diff --git a/filter/bs412.h b/filter/bs412.h
index 8367b4a..82b212d 100644
--- a/filter/bs412.h
+++ b/filter/bs412.h
@@ -7,6 +7,7 @@
 #include <math.h>
 #include <string.h>
 #include <stdint.h>
+#include <stdbool.h>
 #ifdef BS412_DEBUG
 #include "../lib/debug.h"
 #endif