diff --git a/lerobot/common/envs/factory.py b/lerobot/common/envs/factory.py
index d73939b1..c39b6e09 100644
--- a/lerobot/common/envs/factory.py
+++ b/lerobot/common/envs/factory.py
@@ -19,7 +19,7 @@ import gymnasium as gym
 from omegaconf import DictConfig
 
 
-def make_env(cfg: DictConfig, n_envs: int | None = None) -> gym.vector.VectorEnv:
+def make_env(cfg: DictConfig, n_envs: int | None = None) -> gym.vector.VectorEnv | None:
     """Makes a gym vector environment according to the evaluation config.
 
     n_envs can be used to override eval.batch_size in the configuration. Must be at least 1.
@@ -27,6 +27,9 @@ def make_env(cfg: DictConfig, n_envs: int | None = None) -> gym.vector.VectorEnv
     if n_envs is not None and n_envs < 1:
         raise ValueError("`n_envs must be at least 1")
 
+    if cfg.env.name == "real_world":
+        return    
+
     package_name = f"gym_{cfg.env.name}"
 
     try:
diff --git a/lerobot/common/robot_devices/cameras/opencv.py b/lerobot/common/robot_devices/cameras/opencv.py
index eca306e6..6b11eec1 100644
--- a/lerobot/common/robot_devices/cameras/opencv.py
+++ b/lerobot/common/robot_devices/cameras/opencv.py
@@ -1,5 +1,6 @@
 import argparse
 import math
+import threading
 import time
 from dataclasses import dataclass, replace
 from pathlib import Path
@@ -8,9 +9,8 @@ from threading import Thread
 import cv2
 
 from lerobot.common.robot_devices.utils import RobotDeviceAlreadyConnectedError, RobotDeviceNotConnectedError
-# Using 1 thread to avoid blocking the main thread.
-# Especially useful during data collection when other threads are used
-# to save the images.
+# Use 1 thread to avoid blocking the main thread. Especially useful during data collection
+# when other threads are used to save the images.
 cv2.setNumThreads(1)
 import numpy as np
 
@@ -89,6 +89,10 @@ class OpenCVCameraConfig:
     height: int | None = None
     color: str = "rgb"
 
+    def __post_init__(self):
+        if self.color not in ["rgb", "bgr"]:
+            raise ValueError(f"Expected color values are 'rgb' or 'bgr', but {self.color} is provided.")
+
 
 class OpenCVCamera:
     # TODO(rcadene): improve dosctring
@@ -122,12 +126,10 @@ class OpenCVCamera:
         if not isinstance(self.camera_index, int):
             raise ValueError(f"Camera index must be provided as an int, but {self.camera_index} was given instead.")
 
-        if self.color not in ["rgb", "bgr"]:
-            raise ValueError(f"Expected color values are 'rgb' or 'bgr', but {self.color} is provided.")
-
         self.camera = None
         self.is_connected = False
         self.thread = None
+        self.stop_event = None
         self.color_image = None
         self.logs = {}
 
@@ -159,26 +161,26 @@ class OpenCVCamera:
         # needs to be re-created.
         self.camera = cv2.VideoCapture(self.camera_index)
 
-        if self.fps:
+        if self.fps is not None:
             self.camera.set(cv2.CAP_PROP_FPS, self.fps)
-        if self.width:
+        if self.width is not None:
             self.camera.set(cv2.CAP_PROP_FRAME_WIDTH, self.width)
-        if self.height:
+        if self.height is not None:
             self.camera.set(cv2.CAP_PROP_FRAME_HEIGHT, self.height)
 
         actual_fps = self.camera.get(cv2.CAP_PROP_FPS)
         actual_width = self.camera.get(cv2.CAP_PROP_FRAME_WIDTH)
         actual_height = self.camera.get(cv2.CAP_PROP_FRAME_HEIGHT)
 
-        if self.fps and not math.isclose(self.fps, actual_fps, rel_tol=1e-3):
+        if self.fps is not None and not math.isclose(self.fps, actual_fps, rel_tol=1e-3):
             raise OSError(
                 f"Can't set {self.fps=} for camera {self.camera_index}. Actual value is {actual_fps}."
             )
-        if self.width and self.width != actual_width:
+        if self.width is not None and self.width != actual_width:
             raise OSError(
                 f"Can't set {self.width=} for camera {self.camera_index}. Actual value is {actual_width}."
             )
-        if self.height and self.height != actual_height:
+        if self.height is not None and self.height != actual_height:
             raise OSError(
                 f"Can't set {self.height=} for camera {self.camera_index}. Actual value is {actual_height}."
             )
@@ -216,6 +218,10 @@ class OpenCVCamera:
         if requested_color == "rgb":
             color_image = cv2.cvtColor(color_image, cv2.COLOR_BGR2RGB)
 
+        h, w, _ = color_image.shape
+        if h != self.height or w != self.width:
+            raise OSError(f"Can't capture color image with expected height and width ({self.height} x {self.width}). ({h} x {w}) returned instead.")
+
         # log the number of seconds it took to read the image
         self.logs["delta_timestamp_s"] = time.perf_counter() - start_time
 
@@ -225,7 +231,7 @@ class OpenCVCamera:
         return color_image
 
     def read_loop(self):
-        while True:
+        while self.stop_event is None or not self.stop_event.is_set():
             self.color_image = self.read()
 
     def async_read(self):
@@ -233,6 +239,7 @@ class OpenCVCamera:
             raise RobotDeviceNotConnectedError(f"OpenCVCamera({self.camera_index}) is not connected. Try running `camera.connect()` first.")
 
         if self.thread is None:
+            self.stop_event = threading.Event()
             self.thread = Thread(target=self.read_loop, args=())
             self.thread.daemon = True
             self.thread.start()
@@ -242,27 +249,29 @@ class OpenCVCamera:
             num_tries += 1
             time.sleep(1/self.fps)
             if num_tries > self.fps:
-                if self.thread.ident is None and not self.thread.is_alive():
+                if self.thread.ident is None or not self.thread.is_alive():
                     raise Exception("The thread responsible for `self.async_read()` took too much time to start. There might be an issue. Verify that `self.thread.start()` has been called.")
-
+                
         return self.color_image
 
     def disconnect(self):
         if not self.is_connected:
             raise RobotDeviceNotConnectedError(f"OpenCVCamera({self.camera_index}) is not connected. Try running `camera.connect()` first.")
 
