diff --git a/src/common/math.c b/src/common/math.c
index a1743ab..e6a2a07 100644
--- a/src/common/math.c
+++ b/src/common/math.c
@@ -10,16 +10,19 @@
 // TODO: Is resistance function semantically correct?
 // TODO: Check results for humidity conversion functions.
 
+// Thermistor general constants
+#define R1    10000.0f  // Resistor ohm value
+#define VRES  0xFFFF    // 16-bit ADC resolution
+
 // Thermistor coeficients
-static const float SC1 = 1.009249522e-3f;
-static const float SC2 = 2.378405444e-4f;
-static const float SC3 = 2.019202697e-7f;
-static const float R1  = 10000.0f;
+#define SC1  1.009249522e-3f
+#define SC2  2.378405444e-4f
+#define SC3  2.019202697e-7f
 
 // Humidity conversion constants
-static const float TH1 = 100.0f;
-static const float TH2 = 243.04f;
-static const float TH3 = 17.625f;
+#define TH1  100.0f
+#define TH2  243.04f
+#define TH3  17.625f
 
 float Resistance(int adc_raw)
 {
@@ -30,10 +33,9 @@ float Resistance(int adc_raw)
 
 	// [GND] - [10K RESISTOR] - [ADC INPUT] - [THERMISTOR] - [VCC]
 
+	// return ((VRES - adc_raw) * R1) / adc_raw;
 	r2 = (float) adc_raw / 264.8f * 0.05f;
 
-	// XXX: Ohms Law solved for resistance?
-	//          R = V / I
 	return R1 / (5.0f / r2 - 1.0f);
 }