“This system is composed of two subsystems, the customer call service system and the dining table management system. The transmitter of the customer call service system is placed on the dining table, and the customer presses the transmitter button, and the receiver equipped with the waiter will receive the call information. The transmitter of the dining table management system is carried on the waiter. When there is a customer at the dining table, press the corresponding key (press the key twice when the customer is occupied at the beginning, and press it only once at the beginning of the idle time), and the service desk will start timing after receiving the information , The customer presses the corresponding button after leaving, so that the general service desk knows the usage of the table.
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Authors: Liu Renping, Cheng Tao, Xie Tiejun, Liu Yan
When dining in a restaurant, I often encounter the following problems. First, waiters provide services to several tables at the same time. They often go to the kitchen to send customers to order menus, go to the cashier to check out the customers, etc. and stay away from the table that provides services. At this time, it is very inconvenient for customers to call the waiter. Second, when customers dine in private rooms, they often talk about content that is not convenient for others to know, so they have to let the waiter avoid it from time to time, and sometimes call the waiter manually, which is very inconvenient. Third, if the restaurant is large, it is difficult for the service desk to grasp table usage information in real time, which will directly affect the arrangements for customers to eat. The wireless call service system of this restaurant solves the above problems.
This system is composed of two subsystems, the customer call service system and the dining table management system. The transmitter of the customer call service system is placed on the dining table, and the customer presses the transmitter button, and the receiver equipped with the waiter will receive the call information. The transmitter of the dining table management system is carried on the waiter. When there is a customer at the dining table, press the corresponding key (press the key twice when the customer is occupied at the beginning, and press it only once at the beginning of the idle time), and the service desk will start timing after receiving the information , The customer presses the corresponding button after leaving, so that the general service desk knows the usage of the table.
1 System principle
Each subsystem is composed of two parts: information transmission and information reception. The principle of the transmitter is shown in Figure 1, and the principle of the receiver is shown in Figure 2.
The encoding and decoding of the customer call service system is realized by the encoding and decoding chip, and the encoding and decoding of the dining table management system is realized by the single-chip microcomputer. The information processing of the customer call service system is realized by sound and light Display of the call information. The dining table management system can display the idle or occupied time of each dining table in real time.
2 Customer call service system
The principle of the transmitter circuit is shown in Figure 3, and the principle of the receiver is shown in Figure 4. The transmitter uses VD5026 encoder for pulse digital modulation.
It has 4-bit address coding and 4-bit data input. The transmitter buttons A, B, C, and D correspond to the D0, D1, D2, and D3 data output terminals of the decoder VC5027 on the receiver. A, B, C, and D represent the buttons on the 4 dining tables. When the A key is pressed, the T631 receiving head receives the coded signal, after internal demodulation, amplifying and shaping, it is output from the OUT terminal and decoded by the VD5027. When the encoding instruction information is consistent with the data set by VD5027, the decoding valid terminal VT and the corresponding data output terminal D0 both output high level, the transistor V1 is turned on, the light is on, and the VT drives the music module to alarm, and the D0 latch remains high. Level, VT is the pulse level to choose the trigger music module.
Because VD5026 has 8-bit 4-state address encoding, the encoding end can be connected to three states of high level “1”, low level “0” or “open circuit”. Therefore, a maximum of 38=6561 non-repeated codes can be generated, and only two states of “1” and “0” are selected for coding. There are 28=256 codes in total, and each code can manage 4 dining tables. Therefore, the maximum design capacity of this system is to provide call service for 1024 tables, which is sufficient to meet the actual needs of the restaurant.
3 Dining table management system
The operating frequency of the above-mentioned T630 and T631 is 265MHz. In order to prevent interference, the dining table management system chooses another transceiver module, the transmitter module model is NT-01TA, the receiver module model is NT-R01F, and the working frequency is 315MHz, which avoids mutual interference between the two systems. At the same time, this module It is more suitable for connection with single chip microcomputer.
The encoding chip has 4 data bits. Even if a 4-16 decoder is used for the same encoding, there can only be 16 kinds of encoding at most. Using this method to transmit table management information can only process up to 16 tables of table information, which cannot meet actual needs. Therefore, encoding and decoding chips cannot be used, but software encoding and decoding solutions are used. The transmitter uses AT89C2051 single-chip microcomputer for encoding, and the receiver uses AT89C51 single-chip microcomputer for decoding, so that there are no restrictions on encoding and decoding, and the number of encoding bits can be determined according to needs. Also, unlike encoding and decoding chips, data can only be received when the address encoding is consistent. code. In order to be consistent with the customer call system, this system also uses 4-bit data coding, and the waiter code uses 8-bit coding as needed, so that the system can process up to 1024 table information.
The principle of the transmitter equipped by the table attendant is shown in Figure 5, and the principle of the receiver of the service center is shown in Figure 6. The transmitter software flow chart is shown in Figure 7.
The receiver software is composed of a main program and a data receiving interrupt program. The main program flow chart is shown in Figure 8, and the data receiving interrupt program flow chart is shown in Figure 9. The data rate sent by the customer call service system from the dining table to the waiter is 1.2Kbps. The sending data has 8 bits of address encoding and 4 bits of data encoding, a total of 12 bits, and the sending time takes about 10ms. Therefore, as long as the special event of several tables calling at the same time within 10ms does not occur, the information can be reliably transmitted. It can be seen that the possibility of data transmission conflict is almost zero. Even if such a small probability event occurs, it is enough to call again. The data transmission conflict situation of the table management system is similar, and it is also a small probability event.
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