the packaging process when medical waste is put in is standardized by using the display screen to play propaganda and description videos, on one hand, the leakage risk caused by incorrect packaging is reduced, and on the other hand, the use threshold of the intelligent garbage can is reduced. The embedded printer is used for printing the receipt and the label, so that the type and the information of the medical waste can be accurately determined for each packet; the conditions of medical waste loss and malicious theft which possibly occur in the transportation process are avoided through mutual evidence recorded by the Internet of things platform, and the efficiency of medical waste management and treatment is improved.

Description

Intelligent garbage can based on Internet of things and multi-mode sensing technology and using method thereof

Technical Field

The invention relates to the technical field of medical trash cans, in particular to an intelligent trash can based on the Internet of things and a multi-mode sensing technology and a using method thereof.

Background

Many public places, such as hospitals, generate a large amount of waste every day, wherein the waste generated by hospitals, due to the nature of their services, carries contaminants such as pathogens, residual drugs and chemical agents, and needs to be properly recovered and disposed of.

But the trash cans in wide use today are very primitive: when in use, the trash can cover needs to be opened manually, so that a user is in contact with medical wastes; the garbage amount in the garbage can cannot be monitored in real time, cleaning and garbage recycling of the garbage can require daily inspection by cleaning personnel, and management is inconvenient; the content of harmful substances in the garbage can cannot be monitored in real time, and the health of public people and cleaning staff is harmed.

In recent years, the concept of intelligent trash cans has been proposed, i.e., the cover can be automatically opened and closed by proximity sensing; the Wangbuayan team in Jiangsu province's hospital optimizes the automatic uncovering process of the trash can based on the double photoelectric sensors and the electromechanical device (invention patent CN 109911467A). However, these improvements are still at a relatively rudimentary level, and there are problems such as failure to monitor whether the trash can lid is opened maliciously, failure to manage the type of trash, failure to predict the time required for the trash in the can to be reclaimed, etc.

Disclosure of Invention

The invention aims to provide an intelligent garbage can based on the Internet of things and a multi-mode sensing technology and a using method thereof, and aims to solve the technical problems that whether the garbage can cover is opened maliciously or not cannot be monitored, the garbage types cannot be managed, and the time for recovering and processing the garbage in the can cannot be predicted.

In order to achieve the purpose, the invention adopts the following technical scheme: intelligence garbage bin based on thing networking and multimode sensing technology includes: the intelligent garbage bin comprises an inner barrel, a shell, a garbage bin cover, a control core, an Internet of things module, a weighing module, a distance measuring module, a printer, a fingerprint identification module, an automatic cover opening module, an SD card module and a touch display screen module; the inner barrel is used for containing garbage; the outer shell is sleeved on the periphery of the inner barrel; the garbage can cover is hinged to the shell and used for sealing the opening of the shell; the control core is arranged on the barrel wall of the shell and used for controlling the work of the modules; the Internet of things module is used for connecting the Internet of things platform and the control core and providing a communication channel between the embedded system and the Internet of things platform, the embedded system is used for completing data interaction with the cloud server through an API (application programming interface) provided by the Internet of things platform, and the Internet of things platform issues data reading and writing instructions through corresponding API interfaces; the weighing module is electrically connected with the control core and the Internet of things module, is arranged at the bottom of the inner barrel and is used for monitoring the weight of the garbage in the inner barrel; the distance measuring module is electrically connected with the control core and the Internet of things module, is arranged in the middle of the garbage can cover and is used for measuring the distance to the inside of the garbage can so as to monitor the volume of garbage in the inner can; the printer is electrically connected with the control core and the Internet of things module and is used for printing a receipt for putting garbage into a user and cleaning the garbage by a cleaner; the fingerprint identification module is electrically connected with the control core and the Internet of things module, is arranged on the outer wall of the shell and is used for comparing identity information of an operator during uncovering; the automatic uncovering module is electrically connected with the control core and the Internet of things module, is arranged at a connecting shaft between the shell and the garbage can cover and is used for automatically opening and closing the garbage can cover according to the control of the control core; the SD card module is electrically connected with the control core and the Internet of things module and is used for storing data to be displayed and storing an operation diary of the embedded system; the touch display screen module is electrically connected with the control core and the Internet of things module, and is used for displaying the real-time state and the detected physical quantity of the embedded system and providing the human-computer interaction functions of video playing, two-dimension code display and touch control.

As an optional embodiment, in the first aspect of the present invention, the weighing module is provided with a strain type pressure sensor as a weighing bracket, and cooperates with a 24-bit AD conversion module HX711 chip to implement the measurement of the weight of the garbage, the weighing bracket is mounted at the bottom inside the housing, the inner barrel is placed on the weighing bracket, and the weight of the inner barrel completely acts on the weighing bracket; the strain type pressure sensor comprises four strain gauges arranged in an array mode, wherein two strain gauges are deformed to reduce the resistance value, and the other two strain gauges are deformed in a tensile mode to increase the resistance value; the four strain gauges form a full-bridge circuit on the circuit connection, excitation voltage is input to one diagonal node, a corresponding voltage value is output to the other diagonal node, and the voltage value is in direct proportion to the bearing pressure of the bracket; the HX711 chip is connected with the full bridge circuit in the weighing bracket by four leads, and each lead is connected to a node of the full bridge circuit; two wires apply voltage excitation; two output measurement effective voltage values are collected by an HX711 chip and subjected to analog-to-digital conversion; the HX711 chip is connected with the main control chip of the control core through two signal lines which comprise a synchronous clock line PD _ SCK and a data line DOUT, the two signal lines are connected to any two independent digital IO pins on the main control chip, and the HX711 chip is communicated with the main control chip through a private digital protocol of the HX711 chip.

As an optional embodiment, in the first aspect of the present invention, the ranging module is a TOF10120 laser ranging module, a measurement surface of the ranging module is installed in the barrel, the ranging module and the main control chip of the control core communicate with each other by using a standard IIC protocol, and the ranging module and the main control chip of the control core are connected by 2 signal lines in total, including a synchronous clock line SCL and a data line SDA.

