devseed_dustduino.ino

// DUSTDUINO v1.0
// Released 18 October 2013
//
// This software is released as-is, without warranty,
// under a Creative Commons Attribution-ShareAlike
// 3.0 Unported license. For more information about
// this license, visit:
// http://creativecommons.org/licenses/by-sa/3.0/
//
// Written by Matthew Schroyer, except where specified.
// For more information on building a DustDuino, visit:
// http://www.mentalmunition.com/2013/10/measure-air-pollution-with-dustduino-of.html

/*888888888888888888888888888888888888888888888888888888888888888888888888888888888888*/

// WiFlyHQ Library written by Harlequin-Tech.
// Available at: https://github.com/harlequin-tech/WiFlyHQ
#include <WiFlyHQ.h>
#include <avr/wdt.h>

unsigned long starttime;

unsigned long triggerOnP1;
unsigned long triggerOffP1;
unsigned long pulseLengthP1;
unsigned long durationP1;
boolean valP1 = HIGH;
boolean triggerP1 = false;

unsigned long triggerOnP2;
unsigned long triggerOffP2;
unsigned long pulseLengthP2;
unsigned long durationP2;
boolean valP2 = HIGH;
boolean triggerP2 = false;

float ratioP1 = 0;
float ratioP2 = 0;
unsigned long sampletime_ms = 30000;
float countP1;
float countP2;

WiFly wifly;
void terminal();

const char ARDUINO_KEY[] = "YOUR ARDUINO KEY";
const char server[] = "YOUR SERVER ADDRESS";

void setup(){
 Serial.begin(9600);
 wifly.begin(&Serial, NULL);
 pinMode(8, INPUT);
 wdt_enable(WDTO_8S);
 starttime = millis();
}

void loop(){
 
 valP1 = digitalRead(8);
 valP2 = digitalRead(9);
 
 if(valP1 == LOW && triggerP1 == false){
 triggerP1 = true;
 triggerOnP1 = micros();
 }
 
 if (valP1 == HIGH && triggerP1 == true){
 triggerOffP1 = micros();
 pulseLengthP1 = triggerOffP1 - triggerOnP1;
 durationP1 = durationP1 + pulseLengthP1;
 triggerP1 = false;
 }
 
 if(valP2 == LOW && triggerP2 == false){
 triggerP2 = true;
 triggerOnP2 = micros();
 }
 
 if (valP2 == HIGH && triggerP2 == true){
 triggerOffP2 = micros();
 pulseLengthP2 = triggerOffP2 - triggerOnP2;
 durationP2 = durationP2 + pulseLengthP2;
 triggerP2 = false;
 }
 
 wdt_reset();

 // Function creates particle count and mass concentration
 // from PPD-42 low pulse occupancy (LPO).
 if ((millis() - starttime) > sampletime_ms) {
 
 // Generates PM10 and PM2.5 count from LPO.
 // Derived from code created by Chris Nafis
 // http://www.howmuchsnow.com/arduino/airquality/grovedust/
 
 ratioP1 = durationP1/(sampletime_ms*10.0);
 ratioP2 = durationP2/(sampletime_ms*10.0);
 countP1 = 1.1*pow(ratioP1,3)-3.8*pow(ratioP1,2)+520*ratioP1+0.62;
 countP2 = 1.1*pow(ratioP2,3)-3.8*pow(ratioP2,2)+520*ratioP2+0.62;
 float PM10count = countP2;
 float PM25count = countP1 - countP2;
 
 // Assues density, shape, and size of dust
 // to estimate mass concentration from particle
 // count. This method was described in a 2009
 // paper by Uva, M., Falcone, R., McClellan, A.,
 // and Ostapowicz, E.
 // http://wireless.ece.drexel.edu/research/sd_air_quality.pdf
 
 // begins PM10 mass concentration algorithm
 double r10 = 2.6*pow(10,-6);
 double pi = 3.14159;
 double vol10 = (4/3)*pi*pow(r10,3);
 double density = 1.65*pow(10,12);
 double mass10 = density*vol10;
 double K = 3531.5;
 float concLarge = (PM10count)*K*mass10;
 
 // next, PM2.5 mass concentration algorithm
 double r25 = 0.44*pow(10,-6);
 double vol25 = (4/3)*pi*pow(r25,3);
 double mass25 = density*vol25;
 float concSmall = (PM25count)*K*mass25;
 
 sendData(concLarge, concSmall, PM10count, PM25count);
 
 durationP1 = 0;
 durationP2 = 0;
 starttime = millis();
 wdt_reset();
 }
 }
 
 // WiFly HTTP connection to the Xively server.
 // Patchube client originally written 15 March 2010 by Tom Igoe,
 // Usman Haque, and Joe Saavedra at http://arduino.cc/en/Tutorial/PachubeCient
 // Modified to work with WiFly RN-XV and Xively.
void sendData(int PM10Conc, int PM25Conc, int PM10count, int PM25count) {
 wifly.open(server, 80);
 wifly.println("POST /api/v1/readings/ HTTP/1.1");
 wifly.print("Host: "); wifly.println(server);
 wifly.print("Authorization: Token ");wifly.println(ARDUINO_KEY);
 wifly.println("User-Agent: Arduino/1.0");
 wifly.print("Accept: *");wifly.print("/");wifly.println("*");
 wifly.println("Referer:");
 wifly.print("Content-Length: ");

 // Calculates the length of the sensor reading in bytes:
 int thisLength = 33 + getLength(PM10Conc) + getLength(PM25Conc) + getLength(PM10count) + getLength(PM25count);
 wifly.println(thisLength);

 // last pieces of the HTTP POST request:
 wifly.println("Content-Type: application/x-www-form-urlencoded");
 wifly.println("Connection: close");
 wifly.println();

 // here's the actual content of the POST request:
 wifly.print("pm10=");
 wifly.print(PM10Conc);
 wifly.print("&pm25=");
 wifly.print(PM25Conc);
 wifly.print("&pm10count=");
 wifly.print(PM10count);
 wifly.print("&pm25count=");
 wifly.println(PM25count);
 wifly.close();
}
 
 // This function also is derived from
 // the Patchube client sketch. Returns
 // number of digits, which Xively needs
 // to post data correctly.
 int getLength(int someValue) {
 
 int digits = 1;
 if (someValue < 0) {
 someValue = someValue * -1;
 digits = 2;
 }
 int dividend = someValue /10;
 while (dividend > 0) {
 dividend = dividend /10;
 digits++;
 }
 return digits;
}

// This function connects the WiFly to serial.
// Developed by Harlequin-Tech for the WiFlyHQ library.
// https://github.com/harlequin-tech/WiFlyHQ

void terminal()
{
 while (1) {
	if (wifly.available() > 0) {
	 Serial.write(wifly.read());
	}


	if (Serial.available() > 0) {
	 wifly.write(Serial.read());
	}
 }
}