-        self.camera.release()
-        self.camera = None
-
         if self.thread is not None and self.thread.is_alive():
             # wait for the thread to finish
+            self.stop_event.set()
             self.thread.join()
             self.thread = None
+            self.stop_event = None
+
+        self.camera.release()
+        self.camera = None
 
         self.is_connected = False
 
     def __del__(self):
-        if self.is_connected:
+        if getattr(self, "is_connected", False):
             self.disconnect()
 
 
diff --git a/lerobot/common/robot_devices/motors/dynamixel.py b/lerobot/common/robot_devices/motors/dynamixel.py
index 2921d251..79bad051 100644
--- a/lerobot/common/robot_devices/motors/dynamixel.py
+++ b/lerobot/common/robot_devices/motors/dynamixel.py
@@ -101,6 +101,7 @@ MODEL_CONTROL_TABLE = {
 }
 
 
+# TODO(rcadene): find better namming for these functions
 def uint32_to_int32(values: np.ndarray):
     """
     Convert an unsigned 32-bit integer array to a signed 32-bit integer array.
@@ -120,35 +121,18 @@ def int32_to_uint32(values: np.ndarray):
             values[i] = values[i] + 4294967296
     return values
 
-
-def motor_position_to_angle(position: np.ndarray) -> np.ndarray:
-    """
-    Convert from motor position in [-2048, 2048] to radian in [-pi, pi]
-    """
-    return (position / 2048) * 3.14
-
-
-def motor_angle_to_position(angle: np.ndarray) -> np.ndarray:
-    """
-    Convert from radian in [-pi, pi] to motor position in [-2048, 2048]
-    """
-    return ((angle / 3.14) * 2048).astype(np.int64)
-
-
-# def pwm2vel(pwm: np.ndarray) -> np.ndarray:
+# def motor_position_to_angle(position: np.ndarray) -> np.ndarray:
 #     """
-#     :param pwm: numpy array of pwm/s joint velocities
-#     :return: numpy array of rad/s joint velocities
+#     Convert from motor position in [-2048, 2048] to radian in [-pi, pi]
 #     """
-#     return pwm * 3.14 / 2048
+#     return (position / 2048) * 3.14
 
 
-# def vel2pwm(vel: np.ndarray) -> np.ndarray:
+# def motor_angle_to_position(angle: np.ndarray) -> np.ndarray:
 #     """
-#     :param vel: numpy array of rad/s joint velocities
-#     :return: numpy array of pwm/s joint velocities
+#     Convert from radian in [-pi, pi] to motor position in [-2048, 2048]
 #     """
-#     return (vel * 2048 / 3.14).astype(np.int64)
+#     return ((angle / 3.14) * 2048).astype(np.int64)
 
 
 def get_group_sync_key(data_name, motor_names):
@@ -285,15 +269,18 @@ class DynamixelMotorsBus:
 
         return values
 
-    def read(self, data_name, motor_names: list[str] | None = None):
+    def read(self, data_name, motor_names: str | list[str] | None = None):
         if not self.is_connected:
-            raise ValueError(f"DynamixelMotorsBus({self.port}) is not connected. You need to run `motors_bus.connect()`.")
+            raise RobotDeviceNotConnectedError(f"DynamixelMotorsBus({self.port}) is not connected. You need to run `motors_bus.connect()`.")
 
         start_time = time.perf_counter()
 
         if motor_names is None:
             motor_names = self.motor_names
 
+        if isinstance(motor_names, str):
+            motor_names = [motor_names]
+
         motor_ids = []
         models = []
         for name in motor_names:
@@ -352,7 +339,7 @@ class DynamixelMotorsBus:
 
     def write(self, data_name, values: int | float | np.ndarray, motor_names: str | list[str] | None = None):
         if not self.is_connected:
-            raise ValueError(f"DynamixelMotorsBus({self.port}) is not connected. You need to run `motors_bus.connect()`.")
+            raise RobotDeviceNotConnectedError(f"DynamixelMotorsBus({self.port}) is not connected. You need to run `motors_bus.connect()`.")
 
         start_time = time.perf_counter()
 
@@ -444,10 +431,17 @@ class DynamixelMotorsBus:
         if not self.is_connected:
             raise RobotDeviceNotConnectedError(f"DynamixelMotorsBus({self.port}) is not connected. Try running `motors_bus.connect()` first.")
 
-        closePort
+        if self.port_handler is not None:
+            self.port_handler.closePort()
+            self.port_handler = None
+
+        self.packet_handler = None
+        self.group_readers = {}
+        self.group_writers = {}
+        self.is_connected = False
 
     def __del__(self):
-        if self.is_connected:
+        if getattr(self, "is_connected", False):
             self.disconnect()
 
 
diff --git a/lerobot/common/robot_devices/robots/koch.py b/lerobot/common/robot_devices/robots/koch.py
index ba44614a..f133f734 100644
--- a/lerobot/common/robot_devices/robots/koch.py
+++ b/lerobot/common/robot_devices/robots/koch.py
@@ -14,15 +14,21 @@ from lerobot.common.robot_devices.motors.dynamixel import (
     TorqueMode,
 )
 from lerobot.common.robot_devices.motors.utils import MotorsBus
+from lerobot.common.robot_devices.utils import RobotDeviceAlreadyConnectedError, RobotDeviceNotConnectedError
+
+URL_HORIZONTAL_POSITION = {
+    "follower": "https://raw.githubusercontent.com/huggingface/lerobot/main/media/koch/follower_horizontal.png",
+    "leader": "https://raw.githubusercontent.com/huggingface/lerobot/main/media/koch/leader_horizontal.png",
+}
+URL_90_DEGREE_POSITION = {
+    "follower": "https://raw.githubusercontent.com/huggingface/lerobot/main/media/koch/follower_90_degree.png",
+    "leader": "https://raw.githubusercontent.com/huggingface/lerobot/main/media/koch/leader_90_degree.png",
+}
 
