N K / Mbed 2 deprecated analoghalls5_5

working-est copy with class-based code. still open loop

Dependencies:   mbed

Fork of analoghalls6 by N K

Diff: tempsensors.cpp

Revision:
0:54cf32d35f4d
Child:
1:1f58bdcf2956
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tempsensors.cpp	Sun Mar 01 06:16:01 2015 +0000
@@ -0,0 +1,15 @@
+#include "includes.h"
+#include "classes.h"
+
+NtcTempSensor::NtcTempSensor(PinName pin, float r_25, float ntc_b, float r_divider) {
+    _in = new AnalogIn(pin);
+    _ntc_b = ntc_b;
+    _ntc_a = r_25 / exp(_ntc_b / 298.0f);
+    _r_divider = r_divider;
+}
+
+float NtcTempSensor::GetTemp() {
+    float v = (float) *_in * 3.3f;
+    float r_n = v * _r_divider / (1.0f + v);
+    return _ntc_b / log (r_n / _ntc_a);
+}
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