diff --git a/robot/arlo.py b/robot/arlo.py
index c9ae130..3a01b72 100644
--- a/robot/arlo.py
+++ b/robot/arlo.py
@@ -106,7 +106,7 @@ class Arlo():
         # return (FOCAL_LENGTH * 14.5)/avg_size
 
         return cv2.aruco.estimatePoseSingleMarkers(
-            [bounding_box], 14.5, CAMERA_MATRIX, DIST_COEF
+            np.array([bounding_box]), 14.5, CAMERA_MATRIX, DIST_COEF
         )
 
     def find_aruco(self, image):