Volume 4 No.1, Winter 2000

ISSN# 1523-9926

 

An Interdisciplinary Instrumentation Laboratory

Walter W. Buchanan, PhD, JD, PE
buchanan@coe.neu.edu  
Professor
Electrical Engineering Technology
Northeastern University
Boston, Massachusetts

William E. Cole, PhD
Associate Professor
wcole@coe.neu.edu 
Mechanical Engineering Technology
Northeastern University
Boston, Massachusetts


ABSTRACT

Northeastern University introduced an Interdisciplinary Instrumentation Laboratory into its Freshman Engineering Technology Curriculum in the fall of 1999. This laboratory was modeled after the freshman laboratory experience developed at Drexel University and in the initial quarter the first eight experiments from the Drexel Laboratory were used. Internet delivery was used to guide the students through the experiments. These experiments introduced basic measurement skills, including both electrical and mechanical measurements. The purpose of the laboratory was to:

        Provide students with a hands-on experience;

        Develop self learning skills;

        Develop critical thinking skills; and,

        Provide a basis to help the students decide between the Computer Technology, Electrical Engineering Technology, and Mechanical Engineering Technology programs offered at Northeastern University.

The second part of this laboratory was administered to the same students in the spring of 2000. Described in this paper are the experiments, the delivery at Northeastern, and an assessment of the laboratory effectiveness.

 

INTRODUCTION

In January of 1999, six faculty members from the College of Engineering visited Drexel University to review their pioneering freshman program, including the instrumentation laboratory. The Drexel curriculum and the laboratory are described in Reference 1. In the laboratory, each workstation was equipped with a digital multimeter, power supply, function generator, oscilloscope, and computer. All instruments were computer connected using the HPIB (Hewlett Packard Interface). The experiments were all available on the Internet at the Drexel site2 and available in a published text3. Students enter the laboratory (with no preparation), perform the experiments as outlined on the Internet site, and complete a quiz at the end of the laboratory. They are then done with the experiment with no homework or further data analysis is required.

Representatives from the School of Engineering Technology were impressed with this laboratory experience. We saw it as an opportunity for the students to obtain hands-on experience before they had to decide on their major (Northeastern University offers Bachelor degree programs in Computer, Electrical, and Mechanical Engineering Technology with the students selecting their major in the sophomore year). We also saw this laboratory as an opportunity to implement some of the ideas in our Academic Common Experience (ACE) program. The ACE program at Northeastern University is a novel approach to teach students in all majors basic core material that is common to all fields. Specific ACE values that the students will practice in this laboratory include developing self-learning and critical thinking skills. Introducing them to new technologies through the readings on the Internet and performing experiments in the laboratory, not through the traditional lecture, will develop self-learning skills. Critical thinking skills will be developed by requiring the students to think about what they did in the laboratory, consider the implications, and extend the results to other situations.

With these thoughts in mind, we decided to implement the instrument laboratory in our freshman Engineering Technology Program. Our plan was to complete eight experiments from the Drexel site in the fall quarter and an additional eight experiments in the spring quarter (Northeastern University is on the quarter system with each quarter being ten weeks long). Initial implementation occurred in the fall of 1999 using an existing electrical engineering laboratory. The facility includes nine workstations equipped with a Tektronix oscilloscope, a Keithley multimeter, a Power Systems power supply, and a Tektronix function generator. This facility is shown in Figure 1. In the summer of 1999, computers were installed at each workstation along with connections to the Internet for each computer.

