Restaurant wireless call service system design

    Abstract: This paper analyzes the current restaurant management system and designs a fast and timely wireless calling system. In addition to solving the problem of timely service, this system also allows the restaurant service desk to know the usage of each table, thereby providing a reliable basis for the scientific management of tables.

    Keywords: microcontroller encoder decoder

When dining in restaurants, we often encounter the following problems. First, waiters provide services to several tables at the same time. They often go to the kitchen to take customers' orders, go to the cashier to pay for customers, etc. They are far away from the serving tables. At this time, it is very inconvenient for customers to call the waiters. Secondly, when dining in a private room, customers often talk about things that are not convenient for others to know, so they have to ask the waiter to avoid the conversation sometimes, and sometimes call the waiter manually, which is very inconvenient. Third, if the restaurant is large, it will be difficult for the front desk to grasp table usage information in real time, which will directly affect the arrangement of customer dining. This meal wireless call service system solves the above problems.

This system consists of two subsystems: customer call service system and table management system. The transmitter of the customer call service system is placed on the dining table. When the customer presses the transmitter button, the receiver equipped on the waiter will receive the call information. The transmitter of the table management system is carried on the waiter. When there is a customer at the table, press the corresponding key (press the key twice in succession when it is occupied by customers, and press it only once when it becomes idle). The service desk will start timing after receiving the information. , the customer leaves and then presses the corresponding button, so that the front desk will know the usage of the table.

1 System principle

Each subsystem consists of two parts: information transmitting and information receiving. The transmitter principle is shown in Figure 1, and the receiver principle is shown in Figure 2. The encoding and decoding of the customer call service system is realized by encoding and decoding chips, and the encoding and decoding of the dining table management system is realized by the microcontroller. The information processing of the customer call service system is realized by displaying the call information through sound and light. The table management system can display the idle or occupied time of each table in real time.

2 Customer call service system

The transmitter circuit principle is shown in Figure 3, and the receiver circuit principle is shown in Figure 4. The transmitter uses VD5026 encoder for pulse digital modulation. It has 8-bit 4-state address encoding and has 4-bit data input. The transmitter buttons A, B, C, and D respectively correspond to the D0, D1, D2, and D3 data output terminals of the decoder VD5027 on the receiver. A, B, C, and D respectively represent the buttons on the four dining tables. When the A button is pressed, after the T631 receiving head receives the encoded signal, it is internally demodulated, amplified and shaped, then 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 effective terminal VT and the corresponding data output terminal D0 both output high level, the transistor V1 is turned on, the light is on, VT drives the music module to alarm, and the D0 latch remains high Level, VT is the pulse level (triggered music module needs to be selected).

Since VD5026 has an 8-bit 4-state address encoding, the encoding terminal can be connected to three states: high level "1", low level "0" or "open circuit". Therefore, up to 3 8 = 6561 unique codes can be generated.Only two states, "1" and "0", are selected for coding. There are a total of 2 8 = 256 codes, and each code can manage 4 dining tables. Therefore, the maximum design capacity of this system is to provide call services for 1024 dining tables, which is enough to meet the actual needs of the restaurant.

3 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 chose another transceiver module. The transmitter module model is NT-01TA, the receiver module model is NT-R01F, and the working frequency is 315MHz. This avoids mutual interference between the two systems. At the same time, this module More suitable for connecting with microcontroller.

The encoding chip has 4 data bits. Even if a 4-16 decoder is used for the same encoding, there can only be 16 encodings at most. Using this method to transmit table management information can only be regarded as 16 table information at most, 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 microcontroller for encoding, and the receiver uses AT89C51 microcontroller for decoding. In this way, there will be no restrictions on encoding and decoding. The number of encoding digits can be determined as needed, and unlike encoding and decoding chips, data can only be received when the address encoding is consistent. code. In order to make the customer call system consistent, this system also uses 4-digit data coding, and the waiter code uses 8-bit coding as needed. In this way, this system can handle up to 1024 table information.

The principle of the transmitter equipped with the table waiter is shown in Figure 5, and the principle of the receiver of the service station is shown in Figure 6.

The transmitter software flow chart is shown in Figure 7. The receiver software consists of the main program and the data reception interrupt program. The flow chart of the main program is shown in Figure 8, and the flow chart of the data reception interrupt program is shown in Figure 9.

The data rate sent by the customer call service system from the table to the waiter is 1.2Kbps. The sent data has 8-bit address encoding and 4-bit data encoding, a total of 12 bits, and the sending time takes about 10ms. Therefore, as long as there is no special event such as several tables calling at the same time within 10ms, information can be transmitted reliably. It can be seen that the possibility of data transmission conflict is almost zero. Even if such a small probability event occurs, just call again. The situation of data transmission conflicts in the dining table management system is similar, and it is also a small probability event.