Diff: TemperatureSensor.cpp

Revision:

0:6dee052a3fa4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TemperatureSensor.cpp	Tue Jul 26 05:30:53 2011 +0000
@@ -0,0 +1,34 @@
+#include <TemperatureSensor.h>
+#include <math.h>
+
+TemperatureSensor::TemperatureSensor():adc(p20) {
+    percentOfScale= adc.read();
+}
+
+void TemperatureSensor::measure(void) {
+    static const float R= 10500.0;
+    static const float LP= 0.01;
+    
+    percentOfScale= ((1.0 - LP) * percentOfScale) + (LP * adc.read());
+    resistance= (percentOfScale * R) / (1.0 - percentOfScale);
+}
+
+float TemperatureSensor::getKelvin(void) {
+    float x;
+
+    // Compute the Steinhard-Hart eqn:  1/t = A + B*ln(r) + C*ln(r)^3 + D*ln(r)^5
+    static const float A= 1.006389097E-3;
+    static const float B= 2.425678347E-4;
+    static const float C= 1.452612422E-7;
+
+    x= log(resistance);
+    return 1.0 / (A + (B * x) + (C * x * x * x));
+}
+
+float TemperatureSensor::getResistance(void) {
+    return resistance;
+}
+
+float TemperatureSensor::getPercentOfScale(void) {
+    return percentOfScale;
+}
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