fix dust sensor serial

src/main.cpp

@@ -89,7 +89,7 @@ RunningAverage geigeraverage(10);
 
 Adafruit_BMP085_Unified bmp = Adafruit_BMP085_Unified(10085);
 DHT dht(DHT22_PIN, DHTTYPE);
-SdsDustSensor sds(SDS_RX, SDS_TX);
+SdsDustSensor sds(SDS_TX, SDS_RX);
 volatile unsigned long geiger_counts = 0;
 unsigned long geiger_previousMillis;
 unsigned long last_dhcp = 0;

src/main.h

@@ -7,6 +7,6 @@
   #define DEBUG_MSG(...)
 #endif
 
-#define FW_VERSION 18
+#define FW_VERSION 20
 
 #endif /* _MAIN_H */