 ########################################################################
 # Calibration logic
 ########################################################################
 
-# TARGET_HORIZONTAL_POSITION = motor_position_to_angle(np.array([0, -1024, 1024, 0, -1024, 0]))
-# TARGET_90_DEGREE_POSITION = motor_position_to_angle(np.array([1024, 0, 0, 1024, 0, -1024]))
-# GRIPPER_OPEN = motor_position_to_angle(np.array([-400]))
-
 TARGET_HORIZONTAL_POSITION = np.array([0, -1024, 1024, 0, -1024, 0])
 TARGET_90_DEGREE_POSITION = np.array([1024, 0, 0, 1024, 0, -1024])
 GRIPPER_OPEN = np.array([-400])
@@ -137,11 +143,16 @@ def reset_arm(arm: MotorsBus):
     arm.write("Drive_Mode", DriveMode.NON_INVERTED.value)
 
 
-def run_arm_calibration(arm: MotorsBus, name: str):
+def run_arm_calibration(arm: MotorsBus, name: str, arm_type: str):
+    """ Example of usage:
+        ```python
+        run_arm_calibration(arm, "left", "follower")
+        ```
+    """
     reset_arm(arm)
 
     # TODO(rcadene): document what position 1 mean
-    print(f"Please move the '{name}' arm to the horizontal position (gripper fully closed)")
+    print(f"Please move the '{name} {arm_type}' arm to the horizontal position (gripper fully closed, see {URL_HORIZONTAL_POSITION[arm_type]})")
     input("Press Enter to continue...")
 
     horizontal_homing_offset = compute_homing_offset(
@@ -149,7 +160,7 @@ def run_arm_calibration(arm: MotorsBus, name: str):
     )
 
     # TODO(rcadene): document what position 2 mean
-    print(f"Please move the '{name}' arm to the 90 degree position (gripper fully open)")
+    print(f"Please move the '{name} {arm_type}' arm to the 90 degree position (gripper fully open, see {URL_90_DEGREE_POSITION[arm_type]})")
     input("Press Enter to continue...")
 
     drive_mode = compute_drive_mode(arm, horizontal_homing_offset)
@@ -184,42 +195,15 @@ class KochRobotConfig:
     ```
     """
 
-    # Define all the components of the robot
+    # Define all components of the robot
     leader_arms: dict[str, MotorsBus] = field(
-        default_factory=lambda: {
-            "main": DynamixelMotorsBus(
-                port="/dev/tty.usbmodem575E0031751",
-                motors={
-                    # name: (index, model)
-                    "shoulder_pan": (1, "xl330-m077"),
-                    "shoulder_lift": (2, "xl330-m077"),
-                    "elbow_flex": (3, "xl330-m077"),
-                    "wrist_flex": (4, "xl330-m077"),
-                    "wrist_roll": (5, "xl330-m077"),
-                    "gripper": (6, "xl330-m077"),
-                },
-            ),
-        }
+        default_factory=lambda: {}
     )
     follower_arms: dict[str, MotorsBus] = field(
-        default_factory=lambda: {
-            "main": DynamixelMotorsBus(
-                port="/dev/tty.usbmodem575E0032081",
-                motors={
-                    # name: (index, model)
-                    "shoulder_pan": (1, "xl430-w250"),
-                    "shoulder_lift": (2, "xl430-w250"),
-                    "elbow_flex": (3, "xl330-m288"),
-                    "wrist_flex": (4, "xl330-m288"),
-                    "wrist_roll": (5, "xl330-m288"),
-                    "gripper": (6, "xl330-m288"),
-                },
-            ),
-        }
+        default_factory=lambda: {}
     )
     cameras: dict[str, Camera] = field(default_factory=lambda: {})
 
-
 class KochRobot:
     """Tau Robotics: https://tau-robotics.com
 
@@ -306,6 +290,11 @@ class KochRobot:
         # Orders the robot to move
         robot.send_action(action)
     ```
+
+    Example of disconnecting which is not mandatory since we disconnect when the object is deleted:
+    ```python
+    robot.disconnect()
+    ```
     """
 
     def __init__(
@@ -328,59 +317,68 @@ class KochRobot:
 
     def connect(self):
         if self.is_connected:
-            raise ValueError(f"KochRobot is already connected.")
+            raise RobotDeviceAlreadyConnectedError(f"KochRobot is already connected. Do not run `robot.connect()` twice.")
 
+        if not self.leader_arms and not self.follower_arms and not self.cameras:
+            raise ValueError("KochRobot doesn't have any device to connect. See example of usage in docstring of the class.")
+
+        # Connect the arms
         for name in self.follower_arms:
             self.follower_arms[name].connect()
             self.leader_arms[name].connect()
 
+        # Reset the arms and load or run calibration
         if self.calibration_path.exists():
             # Reset all arms before setting calibration
             for name in self.follower_arms:
                 reset_arm(self.follower_arms[name])
-
             for name in self.leader_arms:
                 reset_arm(self.leader_arms[name])
 
             with open(self.calibration_path, "rb") as f:
                 calibration = pickle.load(f)
         else:
+            # Run calibration process which begins by reseting all arms
             calibration = self.run_calibration()
 
             self.calibration_path.parent.mkdir(parents=True, exist_ok=True)
             with open(self.calibration_path, "wb") as f:
                 pickle.dump(calibration, f)
 
+        # Set calibration
         for name in self.follower_arms:
             self.follower_arms[name].set_calibration(calibration[f"follower_{name}"])
-            self.follower_arms[name].write("Torque_Enable", 1)
-
         for name in self.leader_arms:
             self.leader_arms[name].set_calibration(calibration[f"leader_{name}"])
-            # TODO(rcadene): add comments
-            self.leader_arms[name].write("Goal_Position", GRIPPER_OPEN, "gripper")
-            self.leader_arms[name].write("Torque_Enable", 1, "gripper")
 