As an optional embodiment, in the first aspect of the present invention, the control core further includes a lithium battery, a power supply circuit, an anti-reverse connection circuit, an anti-surge current circuit, a crystal oscillator circuit, a false sh module, and a button battery; the lithium battery is a 7.4V rechargeable lithium battery and is used for providing electric energy for the control core; the power supply circuit is based on a synchronous buck converter, and converts an input power supply into a voltage required by an embedded system with the power supply efficiency of more than 90%; the reverse connection preventing circuit adopts a PMOS tube and is used for preventing the control core from being damaged due to the reverse connection misoperation of the battery; the anti-surge circuit is based on a transient suppression diode (TVS) and is used for providing effective protection for potential electrostatic discharge (ESD); the crystal oscillator circuit comprises a 25MHz system crystal oscillator and a 32.768kHz Real Time Clock (RTC) crystal oscillator, and the 25MHz system crystal oscillator is used for providing a reference clock required by the work for the embedded system; the Real Time Clock (RTC) crystal oscillator of 32.768kHz is used for saving time information and key data of the system when the power is down; the button battery is used for providing electric energy for a real-time clock and key data storage when the embedded system is powered off or enters a low power consumption mode; the FLASH module is used for storing a Chinese character library and providing a Chinese character display function for the touch display screen module.

As an alternative embodiment, in the first aspect of the present invention, the lithium battery is connected to the ADC pin of the main control chip through a voltage dividing circuit, and is used for monitoring the battery capacity in real time.

As an alternative embodiment, in the first aspect of the present invention, the housing is provided with an electromagnetic shielding cover, the electromagnetic shielding cover encloses the control core and the module of internet of things, and an antenna of the module of internet of things protrudes to the outside of the electromagnetic shielding cover.

As an alternative embodiment, in the first aspect of the present invention, each module has a corresponding LED operation status indicator, and when the module operates normally, the corresponding LED operation status indicator lights up; when the module does not work, the LED working state indicator lamp is turned off.

The invention discloses a use method of an intelligent garbage can based on the Internet of things and a multi-mode sensing technology in a second aspect, and the use method is applied to the intelligent garbage can based on the Internet of things and the multi-mode sensing technology in the first aspect and comprises the following steps:

s0, before the embedded system is powered on, the burning of the FLASH word library file is completed, simultaneously the contents to be displayed on the display screen are written into the SD card, and the identity information of the related personnel is registered and temporarily stored in a FLASH module of the control core;

s1, electrifying the embedded system, and controlling a core main control chip to complete initialization of the printer, the weighing module, the ranging module, the touch display screen module, the fingerprint identification module, the automatic uncovering module and the SD card module;

s2, the embedded system actively configures an Internet of things module; firstly, carrying out power-on inspection to determine that the Internet of things module is successfully started; then, signal quality inspection is carried out to determine the attachment state of the PS domain of the module; then, subscribing objects and resources, and then logging the module on a physical network platform; if the login cannot be successfully carried out within the specified time, the module is restarted by pulling down the reset pin, and then the S2 flow is executed until the module is successfully logged in;

and S3, since the NB-IoT module has a survival time limit after successful login, the Internet of things platform is forced to take the module off line beyond the time range. Therefore, the embedded system sends a survival time updating command at intervals to update the survival time of the module, so as to ensure that the module is in a real-time online state;

s4, after all modules are initialized, the system enters a normal working mode; a display screen of the touch display screen module displays related data and related parameters of the last garbage input;

s5, when the garbage needs to be put into the garbage can, the fingerprint identification module reads the fingerprint of the operator for identity verification; the two-dimensional code interface is automatically called out through the verified touch display screen module, the two-dimensional code is used for an operator to scan and fill in the department and garbage type information generated by medical garbage, the physical network platform automatically compares the garbage type information with the data in the database, and if the comparison is successful, an permission instruction is released to the embedded system by using the Internet of things module;

s6, when the embedded system receives an approval instruction issued by the physical network platform, the control core controls the stepping motor of the automatic uncovering module to rotate forward to open the trash can cover; the embedded system measures the characteristics of the garbage in the current inner barrel through the weighing module and the distance measuring module, simultaneously uploads the weight of the medical waste, the volume information of the medical waste and the information of operators which are put into the barrel at this time through the physical network platform, and calls a printer to print the weight of the medical waste, the volume of the medical waste and the information of the operators which are put into the barrel at this time;

s7, after the garbage throwing operation is completed, the touch display screen receives closing operation, the stepping motor of the automatic cover opening module rotates reversely, and the garbage can cover is closed and locked;

s8, the system repeats the steps S4 to S8.

As an alternative embodiment, in the second aspect of the present invention, before the touch display receives the closing operation in step S7, the method further includes the following steps: judging the type of the input medical waste according to the mass/volume ratio of the input garbage; if the type of the input garbage is judged to be consistent with the type of the medical waste collected by the garbage can, receiving closing operation by the touch display screen; if the type of the input garbage is judged to be inconsistent with the type of the medical waste collected by the garbage can, a confirmation window is filled out by the touch display screen for an operator to confirm.

As an alternative embodiment, in the second aspect of the present invention, in step S6, when the weighing module detects that the weight of the inner barrel exceeds the set threshold and/or the distance measuring module detects that the current volume of waste exceeds the set threshold, the embedded system sends a full barrel alarm to the internet of things platform, and the internet of things platform pushes the full barrel alarm to the corresponding mobile terminal of the operator.

