Diff: sensors/SMTC502AT.cpp

Revision:

0:846e2321c637

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sensors/SMTC502AT.cpp	Fri Apr 13 04:19:23 2018 +0000
@@ -0,0 +1,47 @@
+#include "mbed.h"
+#include "SMTC502AT.h"
+
+SMTC502AT::SMTC502AT(AnalogIn *ain, float R0, float R1, float B, float T0) 
+{
+    _ain = ain ;
+    _r0 = R0 ;
+    _r1 = R1 ;
+    _b  = B ;
+    _t0 = T0 ;
+}
+
+SMTC502AT::~SMTC502AT(void)
+{
+    if (_ain) {
+        delete _ain ;
+    }
+}
+
+/**
+ * getTemp returns the temperature
+ * operational temperature is -50C to +105C
+ */
+float SMTC502AT::getTemp(void)
+{
+    float result = 0.0 ;
+    float f, raw, rr1, t ;
+    if (_ain) {
+        f = _ain->read() ;
+#if 0
+        if (f < 0.087) { /* +105C */
+            printf("Temp is Too high or the sensor is absent\n") ;
+            f = 0.087 ;
+        }
+        if (f > 0.978) { /* -50C */
+            printf("Temp is Too low or the sensor encountered a problem\n") ;
+            f = 0.978 ;
+        }
+#endif
+        raw = f * 3.3 ;
+        rr1 = _r1 * raw / (3.3 - raw) ;
+        t = 1.0 / (log(rr1 / _r0) / _b + (1/_t0)) ;
+        result = t - 273.15 ;
+    }
+    return( result ) ;
+}
+        
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