- Email: [email protected]
Asynchronous hands-on experiments for Mechatronics education
Mechatronics 12 (2002) 251±260
Asynchronous hands-on experiments for Mechatronics education Burford J. Furman a
a,*
, Gregory P. Hayward
b
Department of Mechanical and Aerospace Engineering, San Jos e State University, San Jos e, CA 95192-0087, USA b Caspian Networks, San Jos e, CA 95134, USA
Abstract There has been great interest and eort at many engineering educational institutions to introduce on-line, or ``asynchronous'' courses. However, at the present time, the vast majority of on-line or distance education courses lack any hands-on activities that require the manipulation of physical artifacts or physical experimentation. This paper describes a series of hands-on Mechatronics experiments associated with an introductory Mechatronics course that could be done ``anytime, anywhere'' (asynchronously). The experiments are based on a relatively inexpensive ``kit'' of components and a single-board microcontroller. Ó 2002 Published by Elsevier Science Ltd.
1. Introduction The last two decades in the 20th century have been a period of rapid change in engineering education. Three notable developments have been the ``re-engineering'' of engineering education to include a better balance between analytical engineering science and concrete, hands-on engineering practice [1], the explosion of distance education opportunities particularly through the Internet [2], and the emergence of Mechatronics curricula in US institutions [3]. There has been great interest from many engineering colleges around the world to implement on-line courses over the Internet for courses in degree programs and for continuing education [4,5]. In fact, a study on Distance Education for all types of education found that by fall 1998, 90% of all institutions with 10,000 students or
*
Corresponding author. Tel.: +1-408-924-3817; fax: +1-408-924-3995. E-mail address: [email protected] (B.J. Furman).
0957-4158/02/$ - see front matter Ó 2002 Published by Elsevier Science Ltd. PII: S 0 9 5 7 - 4 1 5 8 ( 0 1 ) 0 0 0 6 5 - 4
252
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
more and 85% of institutions with enrollments between 3000 and 10,000 were expected to oer at least some kind of Distance Education courses [6]. These ``Distance Ed'' or ``asynchronous'' courses as they are sometimes called are attractive for a variety of reasons: · Students can take the course at their convenience rather than having to go to class at a predetermined time and location. · Students can proceed through the course material at their own pace. · A wider pool of students can be reached than is possible by traditional means. · Course materials can be more easily adapted to facilitate access by the disabled. · The Internet oers unique capabilities for multimedia instruction, collaboration, and interactivity [5]. However, at the present time, the vast majority of on-line or distance education courses lack any hands-on activities that require the manipulation of physical artifacts or physical experimentation (see for example the courses in various engineering disciplines at the World Lecture Hall web site [7]). This is a logical result, because courses that are mostly conceptual are the easiest to adapt from a traditional classroom method of delivery to an asynchronous format. But, hands-on experience is a vital ingredient of any high-quality engineering program. Some reasons why hands-on experience is so important are: · Students need to be exposed to the practice of engineering in addition to engineering science. · Engineering graduates must be able to ``design and conduct experiments, as well as analyze and interpret data'' [8]. · Students need to become familiar with the instruments and equipment common in engineering practice for subsequent work in industry or advanced study. · A large percentage of engineering students are visual, sensing, and active learners [9], and it is necessary for them to see, touch and feel things before they can fully process engineering concepts. There has also been signi®cant activity in the last decade to revise engineering curricula to include more design and concrete engineering practice rather than just engineering science [1]. This has particularly been the case in the development of freshmen engineering courses, where emphasis has been given on engaging students in engineering through problem-solving and hands-on design projects from the beginning of their program rather than at their senior year. On the other hand, most on-ground courses that provide signi®cant hands-on experience have an associated physical laboratory. This is particularly true of courses in Mechatronics [10±12]. Physical laboratories, however, pose some dicult challenges in many engineering curricula: · They require relatively large amounts of limited, physical space in a building. · Laboratory equipment is expensive to purchase, maintain, and upgrade. · They can be expensive to run, because of the relatively high number of contact hours associated with laboratory sections. · Many laboratory spaces, despite the eort and cost it takes to put them together, end up being grossly underutilized. · Existing facilities may not allow full access for handicapped individuals [13].