Compared with the prior art, the embodiment of the invention has the following beneficial effects:

the garbage can monitoring system integrates various sensor technologies, realizes two-dimensional monitoring on the storage state (garbage weight and volume) of the garbage can, and is more beneficial to realizing active supervision of a garbage treatment system compared with the traditional garbage can; the integrated circuit design enables the system to have considerable independence, and the system can be sold as an independent garbage can system and can be normally used without a complex sensor networking debugging process;

the interactive media with the user has been supplemented, and the encapsulation flow when medical waste puts in has been standardized with the explanation video to the display screen broadcast propaganda, has reduced because of the incorrect leakage risk that causes on the one hand, and on the other hand has reduced the study of intelligent garbage bin and has used the threshold. In addition, the embedded printer is used for printing the receipt and the label, so that the type and the information of the medical waste can be accurate to each package; the medical waste is prevented from being lost and maliciously stolen in the transportation process through mutual evidence recorded by the Internet of things platform, and the efficiency of managing and processing the medical waste is improved;

a code-scanning filling type garbage throwing mode is adopted, so that a user can open the cover to throw garbage after filling concise information such as garbage types, garbage amount and the like, and the garbage thrown into the barrel can be tracked and traced;

an automatic cover turning system combining cloud control and garbage can state information is added, so that physical contact between a user and a garbage can is reduced, and disease transmission ways are reduced; on the other hand, the situation that the garbage is continuously put after the garbage bin is full is also reduced, the garbage overflow is reduced, and the normal closing of the garbage bin cover is ensured, so that the leakage of toxic and harmful gases, pathogens and the like of the garbage is reduced, and meanwhile, the garbage can is convenient for cleaning personnel to recover;

the identity of a garbage throwing person is ensured by adopting multiple authentication technologies (fingerprint identification, Internet of things software authentication and the like), the garbage can cover can be locked if the garbage throwing person fails to pass the authentication, and the medical wastes are prevented from being taken out maliciously or from being leaked due to irregular operation.

A large number of circuit innovation designs are used, and the normal function, the high robustness and the long service life of the intelligent garbage can are guaranteed. The simulation optimization is performed aiming at the ground plane impedance, the signal line and the like of the circuit structure, so that the system has better anti-noise interference capability and strong robustness to misoperation.

Data communication is based on an NB-IoT platform, and is directly administered by three operators, so that the mobile phone can access the network in places with mobile phone signals, a complex networking process and high networking expense are not needed, the system cost is favorably reduced, and the method is applied to hospitals in remote areas.

Drawings

FIG. 1 is a schematic diagram of the overall circuit structure of one embodiment of the present invention;

FIG. 2 is a graph of cell efficiency at different input voltages for one embodiment of the present invention;

FIG. 3 is a schematic diagram of the power-ground plane set impedance optimization results of one embodiment of the present invention;

FIG. 4 is an actual wiring diagram after completion of wiring optimization;

FIG. 5 shows cross talk between SDRAM signal lines when no wiring optimization is completed;

FIG. 6 shows the cross talk between SDRAM signal lines after the layout optimization is completed;

FIG. 7 is an eye diagram of the SDRAM signal lines after routing optimization is completed;

FIG. 8 is a schematic diagram of a BOOT pin setup circuit according to one embodiment of the present invention;

FIG. 9 is a schematic diagram of an initialization process of M5310-A according to one embodiment of the present invention;

FIG. 10 is a schematic diagram of an embedded system workflow according to one embodiment of the present invention;

FIG. 11 is a schematic diagram of an anti-reverse connection circuit according to one embodiment of the present invention;

FIG. 12 is a control core 3D simulation diagram of one embodiment of the present invention;

FIG. 13 is a GUI interface diagram according to the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention. Furthermore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features for distinguishing between descriptive features, non-sequential, non-trivial and non-trivial.

In the following, with reference to fig. 1 to 13, an intelligent trash can based on the internet of things and the multi-mode sensing technology according to an embodiment of the present invention is described, where hardware devices include an inner barrel, a housing, a trash can cover, a control core, an internet of things module, a weighing module, a distance measuring module, a printer, a fingerprint identification module, an automatic uncovering module, an SD card module, and a touch display screen module.

The inner barrel is an inner barrel body which is used for directly containing garbage in the intelligent garbage can, is in direct contact with the garbage, bears the weight of the garbage, and is convenient to take out of the garbage can for garbage dumping and cleaning;

the outer shell is sleeved on the periphery of the inner barrel; the outside casing of intelligent garbage bin promptly, the sensor module and the electronic component who mainly are used for protecting intelligent garbage bin provide good garbage bin vision simultaneously and look and feel, make things convenient for the transport and the management of garbage bin.

The garbage can cover is hinged to the shell and used for sealing the opening of the shell;

the control core is arranged on the barrel wall of the shell and used for controlling the work of the modules; the control core comprises a main control chip and a circuit control core board, and the main control chip is provided with an embedded system. Specifically, in this embodiment, the STM32F429IIT6 is adopted as the main control chip, and is a chip with

Bit

The CPU core integrates a floating point arithmetic unit (FPU) and a self-adaptive real-time Accelerator (ART), the working clock frequency reaches 180MHz, and the DSP instruction is supported; at the same time, removeBesides the on-chip memory FLASH, the chip also allows RAM devices such as SDRAM, NOR/NAND memory, etc. to be mounted outside the chip to expand the available memory of the memory. It integrates an LCD-TFT controller, with a fully programmable resolution (total width up to 4096 pixels, total height up to 2048 lines, pixel clock up to 83MHz), and a Chrom accelerator (DMA2D) for enhanced graphics content creation functionality; and meanwhile, the device supports an external backup power supply for supplying power to the RTC in sleep, stop and standby modes, is provided with a 20 x 32-bit backup register and an optional 4KB backup SRAM, and can be used for storing key operation data of the embedded system in the case of power failure. The chip also provides a channel DMA of data stream, supports FIFO and burst transmission, and can meet the requirement of high data transmission rate when the embedded system displays images.

The circuit control core board comprises a lithium battery, a power supply circuit, an anti-reverse connection circuit, an anti-surge current circuit based on a transient suppression diode (TVS), a crystal oscillator circuit, a FALSH module and a button battery;

preferably, the power circuit is based on a synchronous buck converter, and converts the input power into the voltage required by the embedded system with the power efficiency of more than 90%; in view of power supply, the system supplies power by adopting a lithium battery mode, so that the embedded system is not limited by the position of a 220V socket of the mains supply and can be placed at any required position. In this embodiment, a 7.4V rechargeable lithium battery is used for power supply, and a synchronous buck converter chip TPS561201 is used to implement conversion from 7.4V to 5V (system operating voltage). Compare in low dropout linear regulator (LDO), power efficiency can follow LDO < 70% promote to 90%, can improve the operating time of system greatly, reduces the phenomenon of generating heat of power chip simultaneously, reduces the conflagration risk.

