Electronic scales are a very common and indispensable tool in people's daily life. They are mainly used to measure quality in commodity trade. They are used in a wide range of fields, from commodity grocery stores to industrial and agricultural, medical and other fields. . Infiltrating into all aspects of people's lives, compared with traditional mechanical scales, the development of modern electronic scales tends to be miniaturized and intelligent, and has the advantages of light weight, low cost, and high speed, but still has certain limitations, such as It is required to have higher anti-interference ability and higher precision. Considering the cost performance, stability and accuracy of the electronic weighing instrument, a high-precision digital electronic scale with multi-function, small power consumption, easy to use and fast speed is designed. The high-precision electronic scale adopts STC15W408S single-chip microcomputer as the main control component, and connects each sub-module. The sub-module mainly includes power supply module, signal acquisition and conversion module, LCD display module, keyboard module and alarm module. The system schematic diagram is shown in Figure 1. Figure 1 Block diagram of the electronic scale system The power module is used to provide a +5V DC stabilized voltage to the system. When the measured object is placed on the weighing pan, the pressure of the object is transmitted to the bridge varistor sensor. At this time, the sensor is deformed due to uneven force, the resistance value changes, and the bridge imbalance output and the The analog voltage signal is proportional to the weight of the object, and the analog voltage signal is amplified and converted into a high-precision digital signal by the A/D conversion chip HX711, and sent to the single-chip microcomputer for storage and processing. When the keyboard module has a button press, the MCU will perform necessary judgment and analysis, and according to the function of the button, perform corresponding functions such as peeling, weighing, calculation, display, query, alarm, and the like. The hardware circuit of the electronic scale consists of various modules with different functions. Each module is independently designed and tested, and finally combined into a whole and tested for performance. Considering the price and performance requirements, the STC15W408S MCU is used in the information control and processing module. Not only can the STC15W408S achieve measurement and control requirements, but its performance is lighter, smaller, and lower in power consumption. The portability of the electronic scale. Its pin circuit is shown in Figure 2. Figure 2 STC15W408S pin circuit diagram STC15W408S is a low-power, high-performance 8-bit microcontroller manufactured by STC. It has 8K bytes of system programmable flash memory, 512 bytes of RAM, 42 I/O lines, 5KB of internal EEPROM, and 3 16 bits. Timer/counter and supports full-duplex serial communication, power-down wake-up, external interrupt, etc. SC/APC Fiber Optic Fast Connector Sc/Apc Fiber Optic Fast Connector,Fiber Optic Adaptor Fast Connector,Fiber Quick Connect Kit,Sc Fiber Optic Fast Connector Ningbo Fengwei Communication Technology Co., Ltd , https://www.fengweicommunication.com
Design of high precision electronic scale based on HX711
introduction