diff --git a/code.cpp b/code.cpp
index 2911d13..7bfad5d 100644
--- a/code.cpp
+++ b/code.cpp
@@ -22,7 +22,7 @@ unsigned long lastUpdateTime  = 0;
 /*
  * Amount of spark fires in a single interval
  */
-int sparkFireCount            = 0;
+volatile int sparkFireCount            = 0;
 
 /*
  * Rpm value from last update
@@ -123,4 +123,4 @@ void loop() {
     lastUpdateTime = millis();
     lastRpmValue = currentRpm;
   }
-}
\ No newline at end of file
+}