 

Figure 1. The Northeastern University Instrument Laboratory

 

INITIAL IMPLEMENTATION OF THE INSTRUMENT LABORATORY

Initial implementation of this instrument laboratory was in the fall of 1999. For this initial course the eight experiments from the Drexel Site were used. These eight experiments were:

  1. DC Voltage and Current: Uses a digital multimeter to measure the potential difference, voltage, and current in batteries, circuits, thermocouples and a solar cell.
  2. Resistance: Uses a multimeter and Ohm's Law to measure resistance. Also uses DC powers supplies and include plotting and interpreting characteristic current-voltage curves.
  3. Parallel and Series Circuits: Investigates current flow in series and parallel circuits and Kirchoff's Law. Also involves calculating equivalent resistance and building series, parallel, and combination circuits. Demonstrates use of a Wheatstone Bridge.
  4. Network Theorems and Devices: This experiment presents Thevenin's Theorem and the Maximum Power Transfer Theorem. Students construct circuits based on these theorems and then conduct experiments to verify these theorems.
  5. Force, Length, and Mass I: Experiment presents measurement terms including uncertainty, error, hysteresis, accuracy, mean, and standard deviation. Students measure length and determine the accuracy of specified instruments. Students also analyze data and construct a histogram.
  6. Force, Length, and Mass II: Students use a strain gage to measure voltage and weight changes. Students also calibrate and use different scales to measure mass, and analyze data on a spreadsheet.
  7. Time Varying Signals I: Introduces the terms: magnitude, frequency, period, amplitude, and root mean square voltage. Students use a function generator and an oscilloscope to measure AC voltage, period, RMS values and frequency of sine, square, and triangular waves.
  8. Time Varying Signals II: With an understanding of time varying signals I, students measure the relationship between amplitude and effective value for AC voltages. Students also verify Kirchoff's Law for AC circuits.

The first four experiments were accessed directly from the Drexel Internet site. For the second four experiments, changes were required in the write-up to reflect the different equipment and setup. Hence, the original write-ups were modified and loaded individually on the computer at each workstation. Modifications to the original write-ups were minor reflecting equipment changes only, not a change in objectives or tasks in the experiment.

The course was required for all our incoming (first quarter) freshman students. We had 92 students registered in the course and six sessions of the laboratory were offered. The course was offered on a pass fail basis with the grade based solely on the exit quiz taken by the students at the end of the laboratory. The students earned one credit for completing this course. No preparation was required by the students and no post laboratory work was required. Figure 2 shows several students doing the sixth experiment in the laboratory.

Figure 2. Students performing the sixth experiment in the laboratory

One addition we did make to the Drexel program, however, was to require the students to maintain a laboratory notebook. This was implemented to start them into the practice of keeping a laboratory notebook to record their work in the laboratory.

For proctoring in the laboratory, a graduate student Teaching Assistant was responsible for the students in the laboratory and conducting each laboratory period. He was assisted, in each laboratory, by an upper class Engineering Technology student (a junior year student). Three different students were used to proctor these laboratories, one was an electrical and two were mechanical engineering technology majors. Additionally, SET faculty were actively involved with the laboratories. Two different faculty members were responsible for different sections of the laboratory, one a Mechanical Engineering Technology faculty member and the second an Electrical Engineering Technology faculty member. They prepared the experiments and supervised the student proctors. A faculty member was in the laboratory for at least one hour during each of the laboratory sessions. Additionally, other faculty members stopped by the laboratory at least once a week to see how it was going.

 

LABORATORY EVALUATION

Overall the laboratory went well. Students worked diligently in the laboratory and completed their experiments within the allotted time period. However, it was necessary to change the experiments to provide a better balance between the computer, electrical, and mechanical engineering technology disciplines offered at Northeastern. Makeup laboratories, originally a concern of the authors, were not a problem. Few students missed laboratories and one extra workstation was available in the laboratory for each of the six laboratory periods each week for students to make-up a missed laboratory.

A student evaluation of the laboratory course was conducted at the conclusion of the course. Overall, the students gave the course a "B". They found the hands-on features of the course interesting and fun. However, there was some disagreement in the comments. About ten percent of the students implied that this laboratory was totally duplicative of things they had done in high school. Another twenty percent indicated that the material was totally foreign to them and too complex. Thus it appears that the overall complexity of these laboratories was appropriate for the engineering technology students. This is an interesting observation since the laboratories were developed for engineering students. Overall, the complexity of the laboratories was rated a "C", neither too complex, nor too simple. However, the standard deviation of the students was wide, meaning there was disagreement among the students.