+        # Enable torque on all motors of the follower arms
+        for name in self.follower_arms:
+            self.follower_arms[name].write("Torque_Enable", 1)
+
+        # Enable torque on the gripper of the leader arms, and move it to 45 degrees,
+        # so that we can use it as a trigger to close the gripper of the follower arms.
+        for name in self.leader_arms:
+            self.leader_arms[name].write("Torque_Enable", 1, "gripper")
+            self.leader_arms[name].write("Goal_Position", GRIPPER_OPEN, "gripper")
+
+        # Connect the cameras
         for name in self.cameras:
             self.cameras[name].connect()
 
         self.is_connected = True
 
     def run_calibration(self):
-        if not self.is_connected:
-            raise ValueError(f"KochRobot is not connected. You need to run `robot.connect()`.")
-
         calibration = {}
 
         for name in self.follower_arms:
-            homing_offset, drive_mode = run_arm_calibration(self.follower_arms[name], f"{name} follower")
+            homing_offset, drive_mode = run_arm_calibration(self.follower_arms[name], name, "follower")
 
             calibration[f"follower_{name}"] = {}
             for idx, motor_name in enumerate(self.follower_arms[name].motor_names):
                 calibration[f"follower_{name}"][motor_name] = (homing_offset[idx], drive_mode[idx])
 
         for name in self.leader_arms:
-            homing_offset, drive_mode = run_arm_calibration(self.leader_arms[name], f"{name} leader")
+            homing_offset, drive_mode = run_arm_calibration(self.leader_arms[name], name, "leader")
 
             calibration[f"leader_{name}"] = {}
             for idx, motor_name in enumerate(self.leader_arms[name].motor_names):
@@ -392,7 +390,7 @@ class KochRobot:
         self, record_data=False
     ) -> None | tuple[dict[str, torch.Tensor], dict[str, torch.Tensor]]:
         if not self.is_connected:
-            raise ValueError(f"KochRobot is not connected. You need to run `robot.connect()`.")
+            raise RobotDeviceNotConnectedError(f"KochRobot is not connected. You need to run `robot.connect()`.")
 
         # Prepare to assign the positions of the leader to the follower
         leader_pos = {}
@@ -455,7 +453,7 @@ class KochRobot:
 
     def capture_observation(self):
         if not self.is_connected:
-            raise ValueError(f"KochRobot is not connected. You need to run `robot.connect()`.")
+            raise RobotDeviceNotConnectedError(f"KochRobot is not connected. You need to run `robot.connect()`.")
 
         # Read follower position
         follower_pos = {}
@@ -481,9 +479,9 @@ class KochRobot:
             obs_dict[f"observation.images.{name}"] = torch.from_numpy(images[name])
         return obs_dict
 
-    def send_action(self, action):
+    def send_action(self, action: torch.Tensor):
         if not self.is_connected:
-            raise ValueError(f"KochRobot is not connected. You need to run `robot.connect()`.")
+            raise RobotDeviceNotConnectedError(f"KochRobot is not connected. You need to run `robot.connect()`.")
 
         from_idx = 0
         to_idx = 0
@@ -496,3 +494,22 @@ class KochRobot:
 
         for name in self.follower_arms:
             self.follower_arms[name].write("Goal_Position", follower_goal_pos[name].astype(np.int32))
+
+    def disconnect(self):
+        if not self.is_connected:
+            raise RobotDeviceNotConnectedError(f"KochRobot is not connected. You need to run `robot.connect()` before disconnecting.")
+
+        for name in self.follower_arms:
+            self.follower_arms[name].disconnect()
+
+        for name in self.leader_arms:
+            self.leader_arms[name].disconnect()
+
+        for name in self.cameras:
+            self.cameras[name].disconnect()
+        
+        self.is_connected = False
+
+    def __del__(self):
+        if getattr(self, "is_connected", False):
+            self.disconnect()
diff --git a/lerobot/configs/policy/act_koch_real.yaml b/lerobot/configs/policy/act_koch_real.yaml
new file mode 100644
index 00000000..ae29198e
--- /dev/null
+++ b/lerobot/configs/policy/act_koch_real.yaml
@@ -0,0 +1,102 @@
+# @package _global_
+
+# Use `act_koch_real.yaml` to train on real-world datasets collected on Alexander Koch's robots.
+# Compared to `act.yaml`, it contains 2 cameras (i.e. laptop, phone) instead of 1 camera (i.e. top).
+# Also, `training.eval_freq` is set to -1. This config is used to evaluate checkpoints at a certain frequency of training steps. 
+# When it is set to -1, it deactivates evaluation. This is because real-world evaluation is done through our `control_robot.py` script.
+# Look at the documentation in header of `control_robot.py` for more information on how to collect data , train and evaluate a policy.
+#
+# Example of usage for training:
+# ```bash
+# python lerobot/scripts/train.py \
+#   policy=act_koch_real \
+#   env=koch_real
+# ```
+
+seed: 1000
+dataset_repo_id: lerobot/koch_pick_place_lego
+
+override_dataset_stats:
+  observation.images.laptop:
+    # stats from imagenet, since we use a pretrained vision model
+    mean: [[[0.485]], [[0.456]], [[0.406]]]  # (c,1,1)
+    std: [[[0.229]], [[0.224]], [[0.225]]]  # (c,1,1)
+  observation.images.phone:
+    # stats from imagenet, since we use a pretrained vision model
+    mean: [[[0.485]], [[0.456]], [[0.406]]]  # (c,1,1)
+    std: [[[0.229]], [[0.224]], [[0.225]]]  # (c,1,1)
+
+training:
+  offline_steps: 80000
+  online_steps: 0
+  eval_freq: -1
+  save_freq: 10000
+  log_freq: 100
+  save_checkpoint: true
+
+  batch_size: 8
+  lr: 1e-5
+  lr_backbone: 1e-5
+  weight_decay: 1e-4
+  grad_clip_norm: 10
+  online_steps_between_rollouts: 1
+
+  delta_timestamps:
+    action: "[i / ${fps} for i in range(${policy.chunk_size})]"
+
+eval:
+  n_episodes: 50
+  batch_size: 50
+
+# See `configuration_act.py` for more details.
+policy:
+  name: act
+
+  # Input / output structure.
+  n_obs_steps: 1
+  chunk_size: 100
+  n_action_steps: 100
+
+  input_shapes:
+    # TODO(rcadene, alexander-soare): add variables for height and width from the dataset/env?
+    observation.images.laptop: [3, 480, 640]
+    observation.images.phone: [3, 480, 640]
+    observation.state: ["${env.state_dim}"]
+  output_shapes:
+    action: ["${env.action_dim}"]
+
+  # Normalization / Unnormalization
+  input_normalization_modes:
+    observation.images.laptop: mean_std
+    observation.images.phone: mean_std
+    observation.state: mean_std
+  output_normalization_modes:
+    action: mean_std
+
+  # Architecture.
+  # Vision backbone.
+  vision_backbone: resnet18
+  pretrained_backbone_weights: ResNet18_Weights.IMAGENET1K_V1
+  replace_final_stride_with_dilation: false
+  # Transformer layers.
+  pre_norm: false
+  dim_model: 512
+  n_heads: 8
+  dim_feedforward: 3200
+  feedforward_activation: relu
+  n_encoder_layers: 4
+  # Note: Although the original ACT implementation has 7 for `n_decoder_layers`, there is a bug in the code
+  # that means only the first layer is used. Here we match the original implementation by setting this to 1.
+  # See this issue https://github.com/tonyzhaozh/act/issues/25#issue-2258740521.
+  n_decoder_layers: 1
+  # VAE.
+  use_vae: true
+  latent_dim: 32
+  n_vae_encoder_layers: 4
+
+  # Inference.
+  temporal_ensemble_momentum: null
+
+  # Training and loss computation.
+  dropout: 0.1
+  kl_weight: 10.0
diff --git a/lerobot/scripts/control_robot.py b/lerobot/scripts/control_robot.py
index 614989a2..396c7834 100644
--- a/lerobot/scripts/control_robot.py
+++ b/lerobot/scripts/control_robot.py
@@ -1,5 +1,5 @@
 """
-Example of usage:
+Examples of usage:
 