Preferably, the anti-reverse connection circuit adopts a PMOS tube and is used for preventing the control core from being damaged due to the reverse connection misoperation of the battery; as shown in fig. 11, when the power supply is normally connected, because the PMOS transistor has a parasitic diode, the source voltage Vs is Vcc-0.7V, and the gate voltage Vg is 0V, at this time, the absolute value of the gate-source voltage Vgs is greater than the threshold voltage Vth, the PMOS transistor is turned on, and current flows through the MOS transistor, so that the voltage drop between the drain D and the source S is reduced, and the reverse connection preventing circuit does not function; when the power supply is reversely connected, the source voltage Vs is-0.7V, the grid voltage Vg is Vcc, the conduction condition cannot be met, the PMOS tube is closed, no current flows through the circuit, and the reverse connection prevention circuit starts to play a role. The resistor R1 positioned on the grid can avoid the condition of overlarge grid current, thereby protecting the PMOS tube; and a capacitor C1 is added between the drain D and the ground, so that the speed of Vo voltage rising during power-on is delayed while filtering the input voltage, the effect of cold start is achieved, the damage to a system caused by overshoot current at the moment of battery access is prevented, and further the subsequent circuit is protected.

Preferably, the anti-surge circuit is based on transient suppression diodes (TVS) for providing effective protection against potential electrostatic discharge risks (ESD); during the manufacturing or transportation of the circuit control core board, the circuit control core board may accumulate charges due to friction, which may cause an ESD phenomenon. The ESD phenomenon will flow through the power-ground plane of the core board at the moment of power-on, causing a great impact on the devices connected to the power-ground plane, and causing damage to the related chips. The TVS tube can automatically and rapidly reduce the self impedance when two ends are impacted by instantaneous high energy, and absorb transient large current while clamping the voltage between the two ends at a preset value, thereby ensuring that circuit elements connected on a power supply-ground plane are not damaged by the impact of transient high energy.

Preferably, the crystal oscillator circuit comprises a 25MHz system crystal oscillator and a Real Time Clock (RTC) crystal oscillator of 32.768kHz, and the 25MHz system crystal oscillator is used for providing a reference clock required by the embedded system; the Real Time Clock (RTC) crystal oscillator of 32.768kHz is used for saving time information and key data of the system when the power is down. The button cell is used for providing a power supply for a real-time clock and key data storage when the system is powered off or enters a low power consumption mode. The FLASH module is used for storing a Chinese character library and providing a Chinese character display function for the touch display screen module.

As a preferred embodiment, because the intelligent garbage can relates to SDRAM, LCD and a main control chip with 180MHz working frequency, each high-speed module can generate instantaneous current related to the working frequency band when in work, and the instantaneous current flows through the impedance between the power supply and the ground plane to cause the voltage difference between the power supply and the ground plane to change. If the voltage variation is too large, the embedded system will be abnormal or even broken down. When the operating frequency of the device exceeds 10MHz, signal integrity issues need to be carefully analyzed at the time of wiring. Too long wiring, too much impedance mutation on signal lines, and too much crosstalk between adjacent signal lines all cause serious distortion of signals received by a receiving end, resulting in error code phenomenon. Therefore, a power-ground plane that presents a good low impedance (<0.5 Ω) in the full operating band (100 kHz-180 MHz) will be an important prerequisite for the system to operate properly. After the wiring of the device is completed, the impedance between the power supply and the ground plane is optimized, and finally the impedance between the power supply and the ground plane is smaller than 0.5 omega in the full working frequency band (100 kHz-180 MHz) by adopting the capacitance combination with different capacitance values, so that the normal work of the system is ensured. The power-ground plane impedance optimization results are shown in fig. 3. In the embodiment, the wiring of the SDRAM and the LCD screen high-speed module is optimized correspondingly in terms of the length and impedance of the signal line: the length deviation of the signal wires of the SDRAM is controlled within 50 mils, the signal wires on adjacent layers can vertically pass through the signal wires, and the number of via holes on each signal wire is less than 2. Meanwhile, the gap between the signal lines is ensured to have enough copper (connected to the ground) to provide a return flow path of a high-frequency signal, the impedance of different signal lines is ensured to be consistent, and finally the related signal time delay and the crosstalk between the signal lines are controlled within an acceptable range. The related optimization results of the SDRAM are shown in fig. 4 to 7, fig. 4 shows the wiring condition of the core board after the optimization is completed, fig. 5 shows the magnitude of crosstalk voltage between SDRAM signal lines before the optimization (the maximum value is about 27mV), fig. 6 shows the magnitude of crosstalk voltage between SDRAM signal lines after the wiring optimization (the maximum value is about 6mV, the crosstalk between lines is reduced by more than 4 times), fig. 7 shows the line eye diagram condition of the SDRAM signal lines after the optimization is completed, it can be seen that the undershoot amplitude of the signal overshoot is less than 0.5V, and the normal operation of the circuit can be ensured; and the maximum delay between signal lines is 0.2ns which is far less than the working dominant frequency of SDRAM, thus ensuring the normal operation of the system. And the SDRAM module is connected to an FMC interface of the main control chip and used for expanding a system operation RAM, providing a large-capacity video memory space for an LCD screen and providing a memory space for normal operation of a graphical interactive interface (GUI).

The Internet of things module is used for connecting the Internet of things platform and the control core and providing a communication channel between an embedded system and the Internet of things platform, the embedded system is used for completing data interaction with the cloud server through an API (application program interface) provided by the Internet of things platform, and the Internet of things platform issues data reading and writing instructions through corresponding API interfaces; specifically, the internet of things module selects a mass-produced NB-IoT module M5310-a (produced by china internet of things limited), is connected to an asynchronous serial receiver/transmitter (USART) peripheral of the main control chip, and communicates with the main control chip by using a USART protocol.

