CN108211277B - Intelligent ping-pong ball picking sharing system and using method thereof - Google Patents

Abstract

The invention provides an intelligent table tennis ball picking and sharing system which comprises a trolley, a machine vision detection device, a rolling type ball collecting device, a motor transmission device, an obstacle avoiding device, a myRIO central control system, a power supply and an obstacle avoiding device, wherein the machine vision detection device is arranged on the trolley; the machine vision detection device is used for collecting images and sending image information to the myRIO central control system; the rolling ball collecting device is used for collecting the small balls into the rolling ball collecting device and preventing the small balls from falling out; the motor transmission device is used for driving the trolley to move; the obstacle avoidance device is used for avoiding surrounding obstacles to provide guidance for turning the trolley; the table tennis sharing device is used for receiving the small balls collected by the trolley, sequencing the small balls and providing the small balls for a user to use; the myRIO central control system is responsible for controlling the whole sharing system; the invention can pick up some scattered table tennis balls with low gaps and table bottoms, saves labor cost, improves the utilization rate of the table tennis balls and realizes unmanned management of the table tennis room.

Description

A table tennis intelligent ball picking and sharing system and its use method

technical field

The invention relates to a ball picking system, in particular to a table tennis intelligent ball picking and sharing system and a method for using the same.

Background technique

With the gradual promotion and application of automation in various fields at this stage and the continuous increase in the cost of human use, the sharing economy is becoming more and more popular; now some table tennis venues have the characteristics of small venues and dense table tennis tables; if the ball is under the table, then There will be difficulties in bending over, and even more, it will affect other people's play; a sharing system that can intelligently pick up the ball is urgently needed to solve the above problems.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a table tennis ball that can quickly, accurately and reliably detect and collect table tennis balls, reduce the fatigue of manpower frequently bending over to pick up the ball, and put the collected table tennis balls into a sharing device to realize sharing. An intelligent ball picking and sharing system and a method of using the same.

For achieving the above object, technical scheme of the present invention is as follows:

A table tennis intelligent ball picking and sharing system, the sharing system includes:

a small car

A machine vision detection device installed on the trolley, the machine vision detection device is used to collect images and send the image information to the myRIO central control system;

A rolling ball collection device arranged on the trolley, the rolling ball collection device is used to collect the small balls and will not fall out;

A motor transmission device arranged on the trolley, the motor transmission device is used to drive the trolley to move;

An obstacle avoidance device installed on the car, the obstacle avoidance device is used to avoid the surrounding obstacles and provide guidance for the car to turn;

A table tennis ball sharing device for receiving the small balls collected by the trolley, sorting them, and making them available to users;

A myRIO central control system installed on the trolley, the myRIO central control system is responsible for controlling the entire sharing system;

a power supply.

In one embodiment of the present invention, the machine vision detection device includes a camera, the camera on the camera is used to collect image information of surrounding table tennis balls, the camera is connected to the myRIO central control system through USB, and the collected image information is sent to myRIO central control system for image processing and recognition.

In one embodiment of the present invention, the rolling ball collecting device is in the form of a drum, which includes a shaft and two rollers, and elastic ropes are arranged at equal intervals between the two rollers, so that the table tennis balls can be collected The device gravitationally enters the inside of the collector without falling out of the collector.

In an embodiment of the present invention, the motor transmission device includes two deceleration motors and two motor drive boards, the motor drive boards are used for driving the deceleration motor, and the deceleration motor executes the processed electric power sent from the motor drive board. signal to realize forward and reverse.

In one embodiment of the present invention, the obstacle avoidance device includes infrared sensors disposed on the left and right sides of the trolley and ultrasonic sensors at the front and rear of the trolley.

