CN101769884A - Indicator for forecasting shelf life of cold fresh pork - Google Patents

Abstract

The invention relates to an indicator for predicting the shelf life of chilled fresh pork. The indicator belongs to the technical field of detecting the quality of pork by collecting the temperature. During the circulation process of pork from production to sale, the indicator collects the temperature of pork in real time and predicts its shelf life. The indicator is small in size and easy to use. It can be directly attached to the surface of chilled pork, and its temperature, shelf life, and system time can be updated and displayed in real time. The indicator uses a high-precision temperature sensor DS18B20 to collect the surface temperature of chilled fresh pork, and transmits the temperature value to the microcontroller MSP430F1XX through the data line DQ, and then the controller predicts its real-time shelf life according to the temperature-based TTT theory, and then the LCD screen LM6059BCW displays the temperature value and shelf life value, as well as system time and food name. The system time, real-time temperature and shelf life are all stored in the extended memory card every hour, and these data are transmitted to the computer through the serial port of the indicator when the user needs it. The indicator has high prediction accuracy, low power consumption, multiple functions, and easy operation, and efficiently solves the difficult problem of shelf life prediction in the circulation process of chilled fresh pork.

Description

Chilled Pork Shelf Life Prediction Indicator

technical field

The invention is an indicator which uses a temperature sensor attached to the surface of chilled fresh pork to predict its shelf life by calling an algorithm in a rule library in real time, and uses a display screen to display various data.

Background technique

At present, consumers' consumption orientation of pork is undergoing major changes, and their demand for "safe meat" has greatly increased. Only safer, more hygienic and more nutritious chilled fresh pork can meet their consumption needs. Guided by such demands, food safety and traceability will be the focus of consumers' attention. But so far, there is no electronic chilled fresh pork quality detection device to occur yet.

The existing shelf life prediction device for dairy products is designed based on the principle of an embedded system, which has many disadvantages, such as: low prediction accuracy, power supply, high power consumption, large volume and inconvenient use, and does not have historical temperature And the query function of shelf life (that is: the traceability of food cannot be guaranteed), and the real-time alarm cannot be issued when the quality of dairy products is at a critical point, etc., have not been applied in real life. Therefore, there is an urgent need for a shelf-life prediction device with high prediction accuracy, small size, ultra-low power consumption, traceable historical data, and convenient use at any stage of chilled pork.

Contents of the invention

The purpose of inventing the shelf life prediction device for chilled fresh pork is to provide a real-time quality detection instrument for chilled pork, to solve the problem that the quality prediction of chilled fresh pork is difficult to change in real time following environmental changes, and to support the retrospective function of its historical quality change data .

In order to achieve the above functions, the indicator collects the real-time temperature of chilled fresh pork at regular intervals through the temperature sensor DS18B20, and transmits the temperature value to the microprocessor MSP430F1XX through the bidirectional data transmission line DQ of the temperature sensor, and the microprocessor selects according to the temperature value. A rule in the shelf life prediction rule base predicts the real-time remaining shelf life of chilled pork; then, the LCD LM6059BCW updates the temperature, shelf life and system time in real time. When the real-time temperature of chilled pork is higher than the temperature threshold, the temperature value will flash on the LCD screen to remind the user, and the alarm will be given every 30 minutes until the temperature is lower than the temperature threshold; when the real-time shelf life of chilled pork is lower than the shelf life When the threshold is reached, the buzzer will alarm to remind the user, and the alarm will be issued every 30 minutes until the chilled pork is sold or the system prediction ends. Finally, the automatic and intelligent detection of chilled pork quality and environmental conditions has been realized.

The software used in this shelf life prediction indicator mainly includes main program, temperature acquisition subroutine, shelf life calculation subroutine, temperature alarm subroutine, shelf life alarm subroutine, data storage subroutine, liquid crystal display subroutine, system time running subroutine program, communication subroutine with host computer, etc.

The indicator includes ultra-low power consumption microprocessor chip MSP430F1XX and its peripheral circuit, temperature sensor DS18B20 module, single key button module, shelf life alarm module, LCD screen LM6059BCW display module, data storage AT24C64 module, calendar clock chip DS1302 Modules and communication modules based on serial port RS232, the block diagram of each module and the connection circuit and electrical signal circuit between each chip, see Figure 1 and Figure 2. Among them, the microprocessor MSP430F1XX receives the temperature value collected by the temperature sensor DS18B20, selects a certain rule in the rule base to calculate the shelf life according to the temperature value, and then sends the name (fresh pork), temperature, shelf life, and system time to the LCD screen LM6059BCW display. Among them, the system time is provided by the calendar clock chip DS1302, and the format of the time displayed on the LCD screen is "month, month, day, hour: minute and minute". Each updated real-time temperature, real-time shelf life, and system time are transmitted to the data storage chip AT24C64 for storage by means of I2C communication. When the user needs to trace historical data, these data can be called out on the LCD of this indicator. It can be displayed on the screen or uploaded to the computer for viewing in text form. The advantages of high prediction accuracy, small size, ultra-low power consumption, traceable historical data, and easy use at any stage of chilled pork provide an efficient and convenient tool for real-time monitoring of the quality of chilled pork, which greatly improves the quality of chilled pork. The degree of quality assurance and utilization efficiency of pork.