The weighing module is electrically connected with the control core and the Internet of things module, is arranged at the bottom of the inner barrel and is used for monitoring the weight of the garbage in the inner barrel; specifically, the weighing module adopts a strain type pressure sensor as a weighing support, the weighing support is matched with a 24-bit AD conversion module HX711 chip to realize the measurement of the weight of the garbage, the weighing support is arranged at the bottom of the inner side of the shell, the inner barrel is placed on the weighing support, and the weight of the inner barrel completely acts on the weighing support; the strain type pressure sensor comprises four strain gauges arranged in an array mode, when a frame body of the weighing support is manufactured, the strain gauges are poured into the frame body of the weighing support to form the weighing support, two strain gauges deform under pressure to reduce the resistance value, and the other two strain gauges deform under tension to increase the resistance value; the four strain gauges form a full-bridge circuit on the circuit connection, excitation voltage is input to one diagonal node, a corresponding voltage value is output to the other diagonal node, and the voltage value is in direct proportion to the bearing pressure of the bracket; the HX711 chip is connected with the full bridge circuit in the weighing bracket by four leads, and each lead is connected to a node of the full bridge circuit; two wires apply voltage excitation, two output measurement effective voltage values are collected by an HX711 chip and are subjected to analog-to-digital conversion; the HX711 chip is connected with the main control chip of the control core through two signal lines which comprise a synchronous clock line PD _ SCK and a data line DOUT, the two signal lines are connected to any two independent digital IO pins on the main control chip, and the HX711 chip is communicated with the main control chip through a private digital protocol of the HX711 chip.

The distance measuring module is electrically connected with the control core and the Internet of things module, is arranged in the middle of the garbage can cover and is used for measuring the distance to the inside of the garbage can so as to monitor the volume of garbage in the inner can; particularly, the inner barrel is cylindrical, namely the cross sectional area of the inner barrel at any height is the same; or a round table shape, namely the cross section area of the inner barrel is small at the bottom and large at the top, and the area change rate is constant. The residual capacity of the garbage can be calculated by a simple formula on the basis of the distance h from the upper surface of the garbage in the inner barrel to the distance measuring module, and the specific formula is determined according to the shape and the size of the inner barrel. Therefore, the real-time monitoring of the volume of the garbage in the garbage can is realized, and the early warning of the full garbage can is provided. Specifically, the distance measurement module is a ToF10120 module, and has the advantages of small size, high reliability and the like. It is connected to the interface of the interactive integrated circuit (I2C) of the main control chip and communicates with the main control chip through the I2C protocol.

The printer is electrically connected with the control core and the Internet of things module and is used for printing a receipt for putting garbage into a user and cleaning the garbage by a cleaner; specifically, the printer is a high-quality library 5820 thermal printer which is connected to a USART peripheral of the main control chip and communicates with the main control chip by adopting a USART protocol.

The fingerprint identification module is electrically connected with the control core and the Internet of things module, is arranged on the outer wall of the shell and is used for comparing identity information of an operator during uncovering; specifically, the fingerprint identification module is an AS608 chip, is connected to an asynchronous receiver/transmitter (UART) peripheral of the main control chip, and communicates with the main control chip by using a UART protocol. And provides WAK pins for waking up the embedded system in a low power consumption state.

The automatic uncovering module is electrically connected with the control core and the Internet of things module, is arranged at a connecting shaft between the shell and the garbage can cover and is used for automatically opening and closing the garbage can cover according to the control of the control core; specifically, the automatic uncovering module comprises a stepping motor and is directly powered by a 7.4V lithium battery, and a control line (signal line) of the automatic uncovering module is connected to the external periphery of a timer of the main control chip. The rotation angle direction of the stepping motor is controlled by the PWM wave with the adjustable duty ratio generated by the external timer, so that the processes of opening and closing the cover are realized.

The SD card module is electrically connected with the control core and the Internet of things module and is used for storing data to be displayed and storing an operation diary of the embedded system;

the touch display screen module is used for displaying the real-time state and the detected physical quantity of the embedded system and simultaneously providing the human-computer interaction functions of video playing, two-dimensional code display and touch control. Preferably, the touch display screen module selects a TF card with a smaller size and a larger capacity, so as to conveniently expand the storage space and play more contents. The SD card is connected to an SDIO interface of a main control chip, and the read-write operation of the SD card is managed through an SDIO peripheral of the main control chip.

Preferably, each module has a corresponding LED operation status indicator light, which is turned on when the module is in normal operation and turned off when the module is not in operation. The warning device can remind maintenance personnel of the fault and is convenient to maintain.

Preferably, the lithium battery is connected to an ADC pin of the main control chip through a voltage divider circuit, and an Analog Watchdog (AWDG) is used to detect the electric quantity of the battery in real time, so as to prevent fire caused by overdischarge or overcharge of the battery. Specifically, two ends of the positive electrode and the negative electrode of the battery are connected with a voltage division circuit and are connected to an ADC pin of the main control chip. In the program, a simulated watchdog interrupt is configured, and high and low electric quantity alarm thresholds are set. The ADC peripheral can automatically detect the real-time battery power without passing through the CPU, and threshold comparison is completed in the peripheral. The method can automatically finish the detection of the electric quantity of the battery under the condition of not occupying CPU resources (namely not influencing the normal work of the system). When the residual voltage of the battery is less than 7V, the ADC peripheral generates an analog watchdog interrupt, after receiving the interrupt, the embedded system firstly reports the low-power alarm of the OneNET platform through the M5310-A module, and stores key operation data (medical waste information, M5310-A networking conditions and the like) into a 4KB backup SRAM, and then the system automatically cuts power down to enter a low-power-consumption mode so as to slow down the power consumption speed of the battery and protect the battery. Meanwhile, the OneNet platform pushes information to relevant operators through mobile phones to remind the relevant operators to replace the lithium battery in time.