The students rated the laboratory as organized and well run. This really rates the structure of the Drexel program. The students also indicted that the experimental write-ups were good. However, they indicated that the directions and explanations were frequently unclear. Hence, for use in engineering technology programs, it would be wise to expand the experimental write-ups available from Drexel.

Many students also suggested that lectures be provided before each laboratory to introduce the material and the procedures of the laboratory. The concern with lectures, however, is that we want to show the students that they can learn on their own and that the laboratory is a learning place - the lecture hall is not the only place to learn. At Rensselaer Polytechnic Institute they were able to implement lecture periods without removing these aspects of the laboratory. They used a one hour lecture each week where the first half of the class was devoted to reviewing the principles that the students learned in the previous laboratory and the second half presented material for the next laboratory. "New material was intentionally kept at a minimum so that some aspects are left for discovery in the laboratory."4

Using upper class students as laboratory proctors was an experiment for Northeastern University. In the past, only graduate students have been used as laboratory proctors. The students liked the use of upper class undergraduate students as laboratory proctors. They rated the student proctors a "B+" and recommended that the practice be continued.

 

PART 2 OF THE LABORATORY EXPERIENCE

The second part of this course was offered in the spring of 2000. A number of changes were made to the laboratory between the fall course and the spring course. First, all the instrumentation was replaced in the laboratory. Each workstation was equipped with an Agilent Technologies Oscilloscope, Power Supply, Multimeter, and Signal Generator. Additionally, all these instruments were connected to the computer through a HPIB. A general-purpose data acquisition board was also installed in each computer. HP-VEE was installed on all the computers to communicate with the instruments.

Based on the student's comments, major changes were made in the structure of the laboratory course. Totally new laboratories were written for this course. These new laboratories were structured around two specific themes, allowing greater depth of the experiments and analogies between mechanical, electrical, and computer technologies. Experimental write-ups were also expanded to include a greater background explanation and clarify the procedures. A weekly lecture was also incorporated into the course and the studentsí grades were based solely on the their laboratory notebooks. These experiments can be found at the web site http://www.coe.neu.edu/Depts/SET/get1122

The first theme was structured around the phenomena of oscillatory systems and resonance. An electrically resonant system (LRC circuit) was constructed and tested, a physical system was tested, and the phenomenon was modeled in Electronics Workbench. For the second theme, computer interface, and automatic control were explored. In a series of experiments the students interfaced a thermistor to the computer and calibrated it to measure temperature (using HP-VEE), and then outputted a signal to control the power going to a power resistor fastened to the thermistor. Both simple on/off and proportional control were implemented.

 

FUTURE PLANS

We plan on continuing this instrument laboratory at Northeastern University. Next implementation will be in the fall of 2000. Again, we plan on reorganizing the first part of the laboratory experience around two themes. This format seems to work better with the students than sequential experiments. Experimental write-ups will also be expanded to include more background explanation and clarify the procedures. Another change will be to provide a more equal balance between electrical, computer and mechanical experiments.

 

CONCLUSIONS

We are very pleased with the implementation of the instrument laboratory into the engineering technology curriculum at Northeastern University. Specifically we find that it:

        Provides the students with a hands-on experience;

        Develops self learning skills;

        Develops critical thinking skills; and,

        Provides a basis to help them decide between the Electrical Engineering Technology, Mechanical Engineering Technology, and Computer Technology programs offered at Northeastern University.

The students agree with this assessment.

 

BIBLIOGRAPHY

1.

Quinn, Robert G., "The E4 Introductory Engineering Test, Design, and Simulation Laboratory," Journal of Engineering Education, October 1993, p. 223.

2.

http:/iae.coe.drexel.edu

3.

Quinn, Robert and Carr, Robin, "Introduction to the Art of Engineering," Wiley Custom Services, John Wiley and Sons, Inc., ISBN 0-471-32417-5.

4.

Carlson, Bruce, et. al., "A Motivational First-year Electronics Laboratory Course," Journal of Engineering Technology, October 1997, pp. 357-362.

 

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