ORI ACSL

Applied Computer Simulation Labs

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Virtual Doppler Software Guide


for Software Version 0.9b


Introduction:

Welcome to the ORI Applied Computer Simulation Labs' Virtual Science Lab: Doppler Shift (Virtual Doppler) software. Virtual Doppler provides a virtual science lab learning environment where students are able to experiment with simulated physical variables that make it easier to understand the real-world physics of the acoustic doppler shift phenomenon. The Virtual Doppler software takes advantage of the latest computer gaming technology, including advanced 3-D real-time graphic rendering, and 3-D spatial sound.

The Virtual Doppler science education software is designed to help students with orthopedic impairments better understand how specific physical factors such as relative speed, acceleration, deceleration, and point of view alter the observed acoustical characteristics of a moving sound source through space. The Virtual Doppler software has been designed to be accessible by all persons, including those who are orthopedically challenged. Virtual Doppler may be operated with a standard computer keyboard or any off-the-shelf joystick.

The Virtual Doppler software has been developed as part of a research grant funded by the US Department of Education. The goal of this research is to determine the effectiveness of using simulation software and virtual reality technology to teach the physics of the doppler shift phenomenon, and to provide a virtual laboratory environment for students to apply the scientific method. Virtual Doppler may be especially useful for science teachers who want their students to practice applying the scientific method, and understand how the manipulation of variables relates to changes in the resulting graph from trials that are conducted through the software.

Developer Information:

The Virtual Doppler software is developed by the Oregon Research Institute Applied Computer Simulation Labs. Our address and contact information are shown below.

Oregon Research Institute
Applied Computer Simulation Labs
1715 Franklin Blvd.
Eugene, OR 97403-1983
http://simlabs.ori.org

If you have any questions about how to use the Virtual Doppler software, or if you are having trouble getting the software to function, please refer to contact information below:

Email: http://simlabs.ori.org/contact

Phone: 541-484-2123 x2305


Minimum System Requirements:

  • 800 MHz Pentium or compatible processor.
  • 256 MB RAM.
  • 3-D Sound Card (Creative Audigy series recommended).
  • External stereo speakers or headphones (highly recommended).
  • 3-D Graphic Accelerator Card (NVidia FX series or better recommended)
  • 6 MB of disk space are required to install the software.
  • Windows 2000, XP, or Vista.
  • DirectX 8 (or later).

Additional Recommended Hardware:

  • A headphone distribution amplifier such as the Rolls HA43.
  • High quality headphones.
  • An InterSense InterTrax2 head tracker with 3 Degrees-of-Freedom.


Installing the Virtual Doppler Software:

The Virtual Doppler software can be installed by downloading it directly from our web site.

To install Virtual Doppler do the following:

1) Locate the installer application for Virtual Doppler and double-click it.

Installer Icon


2) Click "Yes" to install the latest version of the software.

Installation Options

3) The installer will show you a default installation path. Click the "Install" button, if the recommended path is okay.

4) You will see this screen when the installation process is complete. Click the "Close" button.


Updating the Virtual Doppler Software:

If an earlier version of Virtual Doppler is already installed on your machine you will see the dialog window below. Click the "Yes" button.

Doppler Setup - Uninstall First

1) Click the "Uninstall" button to uninstall the older version of the Virtual Doppler software.

2) When the uninstall process is complete you will see the following dialog window.

3) The next time you run the Virtual Doppler installer you should see the following dialog window.

Installation Options


Using the Virtual Doppler Software:

To start using Virtual Doppler, double-click its icon.

You will briefly see a "splash" screen that will take you to the http://simlabs.ori.org web site if it is clicked. The splash screen fades after several seconds to reveal the image below.

Virtual Doppler Main Screen


Program Overview:

Virtual Doppler is a 3-D environment that allows a virtual sound object (a yellow sphere) to be activated so it moves across the screen, emitting a pitch, based on the defined parameters of the software. When the yellow sound sphere is activated it will move from left to right along the road in front of you. Its speed and pitch may be adjusted for experimentation purposes, but it will always emit a sound at a constant amplitude with a pitch that models real-world doppler physics.

The Virtual Doppler software can be run entirely with a mouse. You will see a pointer that moves with the mouse position. When the mouse is clicked on the various buttons and sliders within the interface, different features of the software are activated or altered.

The base pitch of the yellow sound sphere is set with the "Pitch" slider at the bottom of the screen. The speed of the sound sphere is set with the "Speed" slider. The distance you are, as an observer, from the path of the sound sphere is set with the "Distance" slider. When the "Run Trial" button is clicked, the yellow sphere will move across the screen from left to right at the speed and base pitch set with the sliders. Data are plotted for each trial and these data may be seen by clicking the "Show Graph" button.

Virtual Doppler with Yellow Sound Sphere Active

The Virtual Doppler simulation with the yellow "sound sphere" active.


The Virtual Doppler Interface:

You will see three buttons on the bottom right portion of the screen. Each button is explained below.

User Interface Buttons

The "Show Graph" button displays a graph that plots the pitch of the animated sound "ball" against time for a number of "trials".

The "Cancel Trial" button cancels the currently running trial so its data are not plotted.

The "Quit" button will quit the simulation.

The distance slider has a range from 0 - 100 meters. This changes the distance you as an observer are from the path of the yellow sound sphere.

Distance Slider

The speed slider has a range from 0 - 100 meters per second. This is the speed the yellow sound sphere will move as it travels from left to right on the roadway in the simulation. Note that the yellow sound sphere accelerates from a speed of 0 meters per second to the set speed, and decelerates from the set speed to 0 meters per second at the end of the trial. This acceleration and deceleration has an effect on the perceived pitch of the sound over time, from the observer's point of view.

Speed Slider

The pitch slider has a range from 220 - 440 cycles per second, or Hertz (Hz). This is the base pitch of the yellow sound sphere. The base pitch will be shifted up or down from the base value, due to the Doppler effect.

Pitch Slider


Graphs:

When a trial is activated, Virtual Doppler plots the pitch of the yellow sound sphere against time to show how various physical parameters such as speed and distance change the perceived pitch of the emitted sound over time, from the observer's point of view.

Virtual Doppler Graph Display

Each trial produces a color-indexed legend that indicates the speed (S), the observer's distance (D), and the pitch of the yellow sound sphere (P) at the time of the trial. Multiple trials may be plotted against each other to see the effect of different speed, distance, and pitch settings.

Graph Plot Legend

The "Save" button saves an image of the graph for further analysis or printout.

The "Clear" button erases all of the trial data in the graph.

Save &  Clear Graph Buttons

When the "Save" button is clicked you will see a dialog window that prompts you for the name the graph image should be given. You may type any legitimate file name and the file will be saved as a standard Windows "BMP" file. The "Cancel" button exits the save dialog and returns you to the graph display window, without saving the graph file.

Save Graph Dialog Window

The graph file is saved to the following path on your hard drive: C:\ORI-ACSL\Doppler\graphs

Once saved, you may view or print any graphs saved to this location. Below, is an example of the image from a saved graph.

Graph Plot Example from Virtual Doppler