disable example codes for calculating ppm

diff --git a/src/co2-sensor.c b/src/co2-sensor.c
index 11973c3..5c58667 100644 (file)
--- a/src/co2-sensor.c
+++ b/src/co2-sensor.c
@@ -26,17 +26,19 @@
 #define CO2_SENSOR_REF_VOLTAGE (5)
 #define CO2_SENSOR_VALUE_MAX (1024)
 
+//#define USE_EXAMPLE_CODE
+
+#ifdef USE_EXAMPLE_CODE
 /* CAUTION !!  These data are EXAMPLE Data, NOT REAL data */
 #define CO2_SENSOR_DEFAULT_VALUE_ZP (690) // 400ppm
 #define CO2_SENSOR_DEFAULT_VALUE_1000 (600)
-
-#define USE_EXAMPLE_CODE
+#endif /* USE_EXAMPLE_CODE */
 
 static const double log400 = 2.602;
 
 static bool initialized = false;
 static double co2_zp_volt = -1;
-static double slope_value = 10000;
+static double slope_value = 10000; // A real slope value should be a negative value.
 
 void co2_sensor_close(void)
 {
@@ -117,7 +119,7 @@ unsigned int co2_sensor_voltage_to_ppm(double voltage)
        ppm = pow(10, (voltage - co2_zp_volt)/slope_value + log400);
 //     if (ppm > 10000)
 //             ppm = 10000;
-#endif
+#endif /* USE_EXAMPLE_CODE */
 
        return (unsigned int)ppm;
 }