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Scale solution
The types of scales can be divided into: electronic scales, mechanical scales (pointer scales). Scales can also be divided into scales with a height scale and scales without a height scale. There is also a body fat scale, which is a kind of electronic scale. In addition to measuring body weight, it can also measure fat, calories, bones, water and other contents.
The scale can accurately measure a person's weight, and through the daily weight change, it can reflect the weight control situation of a certain period of time. The height and weight scale uses ultrasonic technology to measure height (no touch); the precision sensor measures weight, which can simultaneously display the results of height and weight. Traditional height and weight scales can only measure weight or height, and have a single function. Based on this consideration, we have designed a human body interesting height and weight scale, which can use 5 LED lights to indicate the fat and thin of the human body, which increases the interest of the height and weight scale. and practicality.
1. Interesting height and weight scale structure
A fun height and weight scale for the human body is designed using pressure sensors and ultrasonic sensors, and its structure diagram is shown in Figure 1.
The human body interesting height and weight scale includes: scale base, pressure sensor module, scale pole, ultrasonic sensor module, single chip microcomputer minimum system, five indicator lights, power supply, gender selection button, etc. The vertical pole of the scale is fixed vertically on the base of the scale, the pressure sensor module and power supply are installed inside the base of the scale, the gender selection button is installed on the side of the pole of the scale, the ultrasonic sensor module is fixed on the top of the pole of the scale, the pressure sensor module and The voltage signals output by the ultrasonic sensor module are all sent to the minimum system of the single-chip microcomputer, and the minimum system of the single-chip microcomputer sends the processing results to five indicator lights for display.
2. Circuit Design of Height and Weight Scale
The single-chip microcomputer is easy to program and low in cost, and it is widely used in many control fields. The minimum system circuit of a single-chip microcomputer, including a single-chip microcomputer, a crystal oscillator circuit that provides a clock, a reset circuit for initialization, and a power supply circuit. The AT89S5X MCU has 40 ports, and when the P0 port is used, the level is generally pulled high by connecting the row resistance. The single-chip microcomputer in the single-chip minimum system internally stores the relational expression of the height and weight of men and women, and the output signal of the single-chip minimum system controls one of the five indicator lights to light up.
The power supply is a 5 volt DC power supply, its positive pole is connected to the 40 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer, and the negative pole is connected to the 20 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer. One end of the gender selection button is connected to the negative pole of the power supply (11), and the other end is connected to the 25 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer.
The circuit unit of the human body height and weight scale is shown in Figure 3. The pressure sensor module includes a pressure sensor [4-6], an amplifier and an A/D converter. The pressure sensor module is externally connected to 4 pins, which are the power supply Vcc, the clock SCK, Data output DT, ground GND, these 4 pins are inserted into the needle header and lead out with leads, in which the power supply Vcc is connected to 40 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer, the clock SCK is connected to the 26 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer, and the data The output DT is connected to the 27 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer, and the ground GND is connected to the 20 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer.
The ultrasonic sensor module is externally connected to 4 pins, which are power supply VCC, ground GND, digital signal DO, and analog signal AO. Its power supply VCC and ground GND are respectively connected to the positive and negative poles of the power supply, and the output analog signal AO is sent to the 28 pins of the single-chip microcomputer in the minimum system board of the single-chip microcomputer, and its digital signal DO pin is not connected.
The negative poles of the five LED indicator lights [7-8] are connected in series with a 470 ohm resistor and then connected to pin 20 of the single-chip microcomputer in the minimum system of the single-chip microcomputer. Red light is sent out when indicator light (6) is lighted, and expression is obese. The positive pole of the second indicator light is connected to the 38 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer, and when the second indicator light is lit, it emits a yellow light, indicating that the weight is heavy. The positive pole of the third indicator light is connected to the 37 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer. When the third indicator light is lit, it emits green light, indicating that the weight is normal. The positive pole of the fourth indicator light is connected to the 36 pins of the single-chip microcomputer in the minimum system of the single-chip microcomputer. When the fourth indicator light is lit, blue light is emitted, indicating that the weight is light. The positive pole of the 5th indicator light connects the 35 pins of the single-chip microcomputer in the minimum system (5) of the single-chip microcomputer, and when the 5th indicator light is lighted, white light is sent out, and expression is underweight.
