arduino - Arduino中的定时褪色

Question

我需要编写一个 Arduino 函数来交叉淡化两个可变频率的 LED。即 - 当第一个 LED 达到峰值时，第二个 LED 开始淡入。此外，最好它应该在没有 delay() 的情况下运行，因为存在并发代码。我想我会使用 SoftPWMLibrary，但我不知道如何确定淡入淡出的时间。

Answer 1

看看这个http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1231200459#2。我用过那个解决方案，效果很好！

Answer 2

也许你可以添加这个

class fade 
{
private:
  uint8_t _min;
  uint8_t _max;
  uint8_t _to;
  uint8_t _dutyCycle;
  uint32_t _time;
  uint32_t _last;
  int _pin;

public:
  fade ( int pin, uint32_t timeStep=10000, uint8_t min=0, uint8_t max=255)
  {
    _pin = pin;
    _time = timeStep;
    _min = min;
    _max = max;
    analogWrite(_pin,_min);
    _dutyCycle = _min;
  }
  void write(int to)
  {
    _to = (uint8_t) constrain(to,_min,_max);

    this->update();
  }

  void update()
  {
    this->update( micros() );
  }

  void update(uint32_t time)
  {
    if(time + _time > _last)
    {
      _last = time;
      if(_dutyCycle > _to) analogWrite(_pin,--_dutyCycle);
      if(_dutyCycle < _to) analogWrite(_pin,++_dutyCycle);
    }
  }

  uint8_t read()
  {
    return _dutyCycle;
  }

  uint32_t readSpeed()
  {
    return _time;
  }

  uint32_t writeSpeed(uint32_t time)
  {
    _time=time;
  }
};

/*now create a fade object
* fade foo(pin, timestep, min, max)
* timeStep is by default 10000 us (10 ms)
* min is by default 0
* max is by default 255
*
* example
* fade foo(13) is the same as fade foo(13, 10000, 0, 255)
*
* to change the speed once declared.
* foo.writeSpeed(new speed);
* to read the current speed
* foo.readSpeedspeed();
*
* foo.read() returs the current fade level ( pwm dutyCycle);
* foo.write( to ) defines the new endpoint of the fader;
* 
* foo.update(); needs to called in the loop
* foo.update( time); is for saving time if more time relating objects;
* unsigned long a = micros();
* foo.update(a);
* bar.update(a);
* foobar.update(a);
* is faster than redefine time every update
*/

fade led1(11);// fader pin 11 speed 10 ms/ step
fade led2(10,100000);// fader pin 10 speed 100 ms / step;

void setup()
{
  led2.write(128); //fade to half
  led1.write(255); //fade to max

  //setup
}

void loop()
{
  unsigned long time = micros();
  led1.update(time);
  led2.update(time);

  // loop
}

这未经测试，但应该可以工作