NSF-Funded Student Design Projects:
Force Feedback Mouse Used for a Physics Experiment

Designer: Brian Farrell
Client Coordinator: David D. Baldyga, Junior, Mechanical Engineering Student who is legally blind.
Supervising Professor: Robert Erlandson, Ph.D.
Department of Electrical and Computer Engineering
Wayne State University, Detroit, MI 48202

INTRODUCTION
Due to IDEA97, schools are under increasing pressure to include disabled students within the general curriculum so that these students can have an educational experience within the least restrictive environment. Unfortunately, this requirement presents a challenge with respect to the science classroom because teaching science involves hands-on experiments that are often difficult to modify for disabled students.

The Logitech Wingman Force Feedback Mouse is a commercially available device commonly used in video games to provide more realistic user interaction with the computer generated characters and environments.  This project explores the use of the Logitech Wingman Force Feedback Mouse in a computer simulated physics experiment. The intent is to use the force feedback capabilities of the Wingman to provide additional feedback to user.

A blind mechanical engineering student participated in the project as a consultant and collaborator.  It was decided to develop an experiment that explores the relationship between a spring’s length, applied force and spring constant.  The experiment is designed as a gaming system that includes voice feedback, tactile feedback, and sound feedback (auditory homing signal); this design provides a media-rich simulation environment.  The primary objective for this experiment is that in addition to demonstrating a physics principal, the Force Feedback Mouse Experiment is a simple experiment that demonstrates the feasibility of simulating experiments for the visually impaired; thus enabling science teachers to include this segment of the disabled population in physics class experiments.

SUMMARY OF IMPACT
Field-testing of this program was conducted by a junior in mechanical engineering who is legally blind.  The following is an excerpt from his written analysis:
“The computer simulation of the experiment to determine the force constant of a spring by using a force-feedback mouse has advantages for both visually impaired and fully sighted students. This simulation, which is also equipped with voice-assisted instructions, provides an added dimension to a classic physics experiment.  Blind/visually impaired students can benefit from this simulation by being able to perform it with little or no assistance.  The feel of the spring being compressed adds a reality to the simulation that goes far beyond simply crunching numbers in standard computer simulations.  Fully sighted students can benefit from this simulation by also experiencing the feel of the spring being compressed, not just observing number crunching alone.”  Thus, as this testimonial demonstrates, the Force Feedback Mouse Used for a Physics Experiment improves the quality of life for both visually impaired and fully sighted students.
 

TECHNICAL DESCRIPTION

The spring experiment was created using Visual Basic 6.0.  An immersion web type library ActiveX controller was installed to control the force feedback mouse.  The spring experiment uses Microsoft’s Speech Software Development Kit (Speech SDK 4.0) which can be downloaded from Microsoft’s web site. The “Microsoft Voice Text”ActiveX controller was added to the Visual Basic package for text to speech control.  The spring dynamics were simulated using Visual Basic.

The spring experiment application window consists of a pull down menu bar, a “lab helper”, bar graphs for spring length and force applied, and a simulated spring (See Figure 1).  When the application is launched, a voice is heard that walks the user through the menu selections.  The software will read through all of the available choices to assist those users who may be visually impaired.

The first menu selection is located under the File heading. Available options include a Play command that begins the experiment or a Quit command that ends the application (See Figure 3). The second menu selection is labeled Settings. Available options under Settings include the ability to turn the lab helper on or off, turn the voice on or off, and an option to assist the user with finding the spring on the screen. A third menu selection is labeled Go To…. Available options include Overview where the user is instructed as to the significance of Hooke’s law as well as how the experiment is conducted and which parameters of Hooke’s law are measured. Advice is also given to the user as to how to increase the accuracy of the experiment. A Results option is also used to allow the user to view the results of the experiment.

The actual message that the user hears is:
The force exerted by a spring is given by the following equation, which is Hooke's law:  F = -kx
In the above equation, k is the spring constant and x is the displacement from the uncompressed position.
In this virtual experiment you will take up to seven measurements of the force at different spring compression lengths.
From these measurements the spring constant will be calculated.
To obtain the most accurate spring constant you should try to spread out the measurements evenly throughout the possible displacement of the spring.

A final menu item labeled Teacher allows a password protected screen to appear (See Figure 2). This allows staff to adjust the spring constant, length of spring, a length tolerance, a force tolerance, and the ability to change the password. Help is also available for all of the above parameter adjustments.