基于單片機控制的霓虹燈控制器設(shè)計-資料下載頁
2024-11-17 21:33本頁面
【導(dǎo)讀】摘要：本設(shè)計采用AT89S51單片機實現(xiàn)對霓虹燈的控制。系統(tǒng)由單片機控制部分和顯示部分組成。顯示部分的128個發(fā)光二極管成8行16列矩陣式分布。單片機I/O口輸出的信號經(jīng)三極管放大驅(qū)動二極管發(fā)光。不同的控制信號使發(fā)光二極管以不同的方式和花樣顯示。方案一、采用移位寄存器擴展I/O口。綜上所述，考慮到要求控制的LBD不是太多，又矩陣式能形成較豐富的圖案，PCB板的布局和布線也較美觀，選擇方案二。綜上所述，三極管驅(qū)動電路簡單，性價比高，又能很好完成驅(qū)動作用，選擇方案一。 顯示部分主要由128個貼片發(fā)光二極管分成8圈，每圈16個組成，相當(dāng)于8行16列的矩陣。采用了1個AT89S51單片機，2個74HC373鎖存器，12M晶陣和一些相應(yīng)的電阻，插座。采用了矩陣式布局，可以較好的解決這一難題，但是受單片機I/O口的限制，能控制每一個LBD的數(shù)量有限。
【正文】 to machine intricate shapes that would be impossible to produce with conventional cutting tools. This machining process is continually finding further applications in the metalcutting industry. It is being used extensively in the plastic industry to produce cavities of almost any shape in the steel molds. Electrical discharge machining is a controlled metal removal technique whereby an electric spark is used to cut (erode) the workpiece, which takes a shape opposite to that of the cutting tool or electrode. The cutting tool (electrode) is made from electrically conductive material, usually carbon. The electrode, made to the shape of the cavity required, and the workpiece are both submerged in a dielectric fluid, which is generally a light lubricating oil. This dielectric fluid should be a nonconductor (or poor conductor) of electricity. A servo mechanism maintains a gap of about to in. ( to mm) between the electrode and the work, preventing them from ing into contact with each other. A direct current of low voltage and high amperage is delivered to the electrode at the rate of approximately 20 000 hertz (Hz). These electrical energy impulses bee sparks which jump the dielectric fluid. Intense heat is created in the localized area of the park impact, the metal melts and a small particle of molten metal is expelled from the surface of the workpiece . The dielectric fluid, which is constantly being circulated, carries away the eroded particles of metal and also assists in dissipating the heat caused by the spark.In the last few years, major advances have been made with regard to the surface finishes that can be produced. With the low metal removal rates, surface finishes of 2 to 4 um. ( to ) are possible. With high metal removal rates finishes of 1 000uin. (25um) are produced.The type of finish required determines the number of amperes which can be used, the capacitance, frequency, and the voltage setting. For fast metal removal (roughing cuts), high amperage, low frequency, high capacitance, and minimum gap voltage are required. For slow metal removal (finish cut) and good surface finish, low amperage, high frequency, low capacitance, and the highest gap voltage are required.Electrical discharge machining has many advantages over conventional machining processes.1. Any material that is electrically conductive can be cut, regardless of its hardness. It is especially valuable for cemented carbides and the new supertough spaceage alloys that are extremely difficult to cut by conventional means.2. Work can be machined in a hardened state, thereby overing the deformation caused by the hardening process.3. Broken taps or drills can readily be removed from workpieces. 4. It does not create stresses in the work material since the tool (electrode) never es in contact with the work.5. The process is burrfree.6. Thin, fragile sections can be easily machined without deforming.7. Secondary finishing operations are generally eliminated for many types of work.8. The process is automatic in that the servomechanism advances the electrode into the work as the metal is removed.9. One person can operate several EDM machines at one time.10. Intricate shapes, impossible to produce by conventional means, are cut out of a solid with relative ease.11. Better dies and molds can be produced at lower costs.12. A die punch can be used as the electrode to reproduce its shape in the matching die plate, plete with the necessary clearance.
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