Add docs for new HelloNode methods

hello_helpers/README.md

@@ -8,7 +8,7 @@
 
 *fit_plane.py* : Fits planes to 3D data.
 
-*hello_misc.py* : Various functions, including a helpful Python object with which to create ROS nodes. 
+*hello_misc.py* : Various functions, including a helpful Python object with which to create ROS nodes.
 
 *hello_ros_viz.py* : Various helper functions for vizualizations using RViz.
 
@@ -59,6 +59,23 @@ temp.move_to_pose({'joint_lift': 0.4})
 
 #### Attributes
 
+##### `joint_states`
+
+This attribute gives you the entire joint state of the robot as a [JointState](https://docs.ros.org/en/noetic/api/sensor_msgs/html/msg/JointState.html) message. The utility method [`get_joint_state()`](#get_joint_statejoint_name-moving_threshold0001) is an easier alternative to parsing the JointState message.
+
+##### `point_cloud`
+
+This attribute is a [PointCloud2](https://docs.ros.org/en/noetic/api/sensor_msgs/html/msg/PointCloud2.html) message as seen by the head camera. The utility method [`get_point_cloud()`](#get_point_cloud) is an easier alternative to parsing the PointCloud2 message.
+
+##### `tool`
+
+This attribute is the name of the end-effector as a string. You can use this attribute to flag an error for other Stretch users if their robot isn't configured with the correct tool. Most commonly, this attribute will be either `'tool_stretch_dex_wrist'` or `'tool_stretch_gripper'`. To learn about the other end-effectors available for Stretch, or how to create your own and plug it into Stretch's ROS driver, check out the [documentation on tools](https://docs.hello-robot.com/0.2/stretch-tutorials/stretch_body/tutorial_tool_change/).
+
+##### `mode`
+
+This attribute is the mode the robot's driver is in, as a string. See the driver's API to learn more about [driver modes](../stretch_core/README.md#mode-std_msgsstring).
+
+
 ##### `dryrun`
 
 This attribute allows you to control whether the robot actually moves when calling `move_to_pose()`, `home_the_robot()`, `stow_the_robot()`, or other motion methods in this class. When `dryrun` is set to True, these motion methods return immediately. This attribute is helpful when you want to run just the perception/planning part of your node without actually moving the robot. For example, you could replace the following verbose snippet:
@@ -127,13 +144,44 @@ Use this method to get the transform ([geometry_msgs/TransformStamped](https://d
 ```python
 # roslaunch the stretch launch file beforehand
 
-import rospy
 import hello_helpers.hello_misc as hm
 temp = hm.HelloNode.quick_create('temp')
 t = temp.get_tf('base_link', 'link_grasp_center')
 print(t.transform.translation)
 ```
 
+##### `get_joint_state(joint_name, moving_threshold=0.001)`
+
+Use this method to retrieve the joint state for a single joint. It will return a tuple with joint position, velocity, effort, and is_moving as a boolean (checked against the moving_threshold argument). For example:
+
+```python
+# roslaunch the stretch launch file beforehand
+
+import hello_helpers.hello_misc as hm
+temp = hm.HelloNode.quick_create('temp')
+pos, vel, eff, is_moving = temp.get_joint_state('joint_head_pan')
+print(f"The head pan is {'' if is_moving else 'not'} moving")
+```
+
+##### `get_point_cloud()`
+
+Use this method to retrieve the point cloud seen by the head camera as a Numpy array. It will return a tuple with a named array, Nx3 3D point array, timestamp at which the point was captured, and TF frame in which the cloud was captured. For example:
+
+```python
+# roslaunch the stretch launch file beforehand
+
+import hello_helpers.hello_misc as hm
+temp = hm.HelloNode.quick_create('temp')
+cloud, cloud_xyz, capture_time, capture_frame = temp.get_point_cloud()
+print(f"Head camera saw a cloud of size {cloud_xyz.shape} in frame {capture_frame} at {capture_time}")
+# Head camera saw a cloud of size (275925, 3) in frame camera_color_optical_frame at 1695973195045439959
+
+import numpy as np
+i = np.argmax(cloud['z'])
+print(f"If the capture frame is camera_color_optical_frame (i.e. z axis points out from camera), the point furthest from the camera is {np.sqrt(cloud['x'][i]**2 + cloud['y'][i]**2 + cloud['z'][i]**2):.2f}m away and has the color {(cloud['r'][i], cloud['g'][i], cloud['b'][i])}")
+# If the capture frame is camera_color_optical_frame (i.e. z axis points out from camera), the point furthest from the camera is 1.81m away and has the color (118, 121, 103)
+```
+
 ##### `get_robot_floor_pose_xya(floor_frame='odom')`
 
 Returns the current estimated x, y position and angle of the robot on the floor. This is typically called with respect to the odom frame or the map frame. x and y are in meters and the angle is in radians.
@@ -187,4 +235,4 @@ temp.stop_the_robot_service(TriggerRequest())
 
 ## License
 
-For license information, please see the LICENSE files. 
+For license information, please see the LICENSE files.