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
253
Because courses that provide signi®cant hands-on experience usually require a physical laboratory, there is a fundamental mismatch with oering them as distance education courses. This is a major barrier toward oering, for example, a complete on-line degree program of equivalent quality to a traditional on-ground program. Thus, in light of the desirability of hands-on experiences (especially for Mechatronics) and the challenges facing their incorporation in the curriculum, the authors see an opportunity to improve the current state of aairs by developing hands-on experiences for an introductory course in Mechatronics that do not require a physical laboratory, but can be carried out by students ``anytime, anywhere'' (asynchronously).
2. Background and approach The authors are developing a series of asynchronous Mechatronics experiments to be piloted in ME 106, Fundamentals of Mechatronics, at San Jose State University. ME 106 is a required course for all mechanical engineering students that seeks to expose them to analog electronics, digital electronics, sensors and transducers, actuators, and microprocessors. Lectures are intended to provide the student with foundational concepts in mechatronics and practical familiarity with common elements making up mechatronic systems. Laboratory experiments are designed to give the student hands-on experience with components and measurement equipment used in the design of mechatronic products [14]. The three prerequisites for the course are: Computer Applications (i.e., computer programming), Introduction to Circuit Analysis, and Dierential Equations. Most students take ME 106 in their junior year. Presently, there are 12 experiments in ME 106, and students perform one per week, in a 3-h laboratory period. Details of these experiments are available on the Internet [14]. The experiments are performed in a well-equipped laboratory consisting of ten work stations each with its own set of test and measurement equipment and networked PC [11]. The overall educational goals for the asynchronous experiments are essentially the same as for those conducted in the physical laboratory. Further, some new approaches will be taken to decouple the learning environment from a dedicated laboratory on campus and to more tightly integrate the learning experience. For example, a ``kit'' of relatively inexpensive, readily available components has been de®ned which the student will use to perform the laboratory experiments at a location and time of his or her choosing. The kits can be purchased from the Department or assembled by the student from local electronics stores such as Radio Shack. The kit components are listed in Appendix A. The student will build or purchase (from the Department) a single-board microcontroller, designed by the authors, called the ``Mechatronics for Autonomous Devices (or MAD) board. The MAD Board is based on the Motorola 68HC11
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B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
microcontroller, and borrows design and operational features from the MIT Handy Board [15] and Marvin Green's BOTBoard 2 [16]. This approach has been taken for several reasons: · The MAD Board is relatively inexpensive, about $50 for its components. · It can be programmed with Interactive C (IC) or by using other freeware or commercial C compilers. · It can control DC motors and servos directly from the board, and it has an 8-bit ADC converter as part of the 68HC11 chip. · It is relatively simple to build, debug, and maintain. The parts for the MAD Board are listed in Appendix B. It will be assumed that the student will have or can borrow a personal computer with a sound card. Hagler and Mehrl, have pioneered the use of a PC sound card as an audio waveform generator and oscilloscope for measurements on simple signal processing circuits [17]. A similar approach will be used in one of the asynchronous experiments to enable a student to explore the behavior of RC ®lters for ®ltering noisy signals from sensors. The student will also need a multimeter and soldering iron. Approximate costs for these items and an example supplier are listed in Appendix C. 3. Asynchronous experiments The asynchronous experiments are designed to be integrative, and they culminate with the student building an autonomous vehicle that must negotiate a prede®ned ``playing ®eld'' and that will score points by manipulating ping±pong balls. There are 11 ``experiments''. Besides the ®rst two, each involve the use of the MAD Board and introduce the student to fundamental concepts such as Ohm's law, digital input/output, ADC conversion, use of transistors to control power, etc. The sequence is: 1. MAD Board Build (week 1). 2. MAD Board Build (week 2). 3. MAD Board Familiarization. 4. RC Filters and Op-amps. 5. On/O Motor Control. 6. PWM Motor Speed Control. 7. Pulse Accumulation and Speed Measurement. 8. Autonomous Vehicle Power Train Bring-up. 9. Autonomous Vehicle Sensor Bring-up. 10. Autonomous Vehicle Integration. 11. Autonomous Vehicle Performance Demo. The student will be strongly encouraged to build his or her own MAD Board during the ®rst two weeks. Not only will the student learn to solder, but also he or she will gain a deeper understanding of how the board is laid out and how it functions. We anticipate that we will need to oer demonstrations and/or create tutorial resources to help students learn to solder and use a multimeter.
