arduino-coffeescript-playground/dust_sensor/dust-sensor.coffee

#  JST Pin 1 (Black Wire)  => Arduino GND
#  JST Pin 3 (Red wire)    => Arduino 5VDC
#JST Pin 4 (Yellow wire) => Arduino Digital Pin 8
#*/
#
#int pin = 8;
#unsigned long duration;
#unsigned long starttime;
#unsigned long sampletime_ms = 30000;//sampe 30s ;
#unsigned long lowpulseoccupancy = 0;
#float ratio = 0;
#float concentration = 0;
#void setup() {
#  Serial.begin(9600);
#  pinMode(8,INPUT);
#  starttime = millis();//get the current time;
#}
#
#void loop() {
#  duration = pulseIn(pin, LOW);
#  lowpulseoccupancy = lowpulseoccupancy+duration;
#
#  if ((millis()-starttime) > sampletime_ms)//if the sampel time == 30s
#  {
#    ratio = lowpulseoccupancy/(sampletime_ms*10.0);  // Integer percentage 0=>100
#concentration = 1.1*pow(ratio,3)-3.8*pow(ratio,2)+520*ratio+0.62; // using spec sheet curve
#Serial.print(lowpulseoccupancy);
#Serial.print(",");
#Serial.print(ratio);
#Serial.print(",");
#Serial.println(concentration);
#lowpulseoccupancy = 0;
#starttime = millis();
#}
#}