added ros time usage tutorial

Author: shehzi001

Diff for: fc_ros_tutorials/demo_ros_time/ros_time_examples/CMakeLists.txt

@@ -0,0 +1,27 @@
+cmake_minimum_required(VERSION 2.8.3)
+project(ros_time_examples)
+
+find_package(catkin REQUIRED COMPONENTS
+  geometry_msgs
+  roscpp
+  rospy
+  std_msgs
+  message_generation
+)
+
+catkin_package(
+  CATKIN_DEPENDS 
+    roscpp 
+    rospy 
+)
+
+include_directories(
+  ${catkin_INCLUDE_DIRS}
+)
+
+add_executable(simple_time_example_cpp_node
+  ros/src/simple_time_example_node.cpp)
+
+target_link_libraries(simple_time_example_cpp_node
+   ${catkin_LIBRARIES}
+)

Diff for: fc_ros_tutorials/demo_ros_time/ros_time_examples/package.xml

@@ -0,0 +1,17 @@
+<?xml version="1.0"?>
+<package>
+  <name>ros_time_examples</name>
+  <version>0.1.0</version>
+  <description>The ros_time_examples package</description>
+
+  <maintainer email="[email protected]">Shehzad Ahmed</maintainer>
+
+  <license>GPLv3</license>
+
+  <buildtool_depend>catkin</buildtool_depend>
+  <build_depend>roscpp</build_depend>
+  <build_depend>rospy</build_depend>
+
+  <run_depend>roscpp</run_depend>
+  <run_depend>rospy</run_depend>
+</package>

Diff for: fc_ros_tutorials/demo_ros_time/ros_time_examples/ros/scripts/simple_time_example_python_node

@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+"""
+This script initilizes simple python node.
+"""
+#-*- encoding: utf-8 -*-
+__author__ = 'shehzad ahmed'
+import rospy
+from ros_services_examples.srv import *
+
+def initlize_node():
+    '''
+    Initilize node and spin which simply keeps python 
+    from exiting until this node is stopped
+    '''
+    rospy.init_node('simple_time_example_node', anonymous=False)
+    rospy.loginfo("simple_time_example_node is now running")
+
+    now1 = rospy.Time.now()
+    rospy.loginfo("Current time (now1): %i %i", now1.secs, now1.nsecs)
+
+    now2 = rospy.get_rostime()
+    rospy.loginfo("Current time (now2): %i %i", now2.secs, now2.nsecs)
+
+    rospy.sleep(10.)
+
+    d = rospy.Duration(10, 0)
+    rospy.sleep(d)
+
+    r = rospy.Rate(10) # 10hz
+	while not rospy.is_shutdown():
+		r.sleep()
+
+
+    rospy.spin()
+
+if __name__ == '__main__':
+    initlize_node()

Diff for: fc_ros_tutorials/demo_ros_time/ros_time_examples/ros/src/simple_time_example_node.cpp

@@ -0,0 +1,51 @@
+/**
+ * simple_time_example_node.cpp
+ *
+ * Created on: September 10, 2014
+ * Author: Shehzad Ahmed
+ **/
+#include <ros/ros.h>
+
+void rosTimeExamples()
+{
+    ros::Time now = ros::Time::now();
+
+    ROS_INFO_STREAM("Time Now:" << now);
+
+    ros::Duration duration(5.0);
+
+    ROS_INFO_STREAM("duration:" << duration);
+
+    //ROS duration sleep()
+    ros::Duration(0.5).sleep();
+
+    ros::Rate r(10); // 10 hz
+    while (ros::ok())
+    {
+      r.sleep();
+    }
+}
+
+int main(int argc, char *argv[])
+{
+    /*
+     * Initilization of node
+     */
+    ros::init(argc, argv, "simple_time_example_node");
+
+    /*
+     * Starting node.
+     */
+    ros::NodeHandle nh("~");
+
+    /**
+     * Printing Information message on the console.
+     **/
+    ROS_INFO("simple_time_example_node is now running");
+
+    rosTimeExamples();
+    
+    //ros::spin();
+
+    return 0;
+}