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
255
In the third experiment, the student will verify voltage division and Ohm's law, explore the resistance behavior of photoresistors, and get familiar with the ADC system of the 68HC11 by using it to determine the voltage in a resistive network. The learning goal for this experiment is to become familiar with a multimeter, solderless breadboard, resistors, photoresistors, and how to write a program to control the MAD Board. In the fourth experiment, the student will explore the characteristics of RC ®lters using a PC sound card following the approach of Hagler and Mehrl [17]. Operational ampli®ers and the concept of signal ampli®cation will be explored. The student will build an ampli®er to maximize the input range of the ADC on the MAD Board and write a program to capture an AC signal. The ®fth experiment will have the student become familiar with the digital input/ output (IO) capability of the MAD Board and explore the use of transistors to control power. The student will use the ADC port on the MAD Board with an analog sensor and the digital IO port with transistors to turn a motor on or o and control the direction of rotation depending on the output from the sensor. The sixth experiment will have the student explore Pulse Width Modulation (PWM) and how it can be used to control the speed of a motor. The student will write a program for the MAD Board to control the speed of a DC motor depending on the voltage set by a potentiometer. In the seventh experiment, the student will explore how to use the MAD board to count pulses and determine the speed of a rotating wheel. The seventh, eighth, and ninth experiments will focus on the major aspects of bringing up the student's autonomous device. The ®nal experiment will be a demonstration of the vehicle's performance on a prede®ned playing ®eld. Students will be required to submit their vehicle to the instructor three days prior to the performance demonstration. 4. Implementation plan The MAD Board and asynchronous experiments are under development. By the end of August 2000, the layout and fabrication of a prototype MAD Board and details for experiments 3 and 4 are expected to be completed. The remaining experiments will be developed during the fall of 2000. The authors hope to begin piloting the experiments during the fall of 2000. 5. Summary and conclusions A series of introductory, hands-on Mechatronics experiments are under development that do not require a physical laboratory in which to perform them. The experiments will introduce the student to fundamental concepts in Mechatronics, yet do so at the pace and convenience of the student. The experiments are designed to be integrative so that knowledge gained in earlier experiments can be applied in
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Table 1 Parts list of components needed for asynchronous experiments (prices in FY2000 dollars) Description
Quantity Value
Switching diodes 100 X resistor 5 mm 500 mA fuse 5 mm fuse holder Phone jack
4 1 1 1 2
1N4148 100 X 500 mA Stereo
Double binding posts, dual 2 banana ABS Speedy Box 1 6 3:5 1:9 in. Stereo 1/8 in. phone cables 2 Solderless breadboard 1/2 W shaft pot Hookup wire, red Hookup wire, black Hookup wire, green LED, green LED, red CdS Photoresistor DPDT mini toggle switch
1 1 3 3 3 2 2 1 1
SPST mini toggle switch 1 k 1/4 W resistor 10k 1/4 W resistor 0.22 lF capacitor 2N3904 NPN transistor TIP120 Power Darlington IRF510 Power MOSFET Opto Interrupter module L293D Push-Pull Driver 5 V DPDT relay
1 6 2 1 2 4 2 2 1 1
DC motor
2
10 K ft. 22 AWG ft. 22 AWG ft. 22 AWG T1, 3 mm T1, 3 mm 10±100k DPDT on±o±on SPST on±o 1K 10 K 0.22 lF 2N3904 TIP120 IRF510 L293D 5 V, 120 VAC 1A 1.5±3 V DC
Price ea.
Price ext. Catalog no.
Supplier
$0.04 $0.05 $0.02 $0.75 $1.01
$0.16 $0.05 $0.02 $0.75 $2.01
36038 R100 102040 150463 274-249
$2.49
$4.98
125196
Jameco JDR Jameco Jameco Radio Shack Jameco
$2.95
$2.95
18892
Jameco
$3.99
$7.98
42-2387
$11.95 $0.99 $0.03 $0.03 $0.03 $0.11 $0.11 $0.55 $1.09
$11.95 $0.99 $0.09 $0.09 $0.09 $0.22 $0.22 $0.55 $1.09
20757 29081 36863 36804 36839 LED100 LED101 136047 26358
Radio Shack Jameco Jameco Jameco Jameco Jameco JDR JDR Jameco Jameco
$1.09 $0.05 $0.05 $0.23 $0.06 $0.59 $0.46 $0.85 $2.00 $2.49
$1.09 $0.30 $0.10 $0.23 $0.12 $2.36 $0.92 $1.70 $2.00 $2.49
76523 R1k R10k M.22 38359 32993 273-0233 H21A1QT-ND 511-L293D 139977
Jameco JDR JDR JDR Jameco Jameco Allied Digi-Key Mouser Jameco
$1.29
$2.58
273-223
Radio Shack
Total $48.07 Supplier contact information: Allied Electronics, Inc., http://www.alliedelec.com, 1-800-433-5700. B.G. Micro, 55 N. 5th St., Suite 125, Garland, TX 75040, 1-800-276-2206. Digikey, http://www.digikey.com, 1-800-344-4539. Jameco Electronics, http://www.jameco.com, 1-800-831-4242. JDR Microdevices, http://www.jdr.com, 1-800-538-5000. Mouser Electronics, http://www.mouser.com, 1-800-346-6873. Radio±Shack, http://www.radioshack.com.