 - Unlimited teleoperation at highest frequency (~200 Hz is expected), to exit with CTRL+C:
 ```bash
@@ -49,15 +49,19 @@ python lerobot/scripts/control_robot.py record_dataset \
     --run-compute-stats 1
 ```
 
-- Train on this dataset (TODO(rcadene)):
+- Train on this dataset with the ACT policy:
 ```bash
-python lerobot/scripts/train.py
+DATA_DIR=data python lerobot/scripts/train.py \
+    policy=act_koch_real \
+    env=koch_real \
+    dataset_repo_id=$USER/koch_pick_place_lego \
+    hydra.run.dir=outputs/train/act_koch_real
 ```
 
 - Run the pretrained policy on the robot:
 ```bash
 python lerobot/scripts/control_robot.py run_policy \
-    -p TODO(rcadene)
+    -p outputs/train/act_koch_real/checkpoints/080000/pretrained_model
 ```
 """
 
@@ -117,29 +121,37 @@ def log_control_info(robot, dt_s, episode_index=None, frame_index=None):
         log_items += [f"ep:{episode_index}"]
     if frame_index is not None:
         log_items += [f"frame:{frame_index}"]
-    
-    # total step time displayed in milliseconds and its frequency
-    log_items += [f"dt:{dt_s * 1000:5.2f}={1/ dt_s:3.1f}hz"]
         
+    def log_dt(shortname, dt_val_s):
+        nonlocal log_items
+        log_items += [f"{shortname}:{dt_val_s * 1000:5.2f}={1/ dt_val_s:3.1f}hz"]
+
+    # total step time displayed in milliseconds and its frequency
+    log_dt("dt", dt_s)
+
     for name in robot.leader_arms:
-        read_dt_s = robot.logs[f'read_leader_{name}_pos_dt_s']
-        log_items += [
-            f"dtRlead{name[0]}:{read_dt_s * 1000:5.2f}={1/ read_dt_s:3.1f}hz",
-        ]
+        key = f'read_leader_{name}_pos_dt_s'
+        if key in robot.logs:
+            log_dt("dtRlead", robot.logs[key])
+
     for name in robot.follower_arms:
-        write_dt_s = robot.logs[f'write_follower_{name}_goal_pos_dt_s']
-        read_dt_s = robot.logs[f'read_follower_{name}_pos_dt_s']
-        log_items += [
-            f"dtRfoll{name[0]}:{write_dt_s * 1000:5.2f}={1/ write_dt_s:3.1f}hz",
-            f"dtWfoll{name[0]}:{read_dt_s * 1000:5.2f}={1/ read_dt_s:3.1f}hz",
-        ]
+        key = f'write_follower_{name}_goal_pos_dt_s'
+        if key in robot.logs:
+            log_dt("dtRfoll", robot.logs[key])
+
+        key = f'read_follower_{name}_pos_dt_s'
+        if key in robot.logs:
+            log_dt("dtWfoll", robot.logs[key])
+
     for name in robot.cameras:
-        read_dt_s = robot.logs[f"read_camera_{name}_dt_s"]
-        async_read_dt_s = robot.logs[f"async_read_camera_{name}_dt_s"]
-        log_items += [
-            f"dtRcam{name[0]}:{read_dt_s * 1000:5.2f}={1/read_dt_s:3.1f}hz",
-            f"dtARcam{name[0]}:{async_read_dt_s * 1000:5.2f}={1/async_read_dt_s:3.1f}hz",
-        ]
+        key = f"read_camera_{name}_dt_s"
+        if key in robot.logs:
+            log_dt("dtRcam", robot.logs[key])
+
+        key = f"async_read_camera_{name}_dt_s"
+        if key in robot.logs:
+            log_dt("dtARcam", robot.logs[key])
+
     logging.info(" ".join(log_items))
 
 ########################################################################################
@@ -147,10 +159,12 @@ def log_control_info(robot, dt_s, episode_index=None, frame_index=None):
 ########################################################################################
 
