This graduation project is the design and production of electronic weighing system which is based on the STC single-chip microcomputer. Electronic scale is a commonly used measurement instruments. Compared with ordinary equipment, digital electronic scale has such characteristics as rapid weighing, intuitive readings, stable performance, accurate measuring.
In this paper, the electronic weighing system uses low power, low-cost controller chips STC 12 Series comes with A/D converter single-chip microcomputer to design a small size, low power, accurate weighing, easy to use, low-cost electronic scale with multi-function display and it has the ability of serial communication with PC.
The electronic weighing system designed in this graduation project uses resistance strain gauge load cell to convert the weight of detected objects to millivolt level analog voltage signal. The small voltage signal is amplified accurately and linearly through the instrumentation amplifier to to meet the A / D converter input signal level required. The amplified analog voltage signal through A / D conversion circuit convert to digital, the single-chip microcomputer control system then processed through the data conversion before The digital signal stored into the register. Through the keyboard function keys,it can transport digital signals into the display circuit and the measurement results can be displayed by the four seven-segment LED digital tube. It can also switch the function key to input the numbers keys as the unit price,or figure out the total prices and displayed . Moreover,it has the function of serial communication ,and the measurement results can be uploaded to PC.
