查看“控制led亮度”的源代码

{{Language | Control Led Brightness}}   
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==目的==

本教程将教大家如何用Processing来控制LED灯的亮度。

==设备==
*'''[[Microduino-Core/zh]]'''
*'''[[Microduino-USBTTL/zh]]'''

*其他硬件设备
**USB数据连接线   一根 
**LED灯           一个
**330欧电阻        一个
**面包板           一个
**跳线             一盒

==原理图==


[[File:processingControlLEDBrightness原理图.jpg|600px|center|thumb]]


==程序==

[https://github.com/Microduino/Microduino_Tutorials/tree/master/Microduino_Processing/LEDBrightness LEDBrightness]

注意：代码里包含图片请不要丢掉

==调试==

步骤一：按着原理图搭建硬件环境，像这样：
[[File:processingControlLEDBrightness连接图.jpg|600px|center|thumb]]


步骤二：解释一下代码：

此代码可以随着鼠标的x轴的大小改变图片的亮度和控制小灯的亮度。

  void draw() {
    loadPixels();
  
    // We must also call loadPixels() on the PImage since we are going to read its pixels.  img.loadPixels(); 
    for (int x = 0; x < img.width; x++ ) {
      for (int y = 0; y < img.height; y++ ) {
  
        // Calculate the 1D pixel location
        int loc = x + y*img.width;
  
        // Get the R,G,B values from image
        float r = red (img.pixels[loc]);
        float g = green (img.pixels[loc]);
        float b = blue (img.pixels[loc]);
  
        // We calculate a multiplier ranging from 0.0 to 8.0 based on mouseX position. 
        // That multiplier changes the RGB value of each pixel.      
        float adjustBrightness = ((float) mouseX / width) * 8.0; 
        r *= adjustBrightness;
        g *= adjustBrightness;
        b *= adjustBrightness;
  
        // The RGB values are constrained between 0 and 255 before being set as a new color.      
        r = constrain(r,0,255); 
        g = constrain(g,0,255);
        b = constrain(b,0,255);
  
        // Make a new color and set pixel in the window
        color c = color(r,g,b);
        pixels[loc] = c;
      }
    }
    
    updatePixels();  
    
    //output r value to ledpin
    arduino.analogwrite(ledPin, int(r));
  }



步骤三：下载代码并编译通过。


步骤四：运行后鼠标在灯泡上横向移动，看看有什么反应。

==结果==

鼠标在左边灯泡最暗，在右边最亮，随着从左到右逐渐变化，processing的效果是这样的。

鼠标在左边：
[[File:processingOverLEDBrightness1.jpg|600px|center|thumb]]
鼠标在中间：
[[File:processingOverLEDBrightness2.jpg|600px|center|thumb]]
鼠标在右边：
[[File:processingOverLEDBrightness3.jpg|600px|center|thumb]]


实际中的LED灯也会做相应的明暗变化。

==视频==



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