diff --git a/bot.py b/bot.py
index cb2d7fe..b699f1f 100644
--- a/bot.py
+++ b/bot.py
@@ -12,6 +12,7 @@ import cv2
 import numpy as np
 import telegram
 from aiohttp import BasicAuth
+from cv2 import aruco
 from pytapo import Tapo
 from telegram import Update, Message
 from telegram.ext import Updater
@@ -94,8 +95,8 @@ class Bot:
         # Iterate until we find all 4 aruco markers or timeout
         aruco_corners = {}
         annotated_image = None
-        aruco_dict = a.getPredefinedDictionary(a.DICT_6X6_250)
-        aruco_params = a.DetectorParameters()
+        aruco_dict = aruco.getPredefinedDictionary(aruco.DICT_6X6_250)
+        aruco_params = aruco.DetectorParameters()
 
         t0 = time.time()
         print("Taking image with ArUco markers...")
@@ -121,11 +122,12 @@ class Bot:
                 continue
 
             # Detect the markers
-            corners, ids, rejected = a.detectMarkers(
+            corners, ids, rejected = aruco.detectMarkers(
                 annotated_image, aruco_dict, parameters=aruco_params
             )
-            for corner, i in zip(corners, ids):
-                aruco_corners[i[0]] = corner
+            if corners is not None and ids is not None:
+                for corner, i in zip(corners, ids):
+                    aruco_corners[i[0]] = corner
         assert annotated_image is not None
 
         del vcap
@@ -138,7 +140,7 @@ class Bot:
 
         corners = [aruco_corners[i] for i in range(1, 5)]
         ids = np.array([[i] for i in range(1, 5)])
-        a.drawDetectedMarkers(annotated_image, corners, ids)
+        aruco.drawDetectedMarkers(annotated_image, corners, ids)
 
         # Annotate the image with the detected markers and apply the perspective transform to the pretty image