diff --git a/PerceivedObject.h b/PerceivedObject.h
index 1f6f556..5b97ba3 100644
--- a/PerceivedObject.h
+++ b/PerceivedObject.h
@@ -18,9 +18,10 @@ public:
   float radius;
   Sensor *sensor = nullptr;
 
-  static constexpr char maxConfidence = 255;
-  static constexpr char confidenceDropSpeed = 2;
-  char confidence;
+  static constexpr unsigned char maxConfidence = 255;
+  static constexpr unsigned char confidenceDropSpeed = 2;
+  unsigned char confidence;
+
   bool DegradeConfidence(float deltaTime);
   void Refresh(Polar position, float radius);
 };