Description of drawings

Fig. 1 is the composition module schematic diagram of the present invention

Fig. 2 is the hardware design schematic diagram of the present invention

Fig. 3 is a schematic diagram of system functions of the present invention

Fig. 4 is the overall flow chart of the system of the present invention

Detailed ways

The following content is a further detailed description of the shelf life prediction indicator of the present invention in conjunction with the accompanying drawings.

The shelf life prediction indicator of chilled fresh pork, the schematic diagram of its components includes an ultra-low power consumption microprocessor module (MSP430F1XX), a temperature sensor module (DS18B20), a single-key button module (reset, menu, jump, ok, <, >) , buzzer alarm module (shelf life alarm), liquid crystal display module (LM6059BCW), data storage module (AT24V64), calendar clock module (DS1302), serial communication module (RS232 communication protocol) and power processing module (5V Li battery) etc.; Among them, the temperature alarm function is all realized by software.

First, the temperature sensor module collects the real-time temperature of the surface of chilled fresh pork at a preset time point, and the microprocessor selects a rule in the shelf-life prediction rule base according to the temperature value, and adopts the corresponding first-order kinetic reaction formula and Arrhenius The equation calculates the real-time shelf life of chilled pork; a microprocessor then transmits this data to an LCD display. When the temperature value or shelf life value exceeds the threshold, the indicator will alarm; the system preset temperature threshold is 20°C, and the shelf life threshold is 1.5 days, and the user can modify the temperature threshold and shelf life threshold as needed. Finally, when the chilled fresh pork is sold or the shelf life is zero, the indicator ends the shelf life prediction process. The real-time temperature, shelf life, and system time of the indicator are transmitted to the data storage chip AT24C64 according to the I2C communication protocol for storage; The data is transmitted to the computer according to the communication method of the RS232 serial port protocol, so that the quality change process of chilled fresh pork can be traced.

The system has large storage capacity (60KB FLASH, 64Kb data storage), strong computing power, modularized and intelligent software, has a unified and complete external debugging JTAG interface and a common standard RS232 serial communication port, and the chip MSP430F1XX has reserved many ports. Therefore, the indicator has good expansibility and high flexibility. The hardware circuit design of the device includes a microprocessor based on MSP430F1XX, a temperature sensor, a liquid crystal display, a data storage chip, a calendar clock chip, a single-key button, a buzzer, and a serial communication circuit based on RS232, which constitute the connection circuit and electrical circuit of each chip. Embedded hardware platform for signal connection circuits. The software of this indicator adopts modular design, and each physical device has corresponding subroutines to complete their respective functions. Real-time interface, temperature query interface, data transmission interface, initial shelf life interface, initial system time interface, change default threshold interface, data transmission process interface, data transmission end interface, inquiry prediction end interface, prediction end interface, etc. 13 interfaces display, the 6 buttons that cooperate with this indicator can realize the quality monitoring of chilled fresh pork simply and efficiently. Among them, the "reset" button can realize the reset operation of the indicator and make the indicator run again; when the indicator is running on any of the 13 interfaces, press the "menu" button to return the interface to the system function menu interface .

The main technology that device of the present invention adopts is as follows:

1. Embedded technology

The design of the whole indicator is based on the theory of embedded technology. The advantage of the embedded system is that it can collect a large number of signals, the processing speed is fast, and the real-time performance is good; the main controller of this indicator adopts the ultra-low power consumption microprocessor MSP430F1XX produced by TI Company, which has 60KB FLASH and 2KB RAM. FLASH is mainly used to store system software, temperature acquisition software, shelf life calculation software, etc. RAM is mainly used to store intermediate variables during the indicator’s operation. The main frequency of MSP430F1XX can reach 8Mhz, which guarantees its fast data processing ability, and the existence of hardware multiplier enables the system to get the real-time shelf life of white shrimp faster; its USART supports UART function and SPI function, this indicator The UART method is used to realize the fast transmission of system data; the timer realizes the timing function of the temperature collection time and the shelf life calculation time. When the timing interval is up, the indicator is triggered to collect the temperature and calculate the shelf life.

