ros2-geek 0.2.0

ROS2 Geek

Create a Node and spin it without blocking.

Usually:

import rclpy
from rclpy.node import Node
from threading import Thread

node = Node("robot", namespace="MK14QWZ024480005")
Thread(target=rclpy.spin, args=(node,), daemon=True).start()

Now:

</code></pre>
<p>Create a publisher which publishes a message every 100ms.</p>
<p>Usually:</p>
<pre lang="python"><code>msg = String()
publisher = node.create_publisher(String, "topic", 10)
timer = node.create_timer(0.1, lambda: publisher.publish(msg))
# update the message
msg.data = "Hello, world!"

Now:

</code></pre>
<p>Wait for a message to be subscribed.</p>
<p>Usually:</p>
<pre lang="python"><code>message = String()
def callback(msg):
    message.data = msg.data
subscriber = node.create_subscription(String, "topic", callback, 10)
while not message.data:
    rclpy.spin_once(node)

Now:

The above comparison is just a simple example. For more complex examples, please read the following tutorial.