 
-def teleoperate(robot: Robot, fps: int | None = None):
+def teleoperate(robot: Robot, fps: int | None = None, teleop_time_s: float | None = None):
+    # TODO(rcadene): Add option to record logs
     if not robot.is_connected:
         robot.connect()
 
+    start_time = time.perf_counter()
     while True:
         now = time.perf_counter()
         robot.teleop_step()
@@ -162,6 +176,9 @@ def teleoperate(robot: Robot, fps: int | None = None):
         dt_s = time.perf_counter() - now
         log_control_info(robot, dt_s)
 
+        if teleop_time_s is not None and time.perf_counter() - start_time > teleop_time_s:
+            break
+
 
 def record_dataset(
     robot: Robot,
@@ -174,6 +191,8 @@ def record_dataset(
     video=True,
     run_compute_stats=True,
 ):
+    # TODO(rcadene): Add option to record logs
+
     if not video:
         raise NotImplementedError()
 
@@ -327,8 +346,11 @@ def record_dataset(
 
     # TODO(rcadene): push to hub
 
+    return lerobot_dataset
+
 
 def replay_episode(robot: Robot, episode: int, fps: int | None = None, root="data", repo_id="lerobot/debug"):
+    # TODO(rcadene): Add option to record logs
     local_dir = Path(root) / repo_id
     if not local_dir.exists():
         raise ValueError(local_dir)
@@ -357,7 +379,8 @@ def replay_episode(robot: Robot, episode: int, fps: int | None = None, root="dat
         log_control_info(robot, dt_s)
 
 
-def run_policy(robot: Robot, policy: torch.nn.Module, hydra_cfg: DictConfig):
+def run_policy(robot: Robot, policy: torch.nn.Module, hydra_cfg: DictConfig, run_time_s: float | None = None):
+    # TODO(rcadene): Add option to record eval dataset and logs
     policy.eval()
 
     # Check device is available
@@ -372,6 +395,7 @@ def run_policy(robot: Robot, policy: torch.nn.Module, hydra_cfg: DictConfig):
     if not robot.is_connected:
         robot.connect()
 
+    start_time = time.perf_counter()
     while True:
         now = time.perf_counter()
 
@@ -391,6 +415,9 @@ def run_policy(robot: Robot, policy: torch.nn.Module, hydra_cfg: DictConfig):
         dt_s = time.perf_counter() - now
         log_control_info(robot, dt_s)
 
+        if run_time_s is not None and time.perf_counter() - start_time > run_time_s:
+            break
+
 
 if __name__ == "__main__":
     parser = argparse.ArgumentParser()
diff --git a/media/koch/follower_90_degree.png b/media/koch/follower_90_degree.png
new file mode 100644
index 00000000..66af68a1
Binary files /dev/null and b/media/koch/follower_90_degree.png differ
diff --git a/media/koch/follower_horizontal.png b/media/koch/follower_horizontal.png
new file mode 100644
index 00000000..d2ffb6c5
Binary files /dev/null and b/media/koch/follower_horizontal.png differ
diff --git a/media/koch/leader_90_degree.png b/media/koch/leader_90_degree.png
new file mode 100644
index 00000000..3b802617
Binary files /dev/null and b/media/koch/leader_90_degree.png differ
diff --git a/media/koch/leader_horizontal.png b/media/koch/leader_horizontal.png
new file mode 100644
index 00000000..c55b51a8
Binary files /dev/null and b/media/koch/leader_horizontal.png differ
diff --git a/tests/test_cameras.py b/tests/test_cameras.py
index 522d6188..8048ea05 100644
--- a/tests/test_cameras.py
+++ b/tests/test_cameras.py
@@ -1,5 +1,6 @@
 
 
+from pathlib import Path
 import numpy as np
 import pytest
 
@@ -7,17 +8,28 @@ from lerobot.common.robot_devices.cameras.opencv import OpenCVCamera
 from lerobot.common.robot_devices.utils import RobotDeviceNotConnectedError, RobotDeviceAlreadyConnectedError
 
 
-def test_camera():
-    # Test instantiating with missing camera index raises an error
-    with pytest.raises(ValueError):
-        camera = OpenCVCamera()
+CAMERA_INDEX = 2
+# Maximum absolute difference between two consecutive images recored by a camera.
+# This value differs with respect to the camera.
+MAX_PIXEL_DIFFERENCE = 25
 
-    # Test instantiating with a wrong camera index raises an error
-    with pytest.raises(ValueError):
-        camera = OpenCVCamera(-1)
+def compute_max_pixel_difference(first_image, second_image):
+    return np.abs(first_image.astype(float) - second_image.astype(float)).max()
+
+
+def test_camera():
+    """Test assumes that `camera.read()` returns the same image when called multiple times in a row.
+    So the environment should not change (you shouldnt be in front of the camera) and the camera should not be moving.
+    
+    Warning: The tests worked for a macbookpro camera, but I am getting assertion error (`np.allclose(color_image, async_color_image)`)
+    for my iphone camera and my LG monitor camera.
+    """
+    # TODO(rcadene): measure fps in nightly?
+    # TODO(rcadene): test logs
+    # TODO(rcadene): add compatibility with other camera APIs
 
     # Test instantiating
-    camera = OpenCVCamera(0)
+    camera = OpenCVCamera(CAMERA_INDEX)
 
     # Test reading, async reading, disconnecting before connecting raises an error
     with pytest.raises(RobotDeviceNotConnectedError):
@@ -31,7 +43,7 @@ def test_camera():
     del camera
 
     # Test connecting
-    camera = OpenCVCamera(0)
+    camera = OpenCVCamera(CAMERA_INDEX)
     camera.connect()
     assert camera.is_connected
     assert camera.fps is not None
@@ -50,9 +62,14 @@ def test_camera():
     assert c == 3
     assert w > h
 
