DUE IN 16 HOURS ENGR 202 LAB

ENGR 202 Evaluation and Presentation of Experimental Data I I

Original: Dr. Scoles

Reaction Time Statistics

Goals:

• Design a LabVIEW user interface to manage the capture of reaction times to a visual

stimulus

• Record these reaction times in a spreadsheet-compatible file

• Analyze and display the statistics of your individual and team results

Materials and Resources

LabVIEW software, LabVIEW reference text

Introduction

This two-week lab involves a basic method of recording reaction times to a visual

stimulus. It provides an extension of your abilities in LabVIEW software and, most importantly,

a means of generating data that can be analyzed and displayed using what you have learned

in lecture.

The goal of the experimental portion of the lab is to generate and collect data from the

user’s response time to a visual stimulus. The stimulus could be the changing color of a front

panel display or the appearance of a simple or complex graphic on the front panel. The

stimulus response should be the clicking of a stop button or, if you prefer, the pressing of a

key on the keyboard. You should do some research into alternate methods of reaction time

experiments.

Once data from all members of the team have been collected, they can be

analyzed and the results displayed and discussed.

Procedure

• Create a LabVIEW user interface (UI) that will

• Capture the name of the user

• Illuminate an LED, set the color of an LED, or show an image after a Start button is

pressed

• The delay between the button press and the UI change should be

randomized with an algorithm such as:

delay = 5 seconds + 5 * RANDOM seconds,

where RANDOM is a number between 0 and 1 generated by the LabVIEW random

number VI. You can adjust the fixed and variable delays as you see fit, but neither

value can be zero.

ENGR 202 Evaluation and Presentation of Experimental Data I I

Original: Dr. Scoles

• Provide a Stop button to be pressed when the screen image (LED or graphic) changes

color or appears

• Provide screen displays for the delay time and reaction time

• Create a LabVIEW block diagram that will generate a spreadsheet-compatible result file

with

• The date and time of the experiment

• The names of the team members

• The course name and lab section

• For each test run

• • The subject name, the start delay, and the reaction time

• With this interface, capture at least 20 tests for each team member. They do not have to

be done consecutively.

• Analyze the results for individual, team and class reaction times in your software of choice

(Excel, LabVIEW, etc.)

This procedure is summarized in Fig. 1.

To write this VI you should review local variables, flat or stacked structures, the Format into

String VI, text file I/O and how to programmatically change the appearance of items:

“You can control programmatically how a VI behaves when it runs, set the appearance of

a control or indicator, or control how the LabVIEW environment behaves. Refer to the

Fundamentals»Programatically Controlling VIs book on the Contents tab in the LabVIEW Help

for more information about these features. 1

Reporting In addition to the normal lab report sections, critical items would include:

• Summary of your research into reaction testing (with references)

• LabVIEW front panel and block diagram (fully documented)

• This should include an explanation, not just graphics

• Data file

• Student names can be replaced by “Student 1, Student 2, ...” if you prefer not to

share your specific results

• Analysis of individual, team and class statistics

• Apply what you have seen in class, homework and Bb Learn

• Does the data follow a normal distribution? Another common distribution?

Turn in a hard copy of your lab and upload an electronic copy to Bb Learn. The hard copy

will be graded according to the lab rubric.

1 Getting Started with LabVIEW, National Instruments, August 2005, p. 5-4.

ENGR 202 Evaluation and Presentation of Experimental Data I I

Original: Dr. Scoles

Figure 1. Procedure summary - read from top to bottom