Instructions/Instructions.txt at master · PeterHa/Instructions · GitHub

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					Using a Pan Tilt Unit (PTU)
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A Pan Tilt Unit as the name suggests allows you to adjust the pan and tilt of the thing connected to the unit (I am using it with a kinect camera on top). I have the Pan Tilt Unit connected via USB to my computer.

I am using the driver found on Washington University's code repository which can be found here:
https://code.google.com/p/wu-robotics/source/browse/

1) Navigate to where you want to put the files.
2) Checkout the code from the repository
	svn checkout http://wu-robotics.googlecode.com/svn/trunk/wu_ptu ptu


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				Creating a urdf model from a .xacro file
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Ros uses urdf models to keep track of the size and shape of a robot, the direction the robot is facing, the position of the robots joints and many more things.

Urdf files are not user editable and are generated from .xacro files using a python script which is included with Ros. .xacro files are just xml and so are user editable.

The script to convert .xacro -> urdf is:
	rosrun xacro xacro.py model.xacro > model.urdf


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			Creating a custom ROS Message type and importing into ROSJava
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To create a custom message type in ROS follow the instructions in the following ROS Tutorial

http://wiki.ros.org/ROS/Tutorials/CreatingMsgAndSrv#Creating_a_msg

To import the custom message type into ROSJava you must first delete the messages compiled and recompile them
To do this cd into the rosjava_messages folder

	roscd rosjava_messages

(Note this command does not work on my setup and so the command that should be used is roscd rosjava_core; cd rosjava_messages)

You can then delete the compiled rosjava messages by using the command:

	rm -rf build/generated-src

Then recompile the source by running the following command:

	../gradlew install

This then recompiles the source and the messages should have been created. To check, check the build/generated-src folder for the folder relating to the name of your message type

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			Importing a ROS Image into the ROSJava BufferedImage format
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To import images from a ROS Image format into the ROSJava BufferedImage format the following code snippet is useful:


import sensor_msgs.Image;

	public void receivedImage(Image image) {
		DataBuffer videoBuffer = new DataBufferByte(image.getData().array(),
				image.getData().array().length);
		latestImage = new BufferedImage(image.getWidth(), image.getHeight(),
				BufferedImage.TYPE_INT_BGR);
		ComponentSampleModel sampleModel = new ComponentSampleModel(
				DataBuffer.TYPE_BYTE, image.getWidth(), image.getHeight(), 3,
				image.getWidth() * 3, new int[] { 2, 1, 0 });
		Raster raster = Raster.createRaster(sampleModel, videoBuffer, null);
		latestImage.setData(raster);
	}

This can be used when using the Kinect camera system to import the rgb image into ROSJava.