Diff: victimBreath.cpp

Revision:

0:031f7beccd55

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/victimBreath.cpp	Thu Nov 24 19:32:41 2016 +0000
@@ -0,0 +1,59 @@
+#include "victimBreath.h"
+#include "mbed.h"
+
+AnalogIn windSensor(p17);
+DigitalOut myLED(LED1);
+Ticker breathReader;
+
+volatile float thresh = windSensor*1.4;
+//volatile bool Breath = false;     // set on each visit to interrupt routine
+volatile bool isBreathing = false;
+volatile int breathCount = 0; //increment if breath is above thresh on each visit to interrupt routine
+
+victimBreath :: victimBreath(){
+    }
+    
+void victimBreath :: startReading(){
+    breathReader.attach(this, &victimBreath::sample, .002f);
+    //volatile float a = windSensor;
+    //printf("\nwindsensor reads: %f", a);
+    //printf("\nthresh is: %f", thresh);
+}
+
+void victimBreath :: stopReading(){
+    breathReader.detach();
+    __enable_irq();
+}
+
+void victimBreath :: reset() {        
+    //thresh = windSensor*1.2; //set thresh to an appropraite percent above the baseline reading
+    //Breath = false;     // true victims breath crosses thresh
+    isBreathing = false; //true if we get 3 'Breaths' in the calling programs time window-->means victim is breathing
+    breathCount = 0;       
+}
+
+//call this member function to see if victim is breathing
+bool victimBreath :: breathDetected() {
+    return isBreathing; //only return positive if we get the critical number of Breaths in the given time window
+}
+
+
+// THIS IS THE TIMER 2 INTERRUPT SERVICE ROUTINE. 
+// Timer 2 makes sure that we take a reading every 2 miliseconds
+void victimBreath :: sample() {                         // triggered when Timer2 counts to 124
+  __disable_irq();            
+  float readVal = windSensor;                          // sample
+  
+
+    //check to see if victim is breathing at all above natural variation in sensor noise
+  if(readVal >= thresh){       
+      breathCount++;                         //increment global counter
+    }
+  if(breathCount >= 3){ //should set this higher if want more certainty in victim breathing
+      isBreathing = true;
+  }
+  __enable_irq();                               // enable interrupts again
+        //return; 
+}
+
+  
\ No newline at end of file