In an embodiment of the present invention, the table tennis sharing device includes:

A box, the box is used to store the shared table tennis;

1. A display screen and a card swiping port set on the box, the display screen is used to display the QR code for paying the rental ping pong and the advertisement;

A motor installed in the box, the end of the motor is equipped with a paddle, in order to prevent the table tennis balls put in at one time from blocking the ball storage pipeline too much, there is a motor at the mouth of the pipeline to drive the paddle;

A table tennis ball recycler, the table tennis ball recycler is used to pour the collected table tennis balls into the table tennis ball recycler, and the table tennis ball recycler can make the table tennis balls roll down into the ball storage pipe;

A ball storage pipe, the ball storage pipe is a bent plastic pipe with a slightly larger diameter than the table tennis ball, the upper part has a larger angle with the ground, and the lower part has a smaller angle with the ground, which is convenient for the table tennis balls to be sorted and released;

An electronic switch, the electronic switch is controlled by the single-chip microcomputer and has a communication with the upper computer. When the upper computer has a ball out signal, only one ball is released, so as to avoid all the balls pouring into the ball outlet and causing blockage;

a host computer;

A baffle, when the electronic switch is turned on to drop a ball, the baffle opens to release the ball, and when there is no signal, it blocks the table tennis ball from falling;

The box body is provided with a ball outlet, which is connected with the ball storage pipe.

In one embodiment of the present invention, the myRIO central control system is the computing core of the entire system, which is an embedded real-time system with onboard digital and analog ports, which can be programmed through labview; And the signal of the ultrasonic sensor is processed to make a corresponding response; moreover, the motor is controlled to make a steering action.

In an embodiment of the present invention, a steering gear is provided below the camera head of the camera, and the steering gear controls the elevation angle of the camera to collect table tennis image information at different angles.

In an embodiment of the present invention, a steering gear is provided below the ultrasonic sensor, and the steering gear controls the elevation angle of the ultrasonic sensor, controls different directions of the ultrasonic waves, and uses obstacles in different directions to judge.

A method of using a table tennis intelligent ball-picking and sharing system, the specific steps of the using method are as follows:

(1) After receiving the ball picking command through wireless communication, the system is initialized, and the myRIO central control system controls the camera's camera to rotate up and down, so that the camera is 90 degrees from the ground;

(2) The camera transmits the collected table tennis image information to the myRIO central control system, and the myRIO central control system processes the image information to obtain the position information of the table tennis ball in the picture;

(3) After obtaining the position information, the car adjusts itself according to the position information of the picture so that the front of the car is facing the table tennis ball;

(4) The obstacle avoidance module judges the surrounding environment, and rotates if there is an obstacle until there is no obstacle;

(5) move forward to the table tennis position, when the ball enters the rolling ball collection device, count and carry out the next picking process until the rolling ball collection device is full;

(6) Put the table tennis balls in the rolling ball collection device into the table tennis ball sharing device and wait for the user to use it.

In one embodiment of the present invention, the specific method for processing image information by the myRIO central control system is:

(1) Binarize the received picture information, remove the color of the table tennis ball, and retain other color information;

(2) Filter the binarized image to remove the small block area that affects the subsequent identification;

(3) Invert the binarized area, leaving the shape information of the table tennis ball;

(4) Find the circular information in the binarized image, and obtain the position information of the table tennis ball in the image.

In an embodiment of the present invention, the steps of using the table tennis sharing device are as follows:

(1) The motor starts to rotate for 1 minute, until the table tennis balls enter the ball storage pipe or the ball storage pipe is full;

(2) The user enters the information by swiping the card or the network;

(3) The single-chip microcomputer controls the electronic switch and the baffle to release a ping-pong ball;

(4) The user takes the ball at the ball outlet.

Through the above-mentioned technical scheme, the beneficial effects of the present invention are:

The present invention uses the intelligent camera and the internal processing of myRIO to calculate the deviation angle, and then sends a fine-tuning command to the motor, so that the ball and the car can obtain an appropriate relative position, so as to pick up the ball; in the process, if the ultrasonic sensor or infrared sensor detects If there is an obstacle, priority will be given to the obstacle avoidance command; with this car, human resources can be greatly saved; after the player has finished playing the ball, they just walk away smartly, and the car will automatically execute the ball picking program after receiving the ball picking command and collect the collected The table tennis balls are sent to the shared device for next use; the system has the characteristics of flexibility, lightness, small size, and sharing.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

Fig. 1 is the structural block diagram of the sharing system of the present invention;

2 is a schematic structural diagram of a sharing system of the present invention;

Fig. 3 is the internal structure diagram of the table tennis sharing device of the present invention;

Fig. 4 is the working flow chart of the sharing system of the present invention;

Corresponding part names represented by numbers and letters in the figure:

100, trolley 200, machine vision detection device 210, camera 300, rolling ball collection device 400, motor transmission device 410, deceleration motor 420, motor drive board 500, obstacle avoidance device 510, infrared sensor 520, ultrasonic sensor 600, ping pong Ball sharing device 610, box 620, display screen 630, card swipe port 640, motor 641, paddle 650, table tennis ball collector 660, ball storage pipe 670, electronic switch 680, baffle 690, ball outlet 700, myRIO center Control system 800, power supply 900, steering gear.