Table 2 Parts list for MAD board (prices in FY2000 dollars) Description
Quantity Value
PC board
1 V
Price ea.
Price ext.
$8.50
$8.50
Catalog no.
Supplier
2 7 2 1 4 4
47 lF 0.1 lF 22 pF 100 lF 22 lF 10 lF
C1, C2 C3±C9 C10, C11 C12 C13, C14, C15, C16 C17, C18
$0.06 $0.15 $0.09 $0.06 $0.07 $0.04
$0.12 $1.05 $0.18 $0.06 $0.28 $0.16
31114 25523 81533 93761 158326 29891
JAMECO JAMECO JAMECO JAMECO JAMECO JAMECO
Resistors 5% precision 5% precision 5% precision Resistor Pack SIP Resistor Pack SIP Resistor Pack SIP
1 1 1 2 1 2
10 K 10 meg 470 X 10 K, 6 pins 5 RES. 1 K, 8 pin 4 RES. 47 K 10 pin 9 RES.
R1 R2 R3 R4, R5 R6 R7, R8
$0.27 $0.27 $0.27 $0.25 $0.32 $0.25
$0.27 $0.27 $0.27 $0.50 $0.32 $0.50
10MQBK-ND 10KQBK-ND 470QBK-ND 773061103-ND 773083102-ND 98087
Digikey Digikey Digikey Digikey Digikey JAMECO
IC's 6811 microprocessor Octal D-type ¯ip/¯op tri-state 32 K static CMOS RAM Triple 3-input NAND 3±8 decoder/multiplexer RS232 converter Quad 2-input Schmitt NAND Transparent Octal D-type Latch Motor driver Octal D-type ¯ip/¯op edge-trig 5 V, 1 A regulator
1 1 1 1 1 1 1 1 1 1 1
MC68HC11A1FN 74HC573 62256-32K 100 74HC10 74HC138 MAX232 74HC132 74HC373 L293 74HC374 7805T
U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11
$10.00 $0.79 $2.25 $0.19 $0.35 $3.98 $0.35 $0.45 $5.00 $0.45 $0.29
$10.00 $0.79 $2.25 $0.19 $0.35 $3.98 $0.35 $0.45 $5.00 $0.45 $0.29
68HC11 46076 62256LP-10 45233 45330 MAX232EWE-ND 45321 45831 296-2128-5ND 45858 51262
B.G. MICRO JAMECO JAMECO JAMECO JAMECO Digikey JAMECO JAMECO Digikey JAMECO JAMECO
V V V
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
Capacitors Mini Radial 'lytic, 50 Monolithic Ceramic Monolithic Ceramic Mini Radial 'lytic, 25 Mini Radial 'lytic, 35 Mini Radial 'lytic, 50
Reference
257
258
Table 2 (Continued) Quantity Value
Sockets 52 PIN PLCC Socket 16 pin DIP 20 pin DIP 28 pin DIP 14 pin DIP
1 4 1 1 1
52 16 20 28 14
Miscellaneous Serial Connector 3 pin Headers 4 pin Headers 8 MHz Crystal Red LED Green LED Speaker Push Button Switch Polyswitch Fuse Inductor
1 4 4 1 1 1 1 2 1 2
DB-9 3 pin Headers 4 pin Headers 8 MHz Crystal Red LED Green LED Speaker Switch momentary Fuse 1uH
Reference
PIN PLCC. pin DIP pin DIP pin DIP pin DIP DB9F Pwr., Bat., S1-S4, J1, J2 AD0-AD3, SCI X1 LED1 LED2 PZ S1, S2 F1 L1
Price ea.
Price ext.
Catalog no.
