diff --git a/config.def.h b/config.def.h
index 6c42e0a..9dcd5d6 100644
--- a/config.def.h
+++ b/config.def.h
@@ -1,7 +1,7 @@
 /* See LICENSE file for copyright and license details. */
 
 /* interval between updates (in ms) */
-static const int interval = 1000;
+static const unsigned int interval = 1000;
 
 /* text to show if no value can be retrieved */
 static const char unknown_str[] = "n/a";