Detailed ways

In order to make it easy to understand the technical means, creation features, achieved goals and effects of the present invention, the present invention will be further described below with reference to the specific figures.

Referring to FIGS. 1 to 3 , the present invention discloses a table tennis intelligent ball picking and sharing system, including a trolley 100, a machine vision detection device 200 arranged on the trolley, and a rolling ball collection device 300 arranged on the trolley , the electric motor transmission device 400 arranged on the trolley, the obstacle avoidance device 500 arranged on the trolley, the table tennis sharing device 600, the myRIO central control system 700 and the power supply 800 arranged on the trolley.

The machine vision inspection device 200 is used to collect images and send the image information to the myRIO central control system; the rolling ball collection device 300 is used to collect the balls and will not fall out; the motor transmission device 400 is used to drive the trolley Move; the obstacle avoidance device 500 is used to avoid the surrounding obstacles and provide guidance for the car to turn; the table tennis sharing device 600 is used to receive the balls collected by the car, sort them, and use them for the user; myRIO central control system 700 Responsible for controlling the entire shared system.

The machine vision inspection device 200 includes a camera 210. The camera on the camera is used to collect image information of surrounding table tennis balls. The camera is connected to the myRIO central control system through USB, and the collected image information is sent to the myRIO central control system for image processing. identify.

The rolling ball collection device 300 is in the shape of a drum, which includes a shaft center and two rollers, and elastic ropes are arranged between the two rollers at a certain radian and equal intervals, so that the table tennis balls can enter the inside of the collection device by the gravity of the collection device, It will not fall out of the collection device; the rolling ball collection device 300 is a common table tennis collection device, which will not be described in detail here, as long as it can collect the detected table tennis balls.

The motor transmission device 400 includes two deceleration motors 410 and two motor drive boards 420. The motor drive boards are used to drive the deceleration motors, so as to be connected to the motor and to the myRIO central control system, so that the myRIO central control system can pass the I/O The O port controls the speed and direction of the motor, and receives the data sent by the motor encoder to precisely control the movement of the trolley, such as the steering angle; the forward and reverse rotation of the two geared motors can be used to control the forward and reverse rotation of the ball picking robot; The processed electrical signal from the motor drive board, such as forward and reverse rotation, sends the signal of the grating back to the motor drive board, so that it can be encoded and sent to the myRIO central control system.

The obstacle avoidance device 500 includes infrared sensors 510 arranged on the left and right sides of the trolley and ultrasonic sensors 520 at the front and rear of the trolley. The potentiometer on the sensor sets the inspection distance, and sends a signal to the myRIO central control system through the I/O port; the myRIO central control system judges whether there is an obstacle according to the received signal; the ultrasonic sensor 520 comes with a 32 chip and The LED digital tube displays the distance; through the three buttons, you can set what signal to send in what range, and connect with the myRIO central control system through the I/O port to cooperate with the lower steering gear 900 to detect whether there are obstacles in different directions.

The table tennis sharing device 600 includes a box body 610, a display screen 620 and a card swipe port 630 arranged on the box body 610, a motor 640 arranged in the box body, a table tennis ball recovery device 650, a ball storage pipe 660, an electronic switch 670, and a host computer and baffle 680.

