Mirror the onboard RGB LED on Particle devices to an external RGB LED

ledmirror.cpp

// Automatically mirror the onboard RGB LED (Photon, Electron) to an external RGB LED

// LEDMirror.cpp
// Class set-up 
class LEDMirror {
  public:
    LEDMirror(pin_t r, pin_t g, pin_t b) : pin_r(r), pin_g(g), pin_b(b) {
      pinMode(pin_r, OUTPUT);
      pinMode(pin_g, OUTPUT);
      pinMode(pin_b, OUTPUT);
      RGB.onChange(&LEDMirror::handler, this);
    }

    void handler(uint8_t r, uint8_t g, uint8_t b) {
      analogWrite(pin_r, 255 - r);
      analogWrite(pin_g, 255 - g);
      analogWrite(pin_b, 255 - b);
    }

    private:
      pin_t pin_r;
      pin_t pin_g;
      pin_t pin_b;
};

// myProject.ino
// Example Usage: Connect an external RGB LED to D0, D1 and D2 (R, G, and B) and place this in your user firmware
LEDMirror myLED(D0, D1, D2);