Breath-over-IP for Arduino

This is the code for breath-over-IP for an Arduino. This code uses the NewSoftSerial library, and assumes the use of a Lantronix Xport / Xport Direct (perhaps with a LadyAda Ethernet Shield).

#include <NewSoftSerial.h>

// breath-over-IP for Arduino

unsigned long time = 0;   // time of last edge
int minTime = 25;         // minimum time for edge
int good = 0;             // number of consecutive good (fast) edges
int minGoods = 20;        // minimum number of consecutive good (fast) edges to indicate breath

int ledPin = 13;          // on-board LED pin        
int irLedPin = 10;        // IR LED attached to pin 12 with 220 ohm resistor
int irDetPin = 0;         // IR phototransistor attached to analog 0 with 5V and 10K
int relayPin = 11;        // solid-state relay pin

unsigned long onTime = 0; // relay on time'

int i=0;                  // counts up received breath packets for diagnostics
int light=0;              // whether IR detector sees light or dark
int lastLight=0;          // what IR detector saw last time
int state=0;              // current state of state machine for reading HTTP

char c=0;

unsigned long sendTime=0; // last time breath packet was sent out

NewSoftSerial xport(3,2);

void setup()
{
  pinMode(relayPin,OUTPUT);
  digitalWrite(relayPin, LOW);
 
  Serial.begin(57600);
  xport.begin(9600);
  xport.print("GET /update?d=B2&s=0 HTTP/1.1\r\nHost: phy-to-phy.appspot.com\r\n\r\n");
  pinMode(ledPin, OUTPUT);
  pinMode(irLedPin, OUTPUT);
  digitalWrite(irLedPin, HIGH);
  //Serial.print("Starting up");
}

void loop()
{
  //Serial.println(analogRead(irDetPin));
  if(analogRead(irDetPin)>850){
    light=0; // impeller blade blocking IR
  }
  else{
    light=1; // impeller blade not blocking IR
  }
 
  if(light != lastLight){
    // edge
    if(millis()-time<minTime){
      // fast edge
      good++;
    }
    else{
      // not fast edge
      good=0;
    }
    time=millis();
    lastLight=light;
  }
 
  if(good>minGoods) {
    // enough good (fast) edges
    digitalWrite(ledPin,HIGH);
    if(millis()-sendTime>100){
      // send a breath, not too fast though
      //Serial.print("I'm sending a breath\n");
      xport.print("GET /update?d=B2&s=1 HTTP/1.1\r\nHost: phy-to-phy.appspot.com\r\n\r\n");
      sendTime = millis();
      }
    }
  else{
    // not enough good (fast) edges
    digitalWrite(ledPin,LOW);
    if(millis()-sendTime>500){
      // send a non-breath, not too fast though
      //Serial.print("I'm sending a non-breath...\n");
      xport.print("GET /update?d=B2&s=0&q=B1 HTTP/1.1\r\nHost: mylameapp.appspot.com\r\n\r\n");
      sendTime = millis();
    
     }
    }
  if(millis() - onTime > 5000){  // timeout after 5 seconds
    digitalWrite(relayPin,LOW);
 }

  while(xport.available()){
         c=(char)xport.read();
         //Serial.print(c);    
         if((c=='B') && (state==0)){state=1;}
         else if((c=='1') && (state==1)){state=2;}
         else if((c==':') && (state==2)){state=3;}
         else if((c=='1') && (state==3)){
           digitalWrite(relayPin,HIGH);
           onTime = millis();
           //Serial.print("REMOTE BREATH!!!\n");
           state=0;
           }
         else if((c=='0') && (state==3)){
           digitalWrite(relayPin,LOW);
           //Serial.print("No remote breath\n");
         }
         else state=0;
      }
}