The box body 610 is used to store shared table tennis. The box body 610 is provided with a ball outlet 690, which is connected to the ball storage pipe 660. The dropped table tennis balls are in the ball outlet 690, which is convenient for users to take the ball; the display screen 620 is used to display the QR code and advertisements for paying rental table tennis; the card swipe port 630 is used to pay table tennis rental fees and input information; the end of the motor 640 is equipped with a paddle 641, in order to prevent excessive blockage of table tennis balls placed at one time The ball storage pipeline has a motor to drive the paddle. During normal operation, when the trolley is fully loaded with balls and returns to the table tennis ball recycler, the host computer sends a signal to control the motor to drive the paddle to work, so as to solve the problem of too many balls blocking the ball storage pipeline. Problem; the table tennis ball recycler 650 is used to pour the collected table tennis balls into the table tennis ball recycler, and the table tennis ball recycler has a certain angle to make the table tennis balls roll into the ball storage pipe; the ball storage pipe 660 is a curved The folded plastic pipe with a slightly larger diameter than the table tennis ball has a larger angle between the upper part and the ground, and a smaller angle between the lower part and the ground, which is convenient for the sorting and ejection of the table tennis balls; the electronic switch 670 is controlled by the single-chip microcomputer and has a communication with the upper computer. When the upper computer has a ball out signal, only one ball is released, so as to avoid all the balls pouring into the ball outlet and causing blockage;

When the electronic switch is turned on to drop a ball, the baffle is opened to release the ball, and when there is no signal, the table tennis ball is blocked from falling.

myRIO central control system 700 is the computing core of the whole system. It is an embedded real-time system with on-board digital and analog ports, which can be programmed through labview; Corresponding response; furthermore, control the motor to make steering action.

A steering gear 900 is arranged below the camera of the camera 210, and the steering gear 900 controls the elevation angle of the camera to collect table tennis image information from different angles; a steering gear 900 is arranged below the ultrasonic sensor 520, and the steering gear 900 controls the elevation angle of the ultrasonic sensor 520 to control the ultrasonic wave. Different directions have been used to judge obstacles in different directions.

The power supply 800 is a 12V rechargeable lithium battery. Since the input voltage range of the myRIO central control system allows 12V input, the motor driver board needs 12V voltage and 5V voltage output, so the power supply is connected to the myRIO central control system and the motor driver board respectively, and then Use the 5V power output from the myRIO central control system to power 5V devices such as servos, infrared sensors, etc.

The working principle of the sharing system of the present invention is as follows:

First, the camera of the camera roughly judges whether there is a table tennis ball by changing the elevation angle to 90 degrees perpendicular to the ground. If not, change the positive direction of the car to judge. If there is no direction in all directions, the car returns to the designated position.

If a ping-pong ball is detected, move the ball picking robot to the vicinity of the ping-pong ball and adjust the camera to 60 degrees relative to the ground for further detection, and then judge again whether there is a real ball. When there is indeed a table tennis ball, fine-tune the angle of the ball picking robot, so that the table tennis ball is in a position that can pass under the ball picking robot, so that the collector can collect the table tennis balls; when the ball picking action is completed, re-enter the first step to check whether There are balls.

In this process, obstacle avoidance is always performed. No matter which of the above actions is being performed, the program will be suspended first when an obstacle is detected. Until the obstacle avoidance is completed and there are no obstacles, the normal ball picking process will be performed.

The specific use method of the table tennis intelligent ball picking and sharing system of the present invention is as follows:

The situation of the car before use is as follows: the normal forward direction of the car is to use the camera as the front of the car, the ping-pong ball collector is the rear of the car, and the chassis height of the car is greater than the diameter of a ping-pong ball. The ping pong ball rolled in.

(1) Initialize the system. When the trolley is turned on, the camera's camera elevation angle is 90 degrees from the ground, and the image is collected, and the image is transmitted to the myRIO central control system;

(2) The myRIO central control system identifies whether there is a table tennis ball in the image. At this time, due to the large detection range, false detection may occur;

(3) If there is no, adjust the direction of the front of the body and return to (2) detection again. If there is no direction in all directions, the program will stop. If there is a ball, adjust the direction of the robot to approach the table tennis ball;

(4) Adjust the camera's elevation angle to 60 degrees from the ground;

(5) Perform image detection again to determine whether there is a table tennis ball;

(6) if not, then go back to step (3), if there is, then proceed to the next step;

(7) Fine-tune the direction of the robot so that the ball can pass under the small body;