Supplier
$0.99 $0.45 $0.55 $0.75 $0.39
$0.99 $1.80 $0.55 $0.75 $0.39
72442 37401 38623 40328 37196
JAMECO JAMECO JAMECO JAMECO JAMECO
$0.49 $0.10 $0.10 $1.05 $0.12 $0.15 $1.80 $0.26 $0.71 $1.33
$0.49 $0.40 $0.40 $1.05 $0.12 $0.15 $1.80 $0.52 $0.71 $2.66
104942 109575 117559 137859 114673 114681 P9924-ND P8009S-ND RGE300-ND DN41102-ND
JAMECO JAMECO JAMECO JAMECO JAMECO JAMECO Digikey Digikey Digikey Digikey
Total $54.36 Supplier contact information: Allied Electronics, Inc., http://www.alliedelec.com, 1-800-433-5700. B.G. Micro, 55 N. 5th St., Suite 125, Garland, TX 75040, 1-800-276-2206. Digikey, http://www.digikey.com, 1-800-344-4539. Jameco Electronics, http://www.jameco.com, 1-800-831-4242. JDR Microdevices, http://www.jdr.com, 1-800-538-5000. Mouser Electronics, http://www.mouser.com, 1-800-346-6873. Radio±Shack, http://www.radioshack.com.
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
Description
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
259
Table 3 List of equipment needed for asynchronous experiments (prices in FY2000 dollars) Description
Quantity
Price ea.
Catalog no.
Supplier
Multimeter Soldering Iron
1 1
$49.95 $12.95
177480 129040
Jameco Jameco
Total $54. Supplier contact information: Jameco Electronics, http://www.jameco.com, 1-800-831-4242.
subsequent ones. The proposed experiments utilize a relatively inexpensive set of components and a single-board microcontroller and culminate in the construction of an autonomous vehicle. The authors expect that the asynchronous experiments will have the following bene®ts: 1. They will enable the introductory course to be oered on-line without compromising the quality of the educational experience compared with the on-ground course. 2. They will relieve the pressure of scheduling and stang of a physical laboratory. 3. They will encourage exploration and tinkering that might otherwise not occur due to limited time scheduling in the physical lab. 4. They will provide students with a set of tools that can be used in subsequent classes and projects. Appendix A. Parts lists for asynchronous Mechatronics experiments See Table 1. Appendix B. Parts lists for the MAD board See Table 2. Appendix C. Other equipment needed for asynchronous experiments See Table 3. References [1] Seely BE. The other re-engineering of engineering education, 1900±1965. Journal of Engineering Education 1999;88(July 1999):285±94. [2] Hanson D, Maushak NJ, Schlosser CA, Anderson ML, Sorensen C, Simonson M. Distance education: review of the literature. 2nd ed. Research Institute for Studies in Education, Iowa State University, 1996.
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[3] Ashley S. Getting a hold on mechatronics. Mechanical Engineering 1997;119:60±3. [4] Sano A. Going the distance. ASEE Prism 1999. [5] Paterson KG. Student perceptions of internet-based learning tools in environmental engineering education. Journal of Engineering Education 1999;88:295±304. [6] Paterson KG. The Chronicle of Higher Education, 1997. [7] World Lecture Hall, http://www.utexas.edu/world/lecture/me/. [8] ABET (Accreditation Board for Engineering and Technology, Inc). Engineering criteria 2000. 3rd ed. In: Engineering Accreditation Commission, Baltimore, MD, Pub. No. 98AB-7a; 1998 http:// www.abet.org/EAC/eac2000.html. [9] Felder RM, Silverman LK. Learning and teaching styles in engineering education. Engineering Education 1988;78:674±81. [10] Carryer JE. The design of laboratory experiments and projects for mechatronics courses. In: Workshop on mechatronics education. Stanford University, 1994. p. 18±23. [11] Furman BJ, Hsu TR, Wang JC, Barez F, Tesfaye A, Hsu P, Reischl P. Laboratory development for mechatronics education. In: Proceedings of the ASEE Annual Conference, Washington, DC, Session 1626; 1996. [12] Wang JC, Furman BJ, Hsu TR, Tesfaye A, Hsu P, Reischl P, Barez F. Mechatronics laboratory development at San Jose State University. In: Proceedings of Mechatronics '96, California Polytechnic State University, San Luis Obispo, Industrial and Manufacturing Engineering Department, 1996. p. 168±176. [13] Judge supports CFA and students' case for rights of disabled at SFSU. California Faculty, 1999. [14] Furman BJ. ME 106 course information, 2000 http://www.engr.sjsu.edu/bjfurman/courses/ME106/. [15] Martin FG. The handy board technical reference, November 15, 2000. http://handyboard.com/ techdocs/hbmanual.pdf. [16] Green M. The BOTBoard 2, 1995. http://www.rdrop.com/users/marvin/download/bb2man6.pdf. [17] Hagler MO, Mehrl D. A PC with sound card as an audio waveform generator, a two-channel digital oscilloscope and a spectrum analyzer. IEEE Transactions on Education, (currently in review).