2. I2C technology

The data transmission between the microprocessor MSP430F1XX and the data memory AT24C64 adopts I2C communication technology. The I2C serial bus technology generally has two signal lines, one is a bidirectional data line SDA, and the other is a clock line SCL. The serial data line SDA interface of the data storage chip AT24C64 is bidirectional, the output circuit is used to send data to the MSP430F1XX bus, and the input circuit is used to receive data on the MSP430F1XX bus. The serial clock line SCL is also bidirectional. As the Master MSP430F1XX that controls the bus data transmission, on the one hand, it needs to send the clock signal through the SCL output circuit, and on the other hand, it also needs to detect the SCL level on the bus; as the Slave AT24C64 that accepts the host command , to operate on the SCL signal on the bus or receive the signal on SDA. The storage and query of the real-time data of this indicator is realized by Master MSP430F1XX sending commands and data through the cooperation of SCL and SDA to control Slave AT24C64.

3. RS232 technology

This indicator is stored in the data stored in the chip AT24C64 by means of I2C communication. When the user needs it, it can be transmitted to the host computer through RS232 serial port communication. RS232 is a relatively mature serial data transmission protocol developed so far. The signal is stable during the data transmission process. It does not need an external power supply. It only needs pins 2 and 3 to realize data transmission with the USART0 of the microprocessor MSP430F1XX, so it was selected Make the communication protocol between the indicator and the computer. The UTXD0 and URXD0 of the system microprocessor MSP430F1XX support the UART data transmission mode, and are connected to the RS232 serial port No. 2 and No. 3 pins respectively to realize data transmission. The indicator customizes the data packet and data transmission of RS232 process.

Claims (4)

1. the present invention is a kind of indicator for forecasting shelf life of cold fresh pork based on super low-power consumption embedded microprocessor MSP430F1XX, mainly by microprocessor MSP430F1XX, temperature sensor DS1302, LCD LM6059BCW, calendar clock chip DS1302, RS232 serial ports, 64Kb pin-saving chip AT24C64, buzzer alarm circuit, 6 separate single keys (that is: reset, menu, redirect, affirmation,＜) connecting circuit of peripheral circuit such as circuit and each chip chamber forms.

2. based on the indicator for forecasting shelf life of cold fresh pork of super low-power consumption embedded microprocessor MSP430F1XX, its 60KBFLASH that carries is mainly used in the storage system code, as: master routine, temperature acquisition subroutine, shelf life counting subroutine, temperature alarming subroutine, shelf life warning subroutine, data storage subroutine, liquid crystal display subroutine, system time runtime subroutine, with host computer communicator program etc.; Intermediate data when the 2KB RAM that it carries is mainly used to the storage system operation, the process data during as the calculating shelf life etc.Wherein, communicating by letter with host computer is by the RS232 serial ports, and each data packets for transmission length is 4 bytes, and one group of data is formed in every transmission 3 times (that is: system time, temperature, shelf lifes).In addition, the data storage subroutine of this indicator, the real time data when being mainly used in the storage indicator operation is stored with the communication mode of I2C; When treating that the user requires indicator to communicate by letter with host computer, then call the real time data of storage, through serial ports with data transmission to computer, and store with the .txt text mode.

3. based on the indicator for forecasting shelf life of cold fresh pork of super low-power consumption embedded microprocessor MSP430F1XX, its shelf life computational algorithm is based on the shelf life of TTT (Time-Temperature-Tolerance) theoretical prediction cold fresh pork.Cold fresh pork has 5 indexs such as total volatile basic nitrogen (TVBN), index of fish freshness (K value), micro organism quantity (total plate count), subjective appreciation, pH value and can be used as its shelf life parameters calculated, this indicator is selected TVBN, K value, the total plate count parameter as one-level chemical dynamic model and Arrhenius equation, the shelf life of different rule calculating cold fresh porks in the alternation rule storehouse under different temperature conditions.

4. indicator for forecasting shelf life of cold fresh pork is selected the 5V lithium battery power supply for use, so the microprocessor of selecting for use is super low-power consumption chip MSP430F1XX, and during the operation of its each module fully independently, that is: timer, input/output end port, house dog, LCDs etc. can be under the state of host CPU dormancy independent operating.Chip MSP430F1XX operates in low-power consumption mode LMP0 (5V when the indicator operate as normal, 55uA), in the set time, wake up once enter activity pattern (5V, 300uA), in update system time, real time temperature, enter low-power consumption mode LMP0 behind the shelf life in real time.More do not use the indicator serviceable life of low-power consumption mode, this indicator is 4.75 times of the former serviceable life in life-span.

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