(8) The trolley moves forward, passes the table tennis ball collector at the rear of the trolley, and collects the table tennis balls into the table tennis ball collector;

(9) return to step (3);

(10) No matter which step is executed, it will always judge whether there is an obstacle;

(11) Implement obstacle avoidance if there are obstacles;

(12) If any one of the infrared sensor and the ultrasonic sensor detects an obstacle, it is considered that there is an obstacle;

(13) If only the infrared sensor has obstacles, the small angle deviates from the obstacle side;

(14) If the ultrasonic sensor detects an obstacle, that is, there is an obstacle in front of it, the steering gear under the ultrasonic sensor rotates 90 degrees left and right to determine whether there is an obstacle;

(15) The trolley turns to the direction without obstacles;

(16) If there is no obstacle, resume the execution of the ball picking procedure;

(17) If the trolley after counting the full balls returns to the designated position and waits to recover the table tennis balls;

(18) The recovered balls are placed in the shared device and are waiting for the user to use.

The specific method of the myRIO central control system to identify the image is as follows:

(1) Binarize the received picture information, remove the color of the table tennis ball, and retain other color information;

(2) Filter the binarized image to remove the small block area that affects the subsequent identification;

(3) Invert the binarized area, leaving the shape information of the table tennis ball;

(4) Find the circular information in the binarized image, and obtain the position information of the table tennis ball in the image.

The specific working steps of the sharing system are as follows:

(1) Send a signal to the trolley to load the picked up ball into the table tennis ball recovery device;

(2) The motor starts to rotate for 1 minute, until the table tennis balls enter the ball storage pipe or the ball storage pipe is full;

(3) The user enters the information by swiping the card or the network,

(4) The single-chip microcomputer controls the electronic valve and the baffle to release a ping-pong ball

(5) The user takes the ball at the ball outlet.

The specific operation process of using the system of the present invention to detect and collect pellets is as follows:

Step 1), install the battery, the robot automatically starts, and the robot can automatically start to search and collect table tennis balls in the field;

Step 2), if the robot fails, you can press the button on the myRIO to stop it urgently;

Step 3), end.

The basic principles and main features of the present invention and the advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (8)