Asynchronous hands-on experiments for Mechatronics education Burford J. Furman a
a,*
, Gregory P. Hayward
b
Department of Mechanical and Aerospace Engineering, San Jos e State University, San Jos e, CA 95192-0087, USA b Caspian Networks, San Jos e, CA 95134, USA
Abstract There has been great interest and eort at many engineering educational institutions to introduce on-line, or ``asynchronous'' courses. However, at the present time, the vast majority of on-line or distance education courses lack any hands-on activities that require the manipulation of physical artifacts or physical experimentation. This paper describes a series of hands-on Mechatronics experiments associated with an introductory Mechatronics course that could be done ``anytime, anywhere'' (asynchronously). The experiments are based on a relatively inexpensive ``kit'' of components and a single-board microcontroller. Ó 2002 Published by Elsevier Science Ltd.
1. Introduction The last two decades in the 20th century have been a period of rapid change in engineering education. Three notable developments have been the ``re-engineering'' of engineering education to include a better balance between analytical engineering science and concrete, hands-on engineering practice [1], the explosion of distance education opportunities particularly through the Internet [2], and the emergence of Mechatronics curricula in US institutions [3]. There has been great interest from many engineering colleges around the world to implement on-line courses over the Internet for courses in degree programs and for continuing education [4,5]. In fact, a study on Distance Education for all types of education found that by fall 1998, 90% of all institutions with 10,000 students or
*
Corresponding author. Tel.: +1-408-924-3817; fax: +1-408-924-3995. E-mail address: [email protected] (B.J. Furman).
0957-4158/02/$ - see front matter Ó 2002 Published by Elsevier Science Ltd. PII: S 0 9 5 7 - 4 1 5 8 ( 0 1 ) 0 0 0 6 5 - 4
252
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
more and 85% of institutions with enrollments between 3000 and 10,000 were expected to oer at least some kind of Distance Education courses [6]. These ``Distance Ed'' or ``asynchronous'' courses as they are sometimes called are attractive for a variety of reasons: · Students can take the course at their convenience rather than having to go to class at a predetermined time and location. · Students can proceed through the course material at their own pace. · A wider pool of students can be reached than is possible by traditional means. · Course materials can be more easily adapted to facilitate access by the disabled. · The Internet oers unique capabilities for multimedia instruction, collaboration, and interactivity [5]. However, at the present time, the vast majority of on-line or distance education courses lack any hands-on activities that require the manipulation of physical artifacts or physical experimentation (see for example the courses in various engineering disciplines at the World Lecture Hall web site [7]). This is a logical result, because courses that are mostly conceptual are the easiest to adapt from a traditional classroom method of delivery to an asynchronous format. But, hands-on experience is a vital ingredient of any high-quality engineering program. Some reasons why hands-on experience is so important are: · Students need to be exposed to the practice of engineering in addition to engineering science. · Engineering graduates must be able to ``design and conduct experiments, as well as analyze and interpret data'' [8]. · Students need to become familiar with the instruments and equipment common in engineering practice for subsequent work in industry or advanced study. · A large percentage of engineering students are visual, sensing, and active learners [9], and it is necessary for them to see, touch and feel things before they can fully process engineering concepts. There has also been signi®cant activity in the last decade to revise engineering curricula to include more design and concrete engineering practice rather than just engineering science [1]. This has particularly been the case in the development of freshmen engineering courses, where emphasis has been given on engaging students in engineering through problem-solving and hands-on design projects from the beginning of their program rather than at their senior year. On the other hand, most on-ground courses that provide signi®cant hands-on experience have an associated physical laboratory. This is particularly true of courses in Mechatronics [10±12]. Physical laboratories, however, pose some dicult challenges in many engineering curricula: · They require relatively large amounts of limited, physical space in a building. · Laboratory equipment is expensive to purchase, maintain, and upgrade. · They can be expensive to run, because of the relatively high number of contact hours associated with laboratory sections. · Many laboratory spaces, despite the eort and cost it takes to put them together, end up being grossly underutilized. · Existing facilities may not allow full access for handicapped individuals [13].
