Revision 3:b3153fd49501, committed 2015-03-26

Comitter:

sitakumar

Date:

Thu Mar 26 18:05:13 2015 +0000

Parent:

2:f266f102ca80

Commit message:

This program takes a calibration when a button is pressed, takes the measurement and then sends pH and temp values through BLE. 3/26/15

Changed in this revision

--- a/main.cpp	Sat Mar 21 17:48:29 2015 +0000
+++ b/main.cpp	Thu Mar 26 18:05:13 2015 +0000
@@ -1,20 +1,105 @@
 #include "mbed.h"
-//#include "DebounceIn.h"
 #include "BLEPeripheral.h"
- 
+
+//serial connection via USB 
 Serial serial(USBTX, USBRX);
- 
+
+//Declare Input and Output pins
+DigitalIn pb(D3);
+AnalogIn pH_sensor(A0);
+DigitalIn cb(D2); 
+DigitalOut led(LED_RED);
+
 // The SPI construct, REQN and RDYN IO construct should be modified manually
 // It depend on the board you are using and the REQN&RDYN configuration on BLE Shield
 SPI spi(PTD2, PTD3, PTD1);      
 DigitalInOut BLE_RDY(PTD5);  
 DigitalInOut BLE_REQ(PTD0); 
-DigitalInOut BLE_RESET(PTA13); 
-DigitalIn pb(D4);
+DigitalInOut BLE_RESET(PTA13);
+
+//for BLE
 int count = 0;
 unsigned char txbuf[16] = {0};
 unsigned char txlen = 0;
- 
+
+//for pH measurement
+float calib = 0;
+float avgReading = 0;
+
+//This loop takes a reading by taking 15 measurements and averaging them when it is called in the loop "measure"
+int takeReading()
+{
+    double totalVal = 0.0;
+    double pH_sensor_read = 0.0;
+    int totalReadings = 0;
+    while(totalReadings < 16){
+        pH_sensor_read = pH_sensor.read();
+        totalVal = totalVal + pH_sensor_read;
+        totalReadings++;
+        }
+    float avgSensor = totalVal/15;      
+    if (avgSensor > 0.3)
+    {
+        led = 1;
+    }
+    return avgSensor;
+ }
+
+int* measure()
+{
+    serial.baud(115200);
+    serial.printf("start");
+    float voltage, pH, tempC, tempF,loopnumber,yint;
+    cb.mode(PullUp);
+    led = 0;
+    loopnumber = 1;
+    
+//Loop to run calibration value 
+    while(loopnumber==1) 
+    {
+          if(!cb)
+          {
+                serial.printf("calib is %f\n", calib);
+                calib = takeReading();
+                serial.printf("calib is %d\n", calib);
+                loopnumber = 2;
+          }
+    }
+        
+//Loop to take measurement        
+    while(loopnumber==2) 
+    {
+        serial.printf("enter new loop\n");
+        serial.printf("calib is %d\n", calib);
+        //Take average of readings over 10 seconds
+        avgReading = takeReading();
+        //Hard coded calibration values taken at pH 4 solution to return voltage in mV
+        //.24 is the pin read out at pH4
+        //800 is mV at ph4
+        //voltage = avgReading*(800/.24);  
+        
+        //trying to get voltage straight from MicroController -- this command does not work
+        //voltage = ADC_GetConversionValue(pH_sensor);
+        
+        //conversion to pH from sensor output voltage per LM61 data sheet
+        //pH = (0.0209*voltage)-12.696;
+        
+        //calcuating yintercept of the ADC -> pH equation using calibration value and given that calibration liquid is pH4
+        yint = (68.97*calib)-4;
+        serial.printf("yint is %f", yint);
+        //assumes linear relationship between pin readout -> voltage ->pH
+        pH = (0.0209*3300)*(avgReading)-yint;
+        //conversion to degrees C from sensor output voltage
+        tempC = (((voltage/1000) - 1.022129)/-0.0018496);
+        tempF = (tempC *9/5) + 32;
+        //print current pH and temp
+        serial.printf("pH = %5.2F & temp = %5.2F F\n\r", pH, tempF);           
+    }
+    int pHtemparray[] = {pH,tempF};
+    return pHtemparray;
+}
+
+
 /*----- BLE Utility -------------------------------------------------------------------------*/
 // create peripheral instance, see pinouts above
 BLEPeripheral            blePeripheral        = BLEPeripheral(&BLE_REQ, &BLE_RDY, NULL);
@@ -32,61 +117,51 @@
  
 int main()
 { 
+    
+    pb.mode(PullUp);
+    serial.baud(115200);
     serial.printf("Hello SmartD!\n");
-    //serial.baud(115200);
     serial.printf("Serial begin!\r\n");
-    
- pb.mode(PullUp);
-     wait(.001);
-
+    void begin();
+ 
      /*----- BLE Utility ---------------------------------------------*/
     // set advertised local name and service UUID
     blePeripheral.setLocalName("Sita");
     
     blePeripheral.setAdvertisedServiceUuid(uartService.uuid());
-    
+        
     // add service and characteristic
     blePeripheral.addAttribute(uartService);
     blePeripheral.addAttribute(rxCharacteristic);
     blePeripheral.addAttribute(txCharacteristic);
-    
+
     // begin initialization
     blePeripheral.begin();
     /*---------------------------------------------------------------*/
     
     serial.printf("BLE UART Peripheral begin!\r\n");
-    
+    int* reading = measure();
+    serial.printf("pH is %d, Temp is %d\n\r", reading[0], reading[1]);
     while(1)
     {
         BLECentral central = blePeripheral.central();
-        
         if (central) 
         {
             // central connected to peripheral
             serial.printf("Connected to central\r\n");
             while (central.connected()) 
             {
-                // central still connected to peripheral
-                if (!pb) 
+                if (!pb)  // if button pushed
                 {
-                  count++;
-                  wait(.5);
-                  //serial.printf("%d",count);
+                    // Read and send out pH value from measure function
+                    unsigned short value = reading[0];
+                    const unsigned char val[1] = {value};
+                    txCharacteristic.setValue(val,1);
                 }
-                if(count>0)
-                {serial.printf("button pressed\r\n");
-                count = 0;
-                wait (.5);}                           
             }
-        }
         
             // central disconnected
-        else 
-        {
             serial.printf("Disconnected from central\r\n");
         }
-        }
     }
-
-
-      
\ No newline at end of file
+}
\ No newline at end of file