-    # Test reading asynchronously from the camera and image is similar
+    # Test read and async_read outputs similar images
+    # ...warming up as the first frames can be black
+    for _ in range(30):
+        camera.read()
+    color_image = camera.read()
     async_color_image = camera.async_read()
-    assert np.allclose(color_image, async_color_image)
+    print("max_pixel_difference between read() and async_read()", compute_max_pixel_difference(color_image, async_color_image))
+    assert np.allclose(color_image, async_color_image, rtol=1e-5, atol=MAX_PIXEL_DIFFERENCE)
 
     # Test disconnecting
     camera.disconnect()
@@ -60,27 +77,29 @@ def test_camera():
     assert camera.thread is None
 
     # Test disconnecting with `__del__`
-    camera = OpenCVCamera(0)
+    camera = OpenCVCamera(CAMERA_INDEX)
     camera.connect()
     del camera
 
     # Test acquiring a bgr image
-    camera = OpenCVCamera(0, color="bgr")
+    camera = OpenCVCamera(CAMERA_INDEX, color="bgr")
     camera.connect()
     assert camera.color == "bgr"
     bgr_color_image = camera.read()
-    assert np.allclose(color_image, bgr_color_image[[2,1,0]])
+    assert np.allclose(color_image, bgr_color_image[:, :, [2,1,0]], rtol=1e-5, atol=MAX_PIXEL_DIFFERENCE)
     del camera
 
-    # Test fps can be set
-    camera = OpenCVCamera(0, fps=60)
-    camera.connect()
-    assert camera.fps == 60
-    # TODO(rcadene): measure fps in nightly?
+    # TODO(rcadene): Add a test for a camera that doesnt support fps=60 and raises an OSError
+    # TODO(rcadene): Add a test for a camera that supports fps=60
+
+    # Test fps=10 raises an OSError
+    camera = OpenCVCamera(CAMERA_INDEX, fps=10)
+    with pytest.raises(OSError):
+        camera.connect()
     del camera
 
     # Test width and height can be set
-    camera = OpenCVCamera(0, fps=30, width=1280, height=720)
+    camera = OpenCVCamera(CAMERA_INDEX, fps=30, width=1280, height=720)
     camera.connect()
     assert camera.fps == 30
     assert camera.width == 1280
@@ -92,7 +111,9 @@ def test_camera():
     assert c == 3
     del camera
 
-
-
-
+    # Test not supported width and height raise an error
+    camera = OpenCVCamera(CAMERA_INDEX, fps=30, width=0, height=0)
+    with pytest.raises(OSError):
+        camera.connect()
+    del camera
 
diff --git a/tests/test_control_robot.py b/tests/test_control_robot.py
index b06bb966..f52c1146 100644
--- a/tests/test_control_robot.py
+++ b/tests/test_control_robot.py
@@ -1,13 +1,47 @@
 
 
+from pathlib import Path
+from lerobot.common.policies.factory import make_policy
+from lerobot.common.robot_devices.robots.factory import make_robot
+from lerobot.common.utils.utils import init_hydra_config
+from lerobot.scripts.control_robot import record_dataset, replay_episode, run_policy, teleoperate
+from tests.utils import DEFAULT_CONFIG_PATH, DEVICE
+
+
 def test_teleoperate():
-    pass
+    robot = make_robot("koch")
+    teleoperate(robot, teleop_time_s=1)
+    teleoperate(robot, fps=30, teleop_time_s=1)
+    teleoperate(robot, fps=60, teleop_time_s=1)
+    del robot
 
-def test_record_dataset():
-    pass
 
-def test_replay_episode():
-    pass
+def test_record_dataset_and_replay_episode_and_run_policy(tmpdir):
+    robot_name = "koch"
+    env_name = "koch_real"
+    policy_name = "act_real"
+
+    #root = Path(tmpdir)
+    root = Path("tmp/data")
+    repo_id = "lerobot/debug"
+
+    robot = make_robot(robot_name)
+    dataset = record_dataset(robot, fps=30, root=root, repo_id=repo_id, warmup_time_s=2, episode_time_s=2, num_episodes=2)
+
+    replay_episode(robot, episode=0, fps=30, root=root, repo_id=repo_id)
+
+    cfg = init_hydra_config(
+        DEFAULT_CONFIG_PATH,
+        overrides=[
+            f"env={env_name}",
+            f"policy={policy_name}",
+            f"device={DEVICE}",
+        ]
+    )
+
+    policy = make_policy(hydra_cfg=cfg, dataset_stats=dataset.stats)
+
+    run_policy(robot, policy, cfg, run_time_s=1)
+
+    del robot
 
-def test_run_policy():
-    pass
\ No newline at end of file
diff --git a/tests/test_motors.py b/tests/test_motors.py
index 95bdc048..2cddd932 100644
--- a/tests/test_motors.py
+++ b/tests/test_motors.py
@@ -3,11 +3,18 @@ import time
 import numpy as np
 import pytest
 from lerobot.common.robot_devices.motors.dynamixel import DynamixelMotorsBus
+from lerobot.common.robot_devices.utils import RobotDeviceAlreadyConnectedError, RobotDeviceNotConnectedError
 
 
 def test_motors_bus():
+    # TODO(rcadene): measure fps in nightly?
+    # TODO(rcadene): test logs
+    # TODO(rcadene): test calibration
+    # TODO(rcadene): add compatibility with other motors bus
+
     # Test instantiating a common motors structure.
     # Here the one from Alexander Koch follower arm.
+    port = "/dev/tty.usbmodem575E0032081"
     motors = {
         # name: (index, model)
         "shoulder_pan": (1, "xl430-w250"),
@@ -17,24 +24,29 @@ def test_motors_bus():
         "wrist_roll": (5, "xl330-m288"),
         "gripper": (6, "xl330-m288"),
     }
-    motors_bus = DynamixelMotorsBus(
-        port="/dev/tty.usbmodem575E0032081",
-        motors=motors,
-    )
+    motors_bus = DynamixelMotorsBus(port, motors)
 
