diff --git a/IO_DFPlayer.h b/IO_DFPlayer.h
index 575668b..c60d116 100644
--- a/IO_DFPlayer.h
+++ b/IO_DFPlayer.h
@@ -161,7 +161,7 @@ protected:
     uint8_t pin = vpin - _firstVpin;
  
     // Validate parameter.
-    volume = min(30,volume);
+    volume = min((uint8_t)30,volume);
 
     if (pin == 0) {
       // Play track 
diff --git a/IO_HCSR04.h b/IO_HCSR04.h
index d56dda3..e7b5622 100644
--- a/IO_HCSR04.h
+++ b/IO_HCSR04.h
@@ -138,7 +138,7 @@ private:
   //
   void read_HCSR04device() {
     // uint16 enough to time up to 65ms
-    uint16_t startTime, waitTime, currentTime, maxTime;  
+    uint16_t startTime, waitTime = 0, currentTime, maxTime;  
 
     // If receive pin is still set on from previous call, abort the read.
     if (ArduinoPins::fastReadDigital(_echoPin))
@@ -186,4 +186,4 @@ private:
 
 };
 
-#endif //IO_HCSR04_H
\ No newline at end of file
+#endif //IO_HCSR04_H