摘要： 现代社会的发展，对称重技术提出了更高的要求。目前，台式电子秤在商业贸易中的使用已相当普遍，但存在较大的局限性：体积大、成本高、需要工频交流电源供应、携带不便、应用场所受到制约。以单片机为控制核心的电子秤，具有功能强、体积小、功耗低、价格便宜、工作可靠等特点，广泛用于人们的日常生产生活之中，给人们的生活带来了极大的便利 。依此本课题设计一数字电子秤。该智能电子秤主要由电源、称重传感器、A/D转换器、单片机、键盘/开关、LCD显示器等部分组成。仪器主要功能有去皮、计价、单价设定、过载报警等。仪器若不进行称量操作，一段时间后自动进入休眠模式，降低电源消耗。95092

毕业论文关键词：数字电子秤， 称重传感器， A/D转换器， 显示器

Abstract：The development of the modern society has put forward higher request on weighing technology。 Currently, the desk-top electronic scales have been great application in commercial trade, but they have many shortcomings such as large volume, high cost, not inconvenience to carry and AC supply power, so they are restricted to use。 The usual portable scales are lever scales which are mostly used by residents and spring balance which measure through compression or drawing of spring。 They are being rejected for their big measuring errors。 People have been expecting cheap Intelligence electronic scales which can measure accurately and be carried conveniently for many years。This text designs a kind of intelligence electronic scales。Intelligence electronic scales consist of power, and weighs to spread the machine, A/D conversion, keyboard/switch, list slice, LCD etc。 Its technical indictors include : Measuring range from 0 to15 kg; Cent degree is 0。005 kg; Ⅲprecision。 The instrument possesses many intelligence functions, such as shelling, overload alarm, unit price enactment, accumulation computation, self-calibrating and so on。 For lowering power supply to consume, it can get into “sleep” automatically if the instrument is not measuring for 5 minutes。

Keyword: Intelligence electronic scales，Weigh to spread a feeling machine，A/D conversion， list slice

目   录

1 绪论 4

1。1称重技术和衡器的发展 4

1。2电子秤现在的发展现状以及未来的发展趋势 4

2 系统的总体设计 6

2。1电子秤系统的总体设计方案 6

3 系统硬件设计 6

3。1单片机最小系统设计 6

3。2 称重传感器的确定 9

3。3 24位的HX711型号的AD转换芯片 10

3。4 显示电路设计 13

3。5矩阵键盘电路 14

3。6声光报警子程序 15

3。7电源电路设计 15

4系统软件设计 16

4。1 主程序设计过程的软件流程图 16

4。2 A/D转换子程序设计 16

4。3时钟中断程序 17

4。4键盘扫描程序 17

4。5显示子程序 18

5 下载与调试 19

5。1 USB转串口驱动安装