Preferably, the BOOT address of the embedded system is specified by a BOOT pin, and the BOOT pin setting circuit is shown in fig. 8. When the 4 th rising edge of the system clock (SYSCLK) arrives after the main control chip is restarted, the level of the BOOT pin is latched, and the main control chip sets the starting address of the program according to the level. The level of the BOOT pin of the main control chip at the moment of power-on is set, so that the main control chip can be selected to be started from FLASH, a system memory and an on-chip SRAM. Here, we choose to start from FLASH, so connect two BOOT pins to ground, and connect to chip main power supply rail (VCC) through a resistor, and form an RC network with parasitic capacitance in the pin and external filter capacitance C, further improve the reliability of system start under strong noise environment. The BOOT pin setting circuit is shown in fig. 8, and the BOOT addresses under different BOOT configurations are shown in table 1.

TABLE 1

BOOT1	BOOT0	Start address
			X
	0	User FLASH
			0	1	System memory
1	1	Built-in SRAM

When the embedded system needs to be debugged, the level of the BOOT pin can be adjusted to start from different addresses of the memory of the main control chip, so that the configuration of the main control chip (such as modifying running codes) is realized.

In the present invention, in order to better perform task management of a plurality of processes, an embedded system uses a Real Time Operating System (RTOS) for allocating a CPU to a plurality of tasks. Referring to fig. 9 and 10, the present embodiment will describe the embedded system software workflow after the system is powered on. After the system is powered on, the program is started from a base address (0x08000000, which is located in a FLASH), and the following steps are sequentially carried out:

firstly, configuring a system clock, selecting an external quartz crystal oscillator HSE as a clock source, firstly carrying out frequency division by 15, entering a Main phase-locked loop (Main PLL), configuring a frequency multiplication coefficient to be 216, then carrying out frequency division by 2 so that the system clock is 180MHz, and providing clock information for an AHB bus, an APB1 bus and an APB2 bus after carrying out corresponding frequency division. Therefore, all the peripheral devices of the main control chip obtain corresponding clock sources.

And secondly, initializing USART peripherals communicated with the M5310-A module. And sequentially sending instructions to the M5310-A module, checking whether the module is powered on and started successfully, judging the signal quality, and judging the login condition of the module. If the module is logged on the OneNET platform, the module is logged off, and the next operation is carried out. And then, setting a module side equipment registration code, subscribing Object resources and Resource resources, and finally logging in the module. After completing any operation, the M5310-A module will return OK command; if an instruction fails to complete, an ERROR instruction is returned. Within the delay time (10 seconds) specified by the operating system, if the module always returns the ERROR instruction, the M5310-A module is considered to be in fault. At the moment, the main control chip pulls down the RST pin of the M5310-A chip for 100ms to reset the module, and the module is automatically restarted through software; and then repeating the first step to the second step until the initialization process of the M5310-A module is completed. The M5310-A initialization flow is shown in FIG. 10.

And thirdly, configuring a universal IO port (used for controlling the LED and the weighing module), an LTDC peripheral, an FMC controller, a real-time clock peripheral, an SDIO peripheral, a DMA2D accelerator, an SPI1 peripheral, an ADC peripheral, a USART peripheral connected with a thermal printer, an I2C peripheral connected with a fingerprint identification device in sequence, configuring DMA and interrupting, starting a real-time operating system and the like. And when the initialization process of any step is abnormal, error information is returned, and the information is reported to the OneNet platform through the M5310-A module after all the peripheral equipment is initialized, so that an equipment operator is reminded to check whether the corresponding module has a fault in time. After the device completes self-check, it will enter the main GUI interface, as shown in fig. 13: the key with the functions of measuring the weight and volume of the current waste and correlating the weight and volume of the current waste.

And fourthly, the video (such as how to pack medical waste) stored in the SD card is guided into a pre-opened video memory space in the SDRAM through a DMA channel, and the LTDC peripheral controls the LCD screen to be quickly refreshed to realize the video playing function. The display screen continuously plays an operation guide and a propaganda video, and a user can independently learn the using method of the intelligent garbage can and related knowledge of garbage classification and garbage management after approaching the garbage can;

and fifthly, after all modules are initialized, the system enters a normal working mode. The working mode can be switched by a button on the main GUI interface, such as: and displaying corresponding video (such as medical waste sealing method video) and related parameters (weight, volume and the like) of the garbage. Under the management of a real-time operating system, the CPU switches back and forth among different tasks, and the maximum utilization efficiency is realized.

And sixthly, before the operator puts the garbage into the garbage can, the working mode can be switched through a button on the main GUI interface, and the fingerprint identification module is firstly utilized to carry out identity verification. When the effective fingerprint input is captured by the fingerprint identification module, the video playing is suspended, and meanwhile, the authentication two-dimensional code interface is called out. Then, an operator scans the two-dimensional code through a mobile phone, and the Internet of things platform transfers a video pause instruction. The garbage throwing report is displayed on the touch screen, and a user can fill information such as departments, types and the like generated by medical waste in the mobile phone or the touch display screen. After the operator fills in corresponding information, the OneNet platform automatically compares the data in the database, and a uncovering permission instruction is transferred to the embedded system through the M5310-A module after the comparison is successful.

And seventhly, if and only if the embedded system receives an approval instruction issued by the OneNET platform, the uncovering module is unlocked under the conditions that the residual capacity of the garbage can is sufficient, the maximum total weight distance of the current garbage meets a certain difference value, and no additional opening limit instruction exists, and the operator pastes the paper slip on the garbage bag to be thrown in. And then, the main control chip starts PWM output to control the stepping motor module, the cover of the garbage can is opened in a forward rotation mode, and an operator puts medical wastes into the garbage can. The main control chip controls the weighing module and the distance measuring module to measure the characteristics of the garbage in the current barrel, and meanwhile, the weight and the volume of the medical waste which is input at this time are uploaded through the NB-IoT platform. After the completion, the system prints the department and time for inputting medical wastes, and the volume and quality of the garbage input at this time, and an operator attaches the system to the garbage and makes relevant records of garbage input at the same time.

Eighth, preferably, the system will make a rough judgment on the type of medical waste input based on the mass/volume ratio of the input waste. If the system judges that the type of the input garbage is inconsistent with the type of the medical waste to be collected by the garbage can (if the needle is mistakenly thrown into a common garbage bag, the garbage bag can be punctured, and the medical waste is leaked), the system requires an operator to confirm.