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
253
Because courses that provide signi®cant hands-on experience usually require a physical laboratory, there is a fundamental mismatch with oering them as distance education courses. This is a major barrier toward oering, for example, a complete on-line degree program of equivalent quality to a traditional on-ground program. Thus, in light of the desirability of hands-on experiences (especially for Mechatronics) and the challenges facing their incorporation in the curriculum, the authors see an opportunity to improve the current state of aairs by developing hands-on experiences for an introductory course in Mechatronics that do not require a physical laboratory, but can be carried out by students ``anytime, anywhere'' (asynchronously).
2. Background and approach The authors are developing a series of asynchronous Mechatronics experiments to be piloted in ME 106, Fundamentals of Mechatronics, at San Jose State University. ME 106 is a required course for all mechanical engineering students that seeks to expose them to analog electronics, digital electronics, sensors and transducers, actuators, and microprocessors. Lectures are intended to provide the student with foundational concepts in mechatronics and practical familiarity with common elements making up mechatronic systems. Laboratory experiments are designed to give the student hands-on experience with components and measurement equipment used in the design of mechatronic products [14]. The three prerequisites for the course are: Computer Applications (i.e., computer programming), Introduction to Circuit Analysis, and Dierential Equations. Most students take ME 106 in their junior year. Presently, there are 12 experiments in ME 106, and students perform one per week, in a 3-h laboratory period. Details of these experiments are available on the Internet [14]. The experiments are performed in a well-equipped laboratory consisting of ten work stations each with its own set of test and measurement equipment and networked PC [11]. The overall educational goals for the asynchronous experiments are essentially the same as for those conducted in the physical laboratory. Further, some new approaches will be taken to decouple the learning environment from a dedicated laboratory on campus and to more tightly integrate the learning experience. For example, a ``kit'' of relatively inexpensive, readily available components has been de®ned which the student will use to perform the laboratory experiments at a location and time of his or her choosing. The kits can be purchased from the Department or assembled by the student from local electronics stores such as Radio Shack. The kit components are listed in Appendix A. The student will build or purchase (from the Department) a single-board microcontroller, designed by the authors, called the ``Mechatronics for Autonomous Devices (or MAD) board. The MAD Board is based on the Motorola 68HC11
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microcontroller, and borrows design and operational features from the MIT Handy Board [15] and Marvin Green's BOTBoard 2 [16]. This approach has been taken for several reasons: · The MAD Board is relatively inexpensive, about $50 for its components. · It can be programmed with Interactive C (IC) or by using other freeware or commercial C compilers. · It can control DC motors and servos directly from the board, and it has an 8-bit ADC converter as part of the 68HC11 chip. · It is relatively simple to build, debug, and maintain. The parts for the MAD Board are listed in Appendix B. It will be assumed that the student will have or can borrow a personal computer with a sound card. Hagler and Mehrl, have pioneered the use of a PC sound card as an audio waveform generator and oscilloscope for measurements on simple signal processing circuits [17]. A similar approach will be used in one of the asynchronous experiments to enable a student to explore the behavior of RC ®lters for ®ltering noisy signals from sensors. The student will also need a multimeter and soldering iron. Approximate costs for these items and an example supplier are listed in Appendix C. 3. Asynchronous experiments The asynchronous experiments are designed to be integrative, and they culminate with the student building an autonomous vehicle that must negotiate a prede®ned ``playing ®eld'' and that will score points by manipulating ping±pong balls. There are 11 ``experiments''. Besides the ®rst two, each involve the use of the MAD Board and introduce the student to fundamental concepts such as Ohm's law, digital input/output, ADC conversion, use of transistors to control power, etc. The sequence is: 1. MAD Board Build (week 1). 2. MAD Board Build (week 2). 3. MAD Board Familiarization. 4. RC Filters and Op-amps. 5. On/O Motor Control. 6. PWM Motor Speed Control. 7. Pulse Accumulation and Speed Measurement. 8. Autonomous Vehicle Power Train Bring-up. 9. Autonomous Vehicle Sensor Bring-up. 10. Autonomous Vehicle Integration. 11. Autonomous Vehicle Performance Demo. The student will be strongly encouraged to build his or her own MAD Board during the ®rst two weeks. Not only will the student learn to solder, but also he or she will gain a deeper understanding of how the board is laid out and how it functions. We anticipate that we will need to oer demonstrations and/or create tutorial resources to help students learn to solder and use a multimeter.
