diff --git a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_config.h b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_config.h
index deb3028..2949d6e 100644
--- a/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_config.h
+++ b/firmware/AVR-Source/Pyr0_Piezo_Sensor_v2.x.x/src/pP_config.h
@@ -47,7 +47,7 @@
  extern int Debug;
 #endif
 
-#if !(defined(voldMeterConstant))
+#if !(defined(voltMeterConstant))
   extern long voltMeterConstant = 1125300L; // For fine tuning input voltage sense
 #endif