Revision 1:ab9f0e572c98, committed 2020-08-27

Comitter:

f3d

Date:

Thu Aug 27 12:42:55 2020 +0000

Parent:

0:6d4b6c56a7ad

Commit message:

Initial commit

Changed in this revision

diff -r 6d4b6c56a7ad -r ab9f0e572c98 UVSensor.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/UVSensor.h	Thu Aug 27 12:42:55 2020 +0000
@@ -0,0 +1,51 @@
+#ifndef __UVSENSOR_H
+#define __UVSENSOR_H
+#include <mbed.h>
+#include <BLE.h>
+AnalogIn UVSignalIn(P0_28);
+
+class UVService {
+public:
+    const static uint16_t UV_SERVICE_UUID = 0xA012;
+    const static uint16_t UV_CHARACTERISTIC_UUID = 0xA013;
+    
+    UVService(BLE &_ble, int16_t initialUVValue) :
+        ble(_ble), UVValue(UV_CHARACTERISTIC_UUID, &initialUVValue)
+    {
+        GattCharacteristic *charTable[] = {&UVValue};
+        GattService uvservice(UV_SERVICE_UUID, charTable, sizeof(charTable) / sizeof(GattCharacteristic *));
+        ble.addService(uvservice);      
+    }
+
+    GattAttribute::Handle_t getValueHandle() const {
+        return UVValue.getValueHandle();
+    }
+    void updateUVValue(uint16_t newValue) {
+        ble.gattServer().write(UVValue.getValueHandle(), (uint8_t *)&newValue, sizeof(uint16_t));
+    }
+
+    void poll()
+    {       
+        uint16_t ADCIn = UVSignalIn.read_u16();
+        // Need to scale this to mW/cm^2
+        // To convert to a voltage : * 3.6/4095
+        // To convert voltage to mW/cm^2 see page 8 of datasheet for ML8511 sensor
+        // This graph is for 3.0V, but the supply in this example is 3.3V. 
+        // I'm ASSUMING that the device output is not a function of voltage supply (within reason)
+        // From Graph : UV power / area is roughly given by:
+        // Power = (Voltage - 1) * 7; 
+        // Need to avoid unsigned overflow
+        // An input of 1V should give an ADC Value of (1/3.6)*4095 = 1137.5 (1138)
+        if (ADCIn >= 1137 )
+            ADCIn = ADCIn - 1137;
+        else
+            ADCIn = 0;
+        ADCIn = ADCIn  / 163; // 4095 / (7*3.6) = 163                   
+        updateUVValue(ADCIn);                
+    }
+private:
+    BLE &ble;
+    ReadOnlyGattCharacteristic<int16_t>  UVValue;
+
+};
+#endif
\ No newline at end of file

diff -r 6d4b6c56a7ad -r ab9f0e572c98 main.cpp
--- a/main.cpp	Sat Aug 22 15:21:53 2020 +0000
+++ b/main.cpp	Thu Aug 27 12:42:55 2020 +0000
@@ -15,22 +15,25 @@
  */
 
 #include "mbed.h"
+#include "UVSensor.h"
 
-#include "ble/services/iBeacon.h"
+#include <BLE.h>
 
 BLE ble;
+
 const static char     DEVICE_NAME[] = "NRF52832";
-static const uint16_t uuid16_list[] = {0xabcd,0x1234};    
+static const uint16_t uuid16_list[] = {UVService::UV_SERVICE_UUID};    
 DigitalOut Led(P0_25);
 Ticker ticker;
+UVService *UVServicePtr;
 void periodicCallback(void)
 {
       
+    UVServicePtr->poll();
     if (Led == 0)
         Led = 1;
     else
         Led = 0;
-            
 }
 
 /**
@@ -81,6 +84,8 @@
     ble.gap().onDisconnection(disconnectionCallback);
     ble.gattServer().onDataWritten(onDataWrittenCallback);
     ble.gattServer().onDataRead(onDataReadCallback); 
+    uint16_t initial_value = 0;
+    UVServicePtr = new UVService(ble,initial_value);
 
     /* setup advertising */
     ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED | GapAdvertisingData::LE_GENERAL_DISCOVERABLE);
@@ -92,12 +97,11 @@
 }
 int main(void)
 {
-    ticker.attach(periodicCallback, 0.1); /* Poll devices every 100ms */
-    ble.init(bleInitComplete);
-    
+    ble.init(bleInitComplete);    
     /* SpinWait for initialization to complete. This is necessary because the
      * BLE object is used in the main loop below. */
     while (!ble.hasInitialized()) { /* spin loop */ }  
+    ticker.attach(periodicCallback, 0.1); /* Poll devices every 100ms */
     while (true) {
         ble.waitForEvent(); // allows or low power operation            
     }