3. Software design of height and weight scale
When the MCU program is running, first read the values of the pressure sensor module and the ultrasonic sensor module, and judge whether someone has stepped on the fun height and weight scale according to the sensor values. When someone stands on the fun height and weight scale, choose whether to press the Gender selection button, according to the body fat and thin standard of the World Health Organization, male: (height-80)×70%=standard weight, female: (height-70)×60%=standard weight, wherein the unit of height is centimeters. Standard weight plus or minus 10% is normal weight, standard weight plus or minus 10% to 20% is overweight or underweight, standard weight plus or minus 20% is obesity or underweight, and the minimum system of single-chip microcomputer is judged according to the standards of the World Health Organization The human body is fat or thin, and the output result is controlled by the indicator light to give instructions. When the minimum system of the single-chip microcomputer judges that the person has stepped off the interesting height and weight scale, all the indicator lights are turned off and the values of the pressure sensor module and the ultrasonic sensor module are read again.
Using the minimum system of single chip microcomputer, pressure sensor module, ultrasonic sensor module, LED lights and other components, an interesting height and weight scale for human body is designed. The signals output by the pressure sensor module and the ultrasonic sensor module are sent to the minimum system of the single-chip microcomputer for processing, and the body weight and height data are obtained. The gender selection button is innovatively designed, and whether to press the gender selection button is selected according to the gender of the tester. The body fat and thin standards stipulated by the World Health Organization are stored to judge the fat and thin degree of the human body, and the minimum system of the single-chip microcomputer uses the processing results to control five indicator lights to display the fat and thin.
4. Smart weighing scale design
1. Brief Introduction of Smart Scale Based on Internet of Things Technology
Current weighing scales only have the function of weighing body weight, and cannot store these data, nor can they give weight change trends, nor can they give reminders when the user's weight exceeds the standard.
Record the trend of weight change, and remind the user by sending text messages when the weight exceeds a certain threshold value, which is an effective auxiliary means for people who control their weight. Especially for developing babies, people with high blood pressure, high blood sugar and other physical conditions that are closely related to their weight, this function can not only help doctors understand the patient's weight change trend, but also help users understand their own physical illness changes and records, so as to provide a basis for future nutrition plans and improve the rationality, pertinence and scientific nature of fitness activities. In addition, by recording the weight change data of the majority of users and conducting big data analysis, we can understand various indicators such as the nutritional status of the population in our country, the level of living development, and the relationship between weight and disease.
With the improvement of people's living standards, people's pursuit of health is getting higher and higher; with the development of Internet of Things big data mobile Internet technology and its application in various industries, the application of collecting data through the Internet of Things and transmitting it to the big data platform for analysis There are more and more patterns.
New functions are added on the basis of the existing weight scale, and the traditional weight scale is transformed to have the function of wireless transmission. That is, after the user has weighed himself, he presses the button, and the weight value will be transmitted to the receiving platform through the wireless transmission device. The receiving platform will store the received data and analyze the data. If the data exceeds the preset threshold, it will send a text message to the user through the SMS gateway during the meal time to remind the user to pay attention to diet, so as to help the user monitor their own weight. purpose of control. In addition, the weight value can also be recorded and a weight change curve can be generated.
2. Smart weighing scale solution architecture
The design of the intelligent weighing scale based on the Internet of Things technology includes: the main body of the weighing scale, a communication server, a database server, a web server, and a mobile terminal application. The communication server, the database server and the web server together constitute the background server of the weight management system. The mobile terminal application is installed on the smart phone and is connected with the weight management system through the mobile network. The block diagram of the system is shown in Figure 1.
(1) Main body of the scale: In addition to the weighing function of ordinary scales, the scale also has a wireless communication module, which has the function of sending data to the external network through wireless communication technology. Considering that each scale in a family may be used by multiple people, design a number of buttons when designing the scale, and each button corresponds to a person. Each scale has a globally unique SN, which is used to distinguish different scales. SN plus button number is used to uniquely determine a user. In the data transmission protocol, it is necessary to specify that the SN and button number data are sent to the communication server through the TCP protocol. Each scale is a TCP client. Through a wireless network connection, access to a communication server with a fixed IP address. SN, button number and weight data constitute a data packet and send it at a time. Every time you weigh an overweight weight, the scale has a process of establishing a connection, sending data, and disconnecting.