And ninthly, after finishing the garbage throwing operation, the operator performs closing operation on the touch display screen. At the moment, the stepping motor rotates reversely to close and lock the garbage can cover, so that the garbage can is prevented from being opened accidentally, medical waste pollution is avoided, and potential safety hazards are brought to medical staff.

The invention provides a method for permitting the update of operator information as a preferred scheme. When the operation permission personnel needs to be updated, the administrator authentication information is firstly input into the touch display screen module to enter an administrator mode. And then the identity information (fingerprint) of the operation permission personnel to be updated is input into a fingerprint library file of the SD card. On the other hand, the operation licence information to be updated also needs to be input on the OneNET platform in the background. The double authentication mode of the platform of the Internet of things for releasing the unlocking instruction and the fingerprint authentication of the embedded system can effectively reduce the possibility of maliciously obtaining the uncovering permission of the trash can.

As a preferred scheme, the invention adds a timer which counts down for 1 hour in the embedded system. Wherein, the countdown duration of the timer is reset every time operation (touch of the touch screen, garbage input and the like) is performed. Within one hour after no user has been operating, the system will automatically enter a low power mode. Before the system enters the low power mode, critical data (medical waste information, M5310-a networking conditions, etc.) is written into the 4KB backup SRAM so that relevant data is not lost after power is lost. After the system enters the low power consumption mode, the system clock is stopped vibrating, and the clocks of all the peripheral equipment are closed, so that the power consumption of the system is reduced as much as possible. After the system enters the low power consumption mode, the touch screen sends an interrupt signal by touching the touch display screen. The main control chip exits the low power consumption mode after receiving the interrupt signal, provides a clock for the peripheral again, reconfigures the M5310-A module to log in the OneNET platform, and reads out the data stored in the 4KB backup SRAM.

As a preferred scheme, the invention designs full bucket alarm logic in the embedded system. When the embedded system detects that the weight of the barrel exceeds a set threshold value through the weighing module or detects that the volume of the current waste exceeds the set threshold value through the laser ranging module, the embedded system actively sends a full barrel alarm to the OneNet platform through the M5310-A module. After receiving the full-barrel alarm, the OneNet platform pushes the alarm to a mobile phone of a related operator to remind the operator to empty the garbage can in time.

As a preferred scheme, when medical wastes (such as needles) are thrown in the garbage can, an operator unlocks the cover of the garbage can by scanning the two-dimensional code, inputting department information and verifying identity. After the operator puts in the rubbish, the embedded system measures the weight and the volume of the rubbish put in this time, and judges the type of the medical waste put in according to the mass/volume ratio of the rubbish put in; if the type of the input garbage is judged to be consistent with the type of the medical waste collected by the garbage can, the touch display screen receives closing operation, an operator prints a receipt on the printer, the receipt is pasted on the input garbage, and relevant records are made. If the type of the input garbage is judged to be inconsistent with the type of the medical waste collected by the garbage can, a confirmation window is filled out by the touch display screen for an operator to confirm. Thus avoiding the mistaken input of medical articles. After confirmation, the touch display screen receives closing operation, an operator prints the receipt on the printer, and pastes the receipt on the input garbage, and relevant records are made.

When the garbage bin is full, the manager can receive the information of the full garbage bin and contact the garbage transfer personnel to clean the garbage bin. The numerical value of garbage bin actual weight and platform record will be compared to the transportation personnel when transporting to whether the abnormal conditions (medical waste loses or maliciously puts in etc.) appear in the inspection with reference to operating personnel's operation record. Then, according to the information of the type, weight, volume and the like of the garbage in the barrel, the garbage is transported to a relevant processing place for centralized processing. After the garbage can is emptied, related personnel can sterilize the garbage can, and cross infection is avoided.

As a preferred scheme, the invention allows the OneNet platform to actively issue a reading instruction to read the garbage information in the bucket. After receiving the reading instruction of the OneNET platform, the embedded system controls the weighing module and the laser ranging module to read the garbage information in the current barrel and reports the garbage information to the OneNET platform together with the information of the networking.

Other configurations and operations of the intelligent trash can based on the internet of things and the multi-modal sensing technology and the using method thereof according to the embodiment of the invention are known to those skilled in the art and will not be described in detail herein.

In the description herein, references to the description of the terms "embodiment," "example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. Intelligent garbage bin based on thing networking and multimode sensing technology, its characterized in that: the method comprises the following steps:

an inner barrel for containing garbage;

the outer shell is sleeved on the periphery of the inner barrel;

the control core is arranged on the barrel wall of the shell and used for controlling the work of the modules;

the Internet of things module is used for connecting the Internet of things platform and the control core and providing a communication channel between the embedded system and the Internet of things platform, the embedded system is used for finishing data interaction with the cloud server through an API (application program interface) provided by the Internet of things platform, and the Internet of things platform issues data reading and writing instructions through corresponding API interfaces;

the weighing module is electrically connected with the control core and the Internet of things module, is arranged at the bottom of the inner barrel and is used for monitoring the weight of the garbage in the inner barrel;

the distance measuring module is electrically connected with the control core and the Internet of things module, is arranged in the middle of the garbage can cover and is used for measuring the distance to the inside of the garbage can so as to monitor the garbage volume in the garbage can;

the printer is electrically connected with the control core and the Internet of things module and used for printing a receipt for putting garbage into a user and cleaning the garbage by a cleaner;

the fingerprint identification module is electrically connected with the control core and the Internet of things module, is arranged on the outer wall of the shell and is used for comparing identity information of an operator during uncovering;

the automatic cover opening module is electrically connected with the control core and the Internet of things module, is arranged at a connecting shaft between the shell and the garbage can cover and is used for automatically opening and closing the garbage can cover according to the control of the control core;

the touch display screen module is electrically connected with the control core and the Internet of things module, and is used for displaying the real-time state and the detected physical quantity of the embedded system and providing the human-computer interaction functions of video playing, two-dimension code display and touch control.