1. a table tennis intelligent ball picking sharing system, is characterized in that, described sharing system comprises: a small car A machine vision detection device installed on the trolley, the machine vision detection device is used to collect images and send the image information to the myRIO central control system; A rolling ball collection device arranged on the trolley, the rolling ball collection device is used to collect the small balls and will not fall out; An electric motor transmission device arranged on the trolley, the electric motor transmission device is used to drive the trolley to move; An obstacle avoidance device installed on the car, the obstacle avoidance device is used to avoid the surrounding obstacles and provide guidance for the car to turn; The obstacle avoidance device includes infrared sensors arranged on the left and right sides of the trolley and ultrasonic sensors at the front and rear of the trolley, and the infrared sensors and ultrasonic sensors are respectively used for the left and right direction barriers and the front and rear direction barriers; The infrared sensor can set the inspection distance through the potentiometer on the infrared sensor, and send a signal to the myRIO central control system through the I/O port; the myRIO central control system judges whether there is an obstacle according to the received signal; With a 32-inch chip and LED digital tube to display the distance; through the three buttons, you can set what signal to send in what range, connect with the myRIO central control system through the I/O port, and cooperate with the following servos to detect whether there are obstacles in different directions. ; A table tennis ball sharing device for receiving the small balls collected by the trolley, sorting them, and making them available to users; Table tennis sharing equipment includes: A box, the box is used to store the shared table tennis; 1. A display screen and a card swipe port set on the box, the display screen is used to display the QR code and advertisements for paying the rental ping pong; A motor installed in the box, the end of the motor is equipped with a paddle, in order to prevent the table tennis balls put in at one time from blocking the ball storage pipeline too much, there is a motor at the mouth of the pipeline to drive the paddle; A table tennis ball recycler, the table tennis ball recycler is used to pour the collected table tennis balls into the table tennis ball recycler, and the table tennis ball recycler can make the table tennis balls roll down into the ball storage pipe; A ball storage pipe, the ball storage pipe is a bent plastic pipe with a slightly larger diameter than the table tennis ball, the upper part has a larger angle with the ground, and the lower part has a smaller angle with the ground, which is convenient for the table tennis balls to be sorted and released; An electronic switch, the electronic switch is controlled by the single-chip microcomputer and has a communication with the upper computer. When the upper computer has a ball out signal, only one ball is released, so as to avoid all the balls pouring into the ball outlet and causing blockage; a host computer; A baffle, when the electronic switch is turned on to drop a ball, the baffle opens to release the ball, and when there is no signal, it blocks the table tennis ball from falling; There is a ball outlet on the box, and the ball outlet is connected with the ball storage pipe; A myRIO central control system installed on the trolley, the myRIO central control system is responsible for controlling the entire sharing system; a power supply; The machine vision detection device includes a camera, and a steering gear is arranged below the camera head of the camera, and the steering gear controls the elevation angle of the camera to collect table tennis image information from different angles; A steering gear is arranged below the ultrasonic sensor, and the steering gear controls the elevation angle of the ultrasonic sensor, controls the different directions of the ultrasonic waves, and uses obstacles in different directions to judge. 2. a kind of table tennis intelligent ball picking and sharing system according to claim 1 is characterized in that, the camera on the camera is used to collect the surrounding table tennis image information, and the camera is connected to the myRIO central control system through USB, and will collect the The image information is sent to the myRIO central control system for image processing and identification. 3. A table tennis intelligent ball picking and sharing system according to claim 1, wherein the rolling ball collecting device is in the shape of a roller, which comprises an axis and two rollers, and between the two rollers Elastic ropes are arranged at equal intervals, so that the table tennis balls can enter the inside of the collecting device by the gravity of the collecting device, and will not fall out of the collecting device. 4. A table tennis intelligent ball picking and sharing system according to claim 1, wherein the motor transmission device comprises two deceleration motors and two motor drive plates, and the motor drive plates are used for the drive of the deceleration motor, The geared motor executes the processed electrical signal sent from the motor drive board to realize forward and reverse rotation. 5. a kind of table tennis intelligent ball picking sharing system according to claim 1 is characterized in that, described myRIO central control system is the computing core of the whole system, it is an embedded real-time system, onboard digital and analog ports , can be programmed through labview; will receive signals from cameras, infrared sensors and ultrasonic sensors for processing, and make corresponding responses; moreover, control the motor to make steering actions. 6. the use method of the table tennis intelligent ball picking sharing system in any one of claim 1 to 5, is characterized in that, the concrete steps of described use method are as follows: (1) After receiving the ball picking instruction through wireless communication, the system is initialized, and the myRIO central control system controls the camera's camera to rotate up and down, so that the camera is 90 degrees from the ground; (2) The camera transmits the collected table tennis image information to the myRIO central control system, and the myRIO central control system processes the image information to obtain the position information of the table tennis ball in the picture; (3) After obtaining the position information, the car adjusts itself according to the position information of the picture so that the front of the car is facing the table tennis ball; (4) The obstacle avoidance module judges the surrounding environment, and rotates if there is an obstacle until there is no obstacle; (5) move forward to the table tennis position, when the ball enters the rolling ball collection device, count and carry out the next picking process until the rolling ball collection device is full; (6) Put the table tennis balls in the rolling ball collection device into the table tennis ball sharing device and wait for the user to use it. 7. the using method of a kind of table tennis intelligent ball picking sharing system according to claim 6, is characterized in that, the concrete method that described myRIO central control system is processed to image information is: (1) Binarize the received picture information, remove the color of the table tennis ball, and retain other color information; (2) Filter the binarized image to remove the small block area that affects the subsequent identification; (3) Invert the binarized area, leaving the shape information of the table tennis ball; (4) Find the circular information in the binarized image, and obtain the position information of the table tennis ball in the image. 8. The using method of a table tennis intelligent ball picking and sharing system according to claim 6, wherein the steps of using the table tennis ball sharing device are as follows: (1) The motor starts to rotate for 1 minute, until the table tennis balls enter the ball storage pipe or the ball storage pipe is full; (2) The user enters the information by swiping the card or the network; (3) The single-chip microcomputer controls the electronic switch and the baffle to release a ping-pong ball; (4) The user takes the ball from the ball outlet.

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