diff --git a/src/interval.cpp b/src/interval.cpp
index 0f32daf..64972b1 100644
--- a/src/interval.cpp
+++ b/src/interval.cpp
@@ -24,7 +24,7 @@ bool Interval::expired(void)
   bool result = false;
   if (_done)
   {
-    if (1 == mode)
+    if (1 == _mode)
     { // oneshot mode
       if ((millis() - _timefrom) >= _timeout)
       {
@@ -32,7 +32,7 @@ bool Interval::expired(void)
         result = true;
       }
     }
-    else if (2 == mode)
+    else if (2 == _mode)
     { // periodic mode
       if ((millis() - _timefrom) >= _timeout)
       {