Diff: main.cpp

Revision:

0:83dfc83e48bf

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Nov 06 07:31:40 2013 +0000
@@ -0,0 +1,65 @@
+#include "mbed.h"
+
+DigitalOut myled(LED1);
+Serial pc(USBTX, USBRX);
+AnalogIn tempPin(p15);
+
+float tempTotal;
+uint32_t tempDiv;
+
+#define MAX_TEMP_AVG 10
+
+void sampleTemperature();
+void sampleTemperatures();
+void resetTemperatureSamples();
+float getAvgTemperature();
+
+void sampleTemperature()
+{
+        tempTotal += tempPin; //we use 3.3V from VOUT
+        tempDiv++;
+}
+
+void sampleTemperatures()
+{
+    for(int i=0;i<MAX_TEMP_AVG;i++) {
+        sampleTemperature();
+        wait(0.1);
+    }
+}
+
+void resetTemperatureSamples()
+{
+    tempTotal = 0.0;
+    tempDiv = 0;
+}
+float getAvgTemperature()
+{
+    /* Temperature calculations is (VOut - V0)/Tc 
+    * VOut = V out from sensor
+    * V0 = Voltage on 0 Celcius, 500mv for MCP9700
+    * Tc = Temperatur constant, 10mV/C
+    */
+    float tempAvg = (((tempTotal*3300)/(float)tempDiv)-500.0)/10.0;
+    return tempAvg;
+}
+
+int main() {
+tempDiv = 0;
+    pc.printf("MBED ready..\r\n");
+    sampleTemperatures();
+    pc.printf("Temp: %.2f.\r\n",getAvgTemperature());
+    while(1) {
+        sampleTemperature();
+        
+        myled = 1;
+        wait(0.5);
+        myled = 0;
+        wait(0.5);
+        
+        if (tempDiv > MAX_TEMP_AVG) {
+            pc.printf("Temp: %.2f.\r\n",getAvgTemperature());
+            resetTemperatureSamples();
+        }
+    }
+}