(2) Communication server: The main function of the communication server is to act as the server side of the TCP connection. The communication server program accepts the connection from the weighing scale, analyzes the data, obtains the SN of the weighing scale, the button number, and the weight value, and writes the information into the database. When there are a large number of devices, the pressure on the communication server is relatively high. For this reason, the communication server adopts an asynchronous connection to receive data from the weighing scale. In the actual development, it is found that due to the wireless connection sometimes there will be a false connection phenomenon, that is, the device has actually been disconnected, but the instability of the wireless connection will create a false impression that the connection on the server side is still maintained, and it will not be disconnected by itself. Lose. The disadvantage of this false connection phenomenon is that when the communication program runs for too long, the total number of connections will exceed the maximum number of connections that the server can receive, so new devices cannot be connected. In order to avoid this phenomenon, the data sending time of each connection can be monitored. If it is found that there is no data to send and receive within 10 minutes, the server-side program will actively disconnect. Another function of the communication server is to write data into the database. When there are a large number of devices, the pressure of concurrent access is high. In order to reduce the pressure on the database, two measures are taken: one is to use the database connection pool mechanism; the other is to store the data within 1 minute in the memory. After 1 min, it will be uniformly written into the database. This greatly reduces the pressure on database access.
(3) Database server: The database server adopts MongoDB database. MongoDB is a high-performance, open-source, schema-less document-type distributed document storage database written in C++ language. It aims to provide scalable high-performance data storage solutions for web applications. It is currently one of the more popular Nosql databases. It can be used as an alternative to traditional relational databases or key/value stores in many scenarios. MongoDB is a product between a relational database and a non-relational database. It is the most functional and most like a relational database among non-relational databases. The data structure it supports is very loose, which is a bjson format similar to json, so it can store more complex data types. Its biggest feature is that the supported query language is very powerful, and its syntax is somewhat similar to object-oriented query language, which can almost realize most of the functions similar to single-table query of relational database, and also supports indexing of data. It has the characteristics of high performance, easy deployment, easy use, and convenient data storage. And MongoDB can be used as the data source and data storage destination library of Hadoop MapReduce through the connector, which lays the foundation for future big data analysis.
(4) Web server: The web server provides a program of B/S architecture, which is used to support users to access their own weight data from the PC or mobile phone, view the weight change curve and the weight threshold filled in by the user in advance, when the weight exceeds the threshold , a text message will be sent through the SMS gateway to remind the user to pay attention to diet.
3. Smart scale hardware design
Improving the traditional weighing scale and designing a low-cost, low-power weighing scale with wireless transmission function is another focus.
(1) Weight scale hardware module: The device is powered by batteries, and can collect data from the gravity sensor through A/D, process the obtained original information according to a certain algorithm, and display the currently collected sample value through LCD. Users can interact with nodes through key operations and upload data to the platform. Connect the GPRS wireless communication module through the serial port. This module can transmit the collected data to the remote platform. The low-power MSP430 processor is used, and the battery is divided into 3 circuits to supply power to the gravity sensor, processor, display and wireless module. This can achieve the purpose of saving energy consumption.
(2) Hardware low-power design: The hardware design is divided into three parts according to the function and the needs of low-power design. The center of its design is low power consumption design. The first part is the design of the sensor circuit. The sensor circuit amplifies and shapes the original analog signal so that the MCU can perform A/D acquisition; the second part is the design of the digital circuit and man-machine interface, including A/D acquisition, LCD real-time data and Status display and sending data and status to the wireless module in real time; the third part is the application design of the wireless module, mainly the power supply and data interface design of the wireless module. The key technologies of low-power hardware design are technologies such as power division, isolation, and low power consumption.
The above are the details of the weighing scale solution introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have electronic function development needs for human health scales and body fat scales, you can rest assured to entrust them to us. We have rich experience in customized development of electronic products, and can evaluate the development cycle and IC price as soon as possible, and can also calculate PCBA quotations. We are a number of chip agents at home and abroad, including MCU, voice IC, Bluetooth IC and modules, wifi modules. Our development capabilities cover PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development and other hardware and software design. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS solutions, the development of Bluetooth audio, the development of children's toys, and the development of electronic education products.
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