爱站程序员基地Arduino初学IO控制，流水灯实验是很好的学习对象。分两个进程学习。一、假流水灯，即基础效果实现二、真流水灯，即采用PWM模拟真实流水渐变效果
我们设立5盏灯，正极分别连接数字口（Digital Pin）3 5 9 10 11口 ，负极共地（GND）
假流水灯
int LED1 = 3;int LED2 = 5;int LED3 = 9;int LED4 = 10;int LED5 = 11;void setup() {pinMode(LED1, OUTPUT);pinMode(LED2, OUTPUT);pinMode(LED3, OUTPUT);pinMode(LED4, OUTPUT);pinMode(LED5, OUTPUT);}void loop() {//状态1digitalWrite(LED1, 1); //1 代表 HIGH 0 代表 LOWdigitalWrite(LED2, 0);digitalWrite(LED3, 0);digitalWrite(LED4, 0);digitalWrite(LED5, 0);delay(1000);//状态2digitalWrite(LED1, 0);digitalWrite(LED2, 1);digitalWrite(LED3, 0);digitalWrite(LED4, 0);digitalWrite(LED5, 0);delay(1000);//状态3digitalWrite(LED1, 0);digitalWrite(LED2, 0);digitalWrite(LED3, 1);digitalWrite(LED4, 0);digitalWrite(LED5, 0);delay(1000);//状态4digitalWrite(LED1, 0);digitalWrite(LED2, 0);digitalWrite(LED3, 0);digitalWrite(LED4, 1);digitalWrite(LED5, 0);delay(1000);//状态5digitalWrite(LED1, 0);digitalWrite(LED2, 0);digitalWrite(LED3, 0);digitalWrite(LED4, 0);digitalWrite(LED5, 1);delay(1000);}
使用状态控制法去实现，方便理解和修改，每个状态持续一段时间，即使用
delay()
。【Arduino程序的运行机制和Processing不太一样，P5是等待一次draw函数执行完才刷新画布，得到结果，而Arduino是即时，也就是执行一条语句后立马能反馈到结果！！】当然有人用循环语句来搭建，可以，但是对初学者真是不友好。首先循环语句本来就不熟悉，而且还有
delay延迟函数
参与，不好理解其运行逻辑的，所以不推荐。
真流水灯
因为要模拟过渡效果，因此简单的数字式读写没法满足要求，使用PWM调节机制能模拟出来。
int LED1 = 3;int LED2 = 5;int LED3 = 9;int LED4 = 10;int LED5 = 11;int fadeValue1 = 0; //定义亮度int fadeValue2 = 60;int fadeValue3 = 120;int fadeValue4 = 180;int fadeValue5 = 240;int state1 = 0;int state2 = 0;int state3 = 0;int state4 = 0;int state5 = 0;void setup() {}void loop() {//更新//1if (state1 == 0){fadeValue1 += 1;}else if(state1 == 1){fadeValue1 -= 1;}if (fadeValue1 > 254){state1 = 1;}else if (fadeValue1 < 1){state1 = 0;}////////////////2/////////////////////////if (state2 == 0){fadeValue2 += 1;}else if(state2 == 1){fadeValue2 -= 1;}if (fadeValue2 > 254){state2 = 1;}else if (fadeValue2 < 1){state2 = 0;}////////////////3/////////////////////////if (state3 == 0){fadeValue3 += 1;}else if(state3 == 1){fadeValue3 -= 1;}if (fadeValue3 > 254){state3 = 1;}else if (fadeValue3 < 1){state3 = 0;}////////////////4/////////////////////////if (state4 == 0){fadeValue4 += 1;}else if(state4 == 1){fadeValue4 -= 1;}if (fadeValue4 > 254){state4 = 1;}else if (fadeValue4 < 1){state4 = 0;}////////////////5/////////////////////////if (state5 == 0){fadeValue5 += 1;}else if(state5 == 1){fadeValue5 -= 1;}if (fadeValue5 > 254){state5 = 1;}else if (fadeValue5 < 1){state5 = 0;}//执行 相当于 P5绘画analogWrite(LED1, fadeValue1);analogWrite(LED2, fadeValue2);analogWrite(LED3, fadeValue3);analogWrite(LED4, fadeValue4);analogWrite(LED5, fadeValue5);delay(4);}
沿用P5的
更新-绘画
原理,慢慢地刷新亮度值，最后统一执行
analogWrite()
。不过还能简化一些操作，使用
sin函数
来更新数值，如：
int LED1 = 3;int LED2 = 5;int LED3 = 9;int LED4 = 10;int LED5 = 11;int fadeValue1 = 0;int fadeValue2 = 60;int fadeValue3 = 120;int fadeValue4 = 180;int fadeValue5 = 240;//为了方便 偏移 sin函数的相位，设置一个不同的初相int state1 = 0;int state2 = 10;int state3 = 20;int state4 = 30;int state5 = 40;void setup() {// put your setup code here, to run once:// analogWrite 函数不用pinMode定义}void loop() {fadeValue1 = abs(cos(millis()/200.0 + state1)) * 250 + 1;fadeValue2 = abs(cos(millis()/200.0 + state2)) * 250 + 1;fadeValue3 = abs(cos(millis()/200.0 + state3)) * 250 + 1;fadeValue4 = abs(cos(millis()/200.0 + state4)) * 250 + 1;fadeValue5 = abs(cos(millis()/200.0 + state5)) * 250 + 1;// analogWrite(LED1, fadeValue1);// analogWrite(LED2, fadeValue2);// analogWrite(LED3, fadeValue3);// analogWrite(LED4, fadeValue4);// analogWrite(LED5, fadeValue5);analogWrite(LED1, 255-fadeValue1);analogWrite(LED2, 255-fadeValue2);analogWrite(LED3, 255-fadeValue3);analogWrite(LED4, 255-fadeValue4);analogWrite(LED5, 255-fadeValue5);delay(4);}
因为sin函数的数值变化本就带缓动，因此效果很理想。
上述代码只是模型参考，任意数值都能自行修改。其实这里应该贴上实验结果来完善这篇博文，但是么。。。为了保有读者的好奇心，鼓励读者自行实操看效果，这也是学习硬件，学习Arduino另外的乐趣和意义，祝好运 ！ @~
