 150-300    = GOOD
 75-150     = VERY GOOD
 0-75       = EXCELLENT
+
+The red, green, and blue pins are for an RGB LED.
  */
 
 int redpin = 9; // select the pin for the red LED

    lowpulseoccupancy = 0;
    starttime = millis();

    if (smallConcentration > 3000.0) { // air quality is VERY POOR
      analogWrite(redpin, 255);
      analogWrite(greenpin, 0);

/* Grove - Dust Sensor Demo v1.0
 Interface to Shinyei Model PPD42NS Particle Sensor
 Original Program by Christopher Nafis 
 Written April 2012
 Updated by Nate G, 2014
 
 http://www.seeedstudio.com/depot/grove-dust-sensor-p-1050.html
 http://www.sca-shinyei.com/pdf/PPD42NS.pdf