2. The intelligent trash can based on the internet of things and the multi-modal sensing technology as claimed in claim 1, wherein: the weighing module is a weighing support provided with a strain type pressure sensor, the weighing support is matched with a 24-bit AD conversion module HX711 chip to realize the measurement of the weight of the garbage, the weighing support is arranged at the bottom of the inner side of the shell, the inner barrel is placed on the weighing support, and the weight of the inner barrel completely acts on the weighing support;

the strain type pressure sensor comprises four strain gauges which are arranged in an array mode, wherein two strain gauges are deformed under compression to reduce the resistance value, and the other two strain gauges are deformed under tension to increase the resistance value; the four strain gauges form a full-bridge circuit on the circuit connection, excitation voltage is input to one diagonal node, a corresponding voltage value is output to the other diagonal node, and the voltage value is in direct proportion to the bearing pressure of the bracket;

the HX711 chip is connected with the full bridge circuit in the weighing bracket by four leads, and each lead is connected to a node of the full bridge circuit; two wires apply voltage excitation; two output measurement effective voltage values are collected by an HX711 chip and are subjected to analog-to-digital conversion;

the HX711 chip is connected with the main control chip of the control core through two signal lines which comprise a synchronous clock line PD _ SCK and a data line DOUT, the two signal lines are connected to any two independent digital IO pins on the main control chip, and the HX711 chip is communicated with the main control chip through a private digital protocol of the HX711 chip.

3. The intelligent trash can based on the internet of things and the multi-modal sensing technology as claimed in claim 1, wherein: the ranging module selects TOF10120 laser ranging module for use, and its measuring face is installed towards the bucket, adopts standard IIC agreement communication between ranging module and the main control chip of control core, and total 2 signal lines are connected between ranging module and the main control chip of control core, contain synchronous clock line SCL and data line SDA.

4. The intelligent trash can based on the internet of things and the multi-modal sensing technology as claimed in claim 1, wherein: the control core also comprises a lithium battery, a power supply circuit, an anti-reverse connection circuit, an anti-surge current circuit, a crystal oscillator circuit, a FALSH module and a button battery;

the lithium battery is a 7.4V rechargeable lithium battery and is used for providing electric energy for the control core;

the power supply circuit is based on a synchronous buck converter, and converts an input power supply into a voltage required by an embedded system with the power supply efficiency of more than 90%;

the reverse connection preventing circuit adopts a PMOS tube and is used for preventing the control core from being damaged due to the reverse connection misoperation of the battery;

the anti-surge circuit is based on a transient suppression diode (TVS) and is used for providing effective protection for potential electrostatic discharge risk;

the crystal oscillator circuit comprises a 25MHz system crystal oscillator and a 32.768kHz real-time clock crystal oscillator, and the 25MHz system crystal oscillator is used for providing a reference clock required by the work for the embedded system; the real-time clock crystal oscillator of 32.768kHz is used for storing the time information and the key data of the system when the power is down;

the button battery is used for providing electric energy for a real-time clock and key data storage when the embedded system is powered off or enters a low power consumption mode;

the FLASH module is used for storing a Chinese character library and providing a Chinese character display function for the touch display screen module.

5. The intelligent trash can based on the internet of things and the multi-modal sensing technology as claimed in claim 1, wherein: the lithium battery is connected to an ADC pin of the main control chip through a voltage division circuit and used for monitoring the electric quantity of the battery in real time.

6. The intelligent trash can based on the internet of things and the multi-modal sensing technology as claimed in claim 1, wherein: the shell is equipped with the electromagnetic shield cover, the electromagnetic shield cover encloses and covers control core and thing networking module, thing networking module's antenna stretch out to the outside of electromagnetic shield cover.

7. The intelligent trash can based on the internet of things and the multi-modal sensing technology as claimed in claim 1, wherein: each module is provided with an LED working state indicator lamp corresponding to the module, and when the module works normally, the LED working state indicator lamp corresponding to the module is lightened; when the module does not work, the LED working state indicator lamp is turned off.

8. Use method of intelligent garbage bin based on thing networking and multimode sensing technology, its characterized in that: the intelligent trash can based on the internet of things and the multi-modal sensing technology and applied to any one of claims 1 to 7, comprising the following steps:

s2, the embedded system actively configures an Internet of things module; firstly, carrying out power-on inspection to determine that the Internet of things module is successfully started; then, signal quality inspection is carried out to determine the attachment state of the PS domain of the module; then, subscribing objects and resources, and then logging in the module to the physical network platform; if the login cannot be successfully carried out within the specified time, the module is restarted by pulling down the reset pin, and then the S2 flow is executed until the module is successfully logged in;

s3, the embedded system sends a survival time updating command at intervals to update the survival time of the module, so as to ensure that the module is in a real-time online state;

s6, when the embedded system receives an approval instruction issued by the physical network platform, the control core controls the stepping motor of the automatic uncovering module to rotate forward to open the trash can cover; the embedded system measures the garbage characteristics in the current inner barrel through the weighing module and the distance measuring module, simultaneously uploads the weight of the medical waste, the volume information of the medical waste and the information of operators which are input at this time through the physical network platform, and calls a printer to print the weight of the medical waste, the volume of the medical waste and the information of the operators which are input at this time;

s8, the system repeats the steps S4-S8.

9. The use method of the intelligent trash can based on the internet of things and the multi-modal sensing technology according to claim 8, characterized in that: in step S7, before the touch display screen receives the closing operation, the method further includes the following steps:

judging the type of the input medical waste according to the mass/volume ratio of the input garbage;

if the type of the input garbage is judged to be consistent with the type of the medical waste collected by the garbage can, receiving closing operation by the touch display screen;

if the type of the input garbage is judged to be inconsistent with the type of the medical waste collected by the garbage can, a confirmation window is filled out by the touch display screen for an operator to confirm.

10. The use method of the trash can only based on the internet of things and the multi-modal sensing technology according to claim 8, characterized in that: in step S6, when the weighing module detects that the weight of the inner barrel exceeds the set threshold and/or the distance measurement module detects that the volume of the waste at present exceeds the set threshold, the embedded system sends a full barrel alarm to the internet of things platform, and the internet of things platform pushes the full barrel alarm to the corresponding mobile terminal of the operator.