     # Test reading and writting before connecting raises an error
-    with pytest.raises(ValueError):
+    with pytest.raises(RobotDeviceNotConnectedError):
         motors_bus.read("Torque_Enable")
-    with pytest.raises(ValueError):
-        motors_bus.write("Torque_Enable")
+    with pytest.raises(RobotDeviceNotConnectedError):
+        motors_bus.write("Torque_Enable", 1)
+    with pytest.raises(RobotDeviceNotConnectedError):
+        motors_bus.disconnect()
+    
+    # Test deleting the object without connecting first
+    del motors_bus
 
+    # Test connecting
+    motors_bus = DynamixelMotorsBus(port, motors)
     motors_bus.connect()
 
     # Test connecting twice raises an error
-    with pytest.raises(ValueError):
+    with pytest.raises(RobotDeviceAlreadyConnectedError):
         motors_bus.connect()
 
-    # Test reading torque on all motors and its 0 after first connection
+    # Test disabling torque and reading torque on all motors
+    motors_bus.write("Torque_Enable", 0)
     values = motors_bus.read("Torque_Enable")
     assert isinstance(values, np.ndarray)
     assert len(values) == len(motors)
@@ -67,7 +79,5 @@ def test_motors_bus():
     # Give time for the motors to move to the goal position
     time.sleep(1)
     new_values = motors_bus.read("Present_Position")
-    assert new_values == values
+    assert (new_values == values).all()
 
-    # TODO(rcadene): test calibration
-    # TODO(rcadene): test logs?
diff --git a/tests/test_robots.py b/tests/test_robots.py
index e69de29b..a120cb1e 100644
--- a/tests/test_robots.py
+++ b/tests/test_robots.py
@@ -0,0 +1,108 @@
+from pathlib import Path
+import pickle
+import pytest
+import torch
+from lerobot.common.robot_devices.robots.factory import make_robot
+from lerobot.common.robot_devices.robots.koch import KochRobot
+from lerobot.common.robot_devices.utils import RobotDeviceAlreadyConnectedError, RobotDeviceNotConnectedError
+
+
+def test_robot(tmpdir):
+    # TODO(rcadene): measure fps in nightly?
+    # TODO(rcadene): test logs
+    # TODO(rcadene): add compatibility with other robots
+
+    # Save calibration preset
+    calibration = {'follower_main': {'shoulder_pan': (-2048, False), 'shoulder_lift': (2048, True), 'elbow_flex': (-1024, False), 'wrist_flex': (2048, True), 'wrist_roll': (2048, True), 'gripper': (2048, True)}, 'leader_main': {'shoulder_pan': (-2048, False), 'shoulder_lift': (1024, True), 'elbow_flex': (2048, True), 'wrist_flex': (-2048, False), 'wrist_roll': (2048, True), 'gripper': (2048, True)}}
+    tmpdir = Path(tmpdir)
+    calibration_path = tmpdir / "calibration.pkl"
+    calibration_path.parent.mkdir(parents=True, exist_ok=True)
+    with open(calibration_path, "wb") as f:
+        pickle.dump(calibration, f)
+
+    # Test connecting without devices raises an error
+    robot = KochRobot()
+    with pytest.raises(ValueError):
+        robot.connect()
+    del robot
+
+    # Test using robot before connecting raises an error
+    robot = KochRobot()
+    with pytest.raises(RobotDeviceNotConnectedError):
+        robot.teleop_step()
+    with pytest.raises(RobotDeviceNotConnectedError):
+        robot.teleop_step(record_data=True)
+    with pytest.raises(RobotDeviceNotConnectedError):
+        robot.capture_observation()
+    with pytest.raises(RobotDeviceNotConnectedError):
+        robot.send_action(None)
+    with pytest.raises(RobotDeviceNotConnectedError):
+        robot.disconnect()
+
+    # Test deleting the object without connecting first
+    del robot
+
+    # Test connecting
+    robot = make_robot("koch")
+    # TODO(rcadene): proper monkey patch
+    robot.calibration_path = calibration_path
+    robot.connect()  # run the manual calibration precedure
+    assert robot.is_connected
+
+    # Test connecting twice raises an error
+    with pytest.raises(RobotDeviceAlreadyConnectedError):
+        robot.connect()
+
+    # Test disconnecting with `__del__`
+    del robot
+
+    # Test teleop can run
+    robot = make_robot("koch")
+    robot.calibration_path = calibration_path
+    robot.connect()
+    robot.teleop_step()
+
+    # Test data recorded during teleop are well formated
+    observation, action = robot.teleop_step(record_data=True)
+    # State
+    assert "observation.state" in observation
+    assert isinstance(observation["observation.state"], torch.Tensor)
+    assert observation["observation.state"].ndim == 1
+    dim_state = sum(len(robot.follower_arms[name].motors) for name in robot.follower_arms)
+    assert observation["observation.state"].shape[0] == dim_state
+    # Cameras
+    for name in robot.cameras:
+        assert f"observation.images.{name}" in observation
+        assert isinstance(observation[f"observation.images.{name}"], torch.Tensor)
+        assert observation[f"observation.images.{name}"].ndim == 3
+    # Action
+    assert "action" in action
+    assert isinstance(action["action"], torch.Tensor)
+    assert action["action"].ndim == 1
+    dim_action = sum(len(robot.follower_arms[name].motors) for name in robot.follower_arms)
+    assert action["action"].shape[0] == dim_action
+    # TODO(rcadene): test if observation and action data are returned as expected
+
+    # Test capture_observation can run and observation returned are the same (since the arm didnt move)
+    captured_observation = robot.capture_observation()
+    assert set(captured_observation.keys()) == set(observation.keys())
+    for name in captured_observation:
+        if "image" in name:
+            # TODO(rcadene): skipping image for now as it's challenging to assess equality between two consecutive frames
+            continue
+        assert torch.allclose(captured_observation[name], observation[name], atol=1)
+
+    # Test send_action can run
+    robot.send_action(action["action"])
+
+    # Test disconnecting
+    robot.disconnect()
+    assert not robot.is_connected
+    for name in robot.follower_arms:
+        assert not robot.follower_arms[name].is_connected
+    for name in robot.leader_arms:
+        assert not robot.leader_arms[name].is_connected
+    for name in robot.cameras:
+        assert not robot.cameras[name].is_connected
+    del robot
+