MDM9206 with Heart Rate Sensor

gagentMain---->sensorInit----->led_init---->Pulsesensor_init.
  demo-Smart-Heart-rate-detector/main/main.c
  void gagentMain(void)
  {
    getFreeHeap();
    sensorInit();
    gizwitsInit();
    timer_init();
    timer_start();
  }

void sensorInit(void)
  {
    gizLog(LOG_INFO, "Sensor initialization ...\n");
    led_init();
    Pulsesensor_init();
  }
  
  void led_init()
  {
    gizLog(LOG_INFO, "in led init...\n");
    led_gpio_config();
    led_on_off(false, led_red);
  }
  void Pulsesensor_init()
  {
    qapi_Status_t status = QAPI_ERROR;
    const char *Channel_Name_ADC0 = ADC_INPUT_ADC0;
    qapi_Timer_Sleep(2, QAPI_TIMER_UNIT_SEC, true);
    status = adc_open_handle();  
    if(status != QAPI_OK)
      {
      //IOT_DEBUG("Get ADC Handle ERROR!");
      gizLog(LOG_INFO,"adc open handle error...\n");
      return;
      }
    status = adc_get_properties(Channel_Name_ADC0, &Properties_ADC0);
      if(status != QAPI_OK)
      {
      //IOT_DEBUG("Get ADC channel-%s Configuration ERROR!", Channel_Name_ADC1);
      gizLog(LOG_INFO,"Get ADC channel-%s Configuration ERROR...\n", Channel_Name_ADC0);
      return;
      }
  }
  demo-Smart-Heart-rate-detector/driver/timer/timer.c
  qapi_Status_t timer_init(void)      //init 
  {
              qapi_Status_t status = QAPI_OK;
              memset(&timer_def_attr, 0, sizeof(timer_def_attr));
    timer_def_attr.cb_type	= QAPI_TIMER_FUNC1_CB_TYPE;
    timer_def_attr.deferrable = false;
    timer_def_attr.sigs_func_ptr = timer1_handler;
    timer_def_attr.sigs_mask_data = 0x11;
    status = qapi_Timer_Def(&timer_handle, &timer_def_attr);
              return status;
  }
  qapi_Status_t timer_start(void)
  {
      qapi_Status_t status = QAPI_OK;
  
              memset(&timer_set_attr, 0, sizeof(timer_set_attr));
    timer_set_attr.reload = 100;
    timer_set_attr.time = 10;
    timer_set_attr.unit = QAPI_TIMER_UNIT_MSEC;
    status = qapi_Timer_Set(timer_handle, &timer_set_attr);
              return status;
  }
  void timer1_handler(uint32_t data)         // timer callback
  {
    static bool led_red_status = true;
    getHeartRateValue(&heartrate);            //get heartvalue
    if(!heartrate)	                                       //no  value		
    {
      return;
    }
    else if(((heartrate > HEART_RATE_THRESHOLD_HIGH) || (heartrate < HEART_RATE_THRESHOLD_LOW)))	  // value is not vaild
    {
      led_on_off(true, led_red);	      //red on
      //led_on_off(led_red_status, led_red);		
      //led_red_status = !led_red_status;
    }
      else					      // value is vaild
    {
      led_on_off(false,led_red);		//red off
    } 
  }
  
  demo-Smart-Heart-rate-detector/driver/plusensor/plusensor.c
  
  uint8_t getHeartRateValue(uint32_t* heartrate )	//Algorithm implementation for calculating heart rate	
  {
    gizLog(LOG_INFO,"in getHeartRateValue...\n");	
    .......
    memset(&result, 0, sizeof(result));
    status = qapi_ADC_Read_Channel(adc_handle, &Properties_ADC0, &result);   // read the Pulse Sensor
              ........
    sampleCounter += 10;  // keep track of the time in mS with this variable
    Num = sampleCounter - lastBeatTime;    // monitor the time since the last beat to avoid noise
    //  find the peak and trough of the pulse wave
    if(Signal < thresh && Num > (IBI/5)*3)   // avoid dichrotic noise by waiting 3/5 of last IBI
    {  
      if(Signal < T)		// T is the trough	
      {                       
        T = Signal;                      						            // keep track of lowest point in pulse wave 
        gizLog(LOG_INFO,"Find trough, T = %d\n", T);
      }
    }
    if(Signal > thresh && Signal > P)		// thresh condition helps avoid noise
    {          
      P = Signal;                             // P is the peak,keep track of highest point in pulse wave
      gizLog(LOG_INFO,"Find peak, P = %d\n", P);
    }                                        
    //  NOW IT'S TIME TO LOOK FOR THE HEART BEAT		
    // signal surges up in value every time there is a pulse
    if (Num > 600)			
    {                                   // avoid high frequency noise	
      if ( (Signal > thresh) && (Pulse == false) && (Num > (IBI/5)*3) )
      {        
        Pulse = true;        // set the Pulse flag when we think there is a pulse
        IBI = sampleCounter - lastBeatTime;         // measure time between beats in mS
        lastBeatTime = sampleCounter;               // keep track of time for next pulse
        if(secondBeat)	                  // if this is the second beat, if secondBeat == TRUE
        {                        
          secondBeat = false;   // clear secondBeat flag
          for(int i=0; i<=9; i++)
          {             
            rate[i] = IBI;     	// seed the running total to get a realisitic BPM at startup                 
          }
        }
        if(firstBeat)           // if it's the first time we found a beat, if firstBeat == TRUE
        {                         
        firstBeat = false;          // clear firstBeat flag
        secondBeat = true;        // set the second beat flag
        return 0;                          // IBI value is unreliable so discard it
        }   
  
        // keep a running total of the last 10 IBI values
        runningTotal = 0;             // clear the runningTotal variable 
        for(int i=0; i<=8; i++)	
        {                
          rate[i] = rate[i+1];           // shift data in the rate array       		 	
  // and drop the oldest IBI value 
          runningTotal += rate[i];          // add up the 9 oldest IBI values
        }
        rate[9] = IBI;                          		// add the latest IBI to the rate array
        runningTotal += rate[9];               	 // add the latest IBI to runningTotal
        runningTotal /= 10;                     	// average the last 10 IBI values 
        BPM = 60000/runningTotal;        	 // how many beats can fit into a minute? that's BPM!
        *heartrate = BPM;
        gizLog(LOG_INFO,"BPM = %d\n", *heartrate); 
        QS = true;                            					 // set Quantified Self flag 
          // QS FLAG IS NOT CLEARED INSIDE THIS ISR
      }                       
    }
  
    if (Signal < thresh && Pulse == true)
    {   // when the values are going down, the beat is over
      Pulse = false;                         // reset the Pulse flag so we can do it again
      amp = P - T;                           // get amplitude of the pulse wave
      thresh = amp/2 + T;                    // set thresh at 50% of the amplitude
      P = thresh;                            // reset these for next time
      T = thresh;
    }
    if (Num > 2500)
    {                           // if 2.5 seconds go by without a beat
      thresh = 512;                          // set thresh default
      P = 512;                               // set P default
      T = 512;                               // set T default
      lastBeatTime = sampleCounter;          // bring the lastBeatTime up to date        
      firstBeat = true;                      // set these to avoid noise
      secondBeat = false;                    // when we get the heartbeat back
    }
  }