按照图片所示进行连接:
光敏电阻的电阻大小与光亮度成反比,通过测量电阻的电压可以知道光敏电阻的电阻大小,从而知道光亮度。
代码:
#define LED_GREEN 9//定义与绿灯连接的引脚
#define LED_RED 10//定义与红灯连接的引脚
int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by
void setup()
{
pinMode(LED_GREEN,OUTPUT);
pinMode(LED_RED,OUTPUT);
Serial.begin(9600); // 打开串口,设置波特率为9600 bps
}
void loop()
int i;
while(1)
{
i=analogRead(5);//读模拟口5
Serial.println(i,DEC);//从串口发送字符串并换行
if(i>400)//有光时,根据实际情况修改此数值
{
// set the brightness of pin 9:
analogWrite(LED_GREEN, brightness);
analogWrite(LED_RED, 0);
// change the brightness for next time through the loop:
brightness = brightness + fadeAmount;
// reverse the direction of the fading at the ends of the fade:
if (brightness == 0 || brightness == 255) {
fadeAmount = -fadeAmount ;
}
// digitalWrite(LED_GREEN,HIGH);//绿灯亮
// digitalWrite(LED_RED,LOW);//红灯灭
// delay(1000); //设定延时时间,1000 = 1秒
// digitalWrite(LED_GREEN,LOW);//绿灯亮
}else
analogWrite(LED_RED, brightness);
analogWrite(LED_GREEN, 0);
// digitalWrite(LED_RED,HIGH);//红灯亮
// digitalWrite(LED_GREEN,HIGH);//绿灯灭
// digitalWrite(LED_RED,LOW);//红灯亮
}
delay(30);
}
编译并上传以后,当光敏电阻无遮挡时,绿色LED从暗到亮,再从亮到暗交替进行。当遮挡住光敏电阻时,红色LED开始同样的动作。查看串口数据可以看到电阻电压的模拟值(0-1024区间,最大值1024)
这儿的代码中还有一点需要修改的地方,例如遮挡住光敏电阻,红色LED的亮度是绿色LED熄灭前最后一刻的亮度。