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In the third experiment, the student will verify voltage division and Ohm's law, explore the resistance behavior of photoresistors, and get familiar with the ADC system of the 68HC11 by using it to determine the voltage in a resistive network. The learning goal for this experiment is to become familiar with a multimeter, solderless breadboard, resistors, photoresistors, and how to write a program to control the MAD Board. In the fourth experiment, the student will explore the characteristics of RC ®lters using a PC sound card following the approach of Hagler and Mehrl [17]. Operational ampli®ers and the concept of signal ampli®cation will be explored. The student will build an ampli®er to maximize the input range of the ADC on the MAD Board and write a program to capture an AC signal. The ®fth experiment will have the student become familiar with the digital input/ output (IO) capability of the MAD Board and explore the use of transistors to control power. The student will use the ADC port on the MAD Board with an analog sensor and the digital IO port with transistors to turn a motor on or o and control the direction of rotation depending on the output from the sensor. The sixth experiment will have the student explore Pulse Width Modulation (PWM) and how it can be used to control the speed of a motor. The student will write a program for the MAD Board to control the speed of a DC motor depending on the voltage set by a potentiometer. In the seventh experiment, the student will explore how to use the MAD board to count pulses and determine the speed of a rotating wheel. The seventh, eighth, and ninth experiments will focus on the major aspects of bringing up the student's autonomous device. The ®nal experiment will be a demonstration of the vehicle's performance on a prede®ned playing ®eld. Students will be required to submit their vehicle to the instructor three days prior to the performance demonstration. 4. Implementation plan The MAD Board and asynchronous experiments are under development. By the end of August 2000, the layout and fabrication of a prototype MAD Board and details for experiments 3 and 4 are expected to be completed. The remaining experiments will be developed during the fall of 2000. The authors hope to begin piloting the experiments during the fall of 2000. 5. Summary and conclusions A series of introductory, hands-on Mechatronics experiments are under development that do not require a physical laboratory in which to perform them. The experiments will introduce the student to fundamental concepts in Mechatronics, yet do so at the pace and convenience of the student. The experiments are designed to be integrative so that knowledge gained in earlier experiments can be applied in
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Table 1 Parts list of components needed for asynchronous experiments (prices in FY2000 dollars) Description
Quantity Value
Switching diodes 100 X resistor 5 mm 500 mA fuse 5 mm fuse holder Phone jack
4 1 1 1 2
1N4148 100 X 500 mA Stereo
Double binding posts, dual 2 banana ABS Speedy Box 1 6 3:5 1:9 in. Stereo 1/8 in. phone cables 2 Solderless breadboard 1/2 W shaft pot Hookup wire, red Hookup wire, black Hookup wire, green LED, green LED, red CdS Photoresistor DPDT mini toggle switch
1 1 3 3 3 2 2 1 1
SPST mini toggle switch 1 k 1/4 W resistor 10k 1/4 W resistor 0.22 lF capacitor 2N3904 NPN transistor TIP120 Power Darlington IRF510 Power MOSFET Opto Interrupter module L293D Push-Pull Driver 5 V DPDT relay
1 6 2 1 2 4 2 2 1 1
DC motor
2
10 K ft. 22 AWG ft. 22 AWG ft. 22 AWG T1, 3 mm T1, 3 mm 10±100k DPDT on±o±on SPST on±o 1K 10 K 0.22 lF 2N3904 TIP120 IRF510 L293D 5 V, 120 VAC 1A 1.5±3 V DC
Price ea.
Price ext. Catalog no.
Supplier
$0.04 $0.05 $0.02 $0.75 $1.01
$0.16 $0.05 $0.02 $0.75 $2.01
36038 R100 102040 150463 274-249
$2.49
$4.98
125196
Jameco JDR Jameco Jameco Radio Shack Jameco
$2.95
$2.95
18892
Jameco
$3.99
$7.98
42-2387
$11.95 $0.99 $0.03 $0.03 $0.03 $0.11 $0.11 $0.55 $1.09
$11.95 $0.99 $0.09 $0.09 $0.09 $0.22 $0.22 $0.55 $1.09
20757 29081 36863 36804 36839 LED100 LED101 136047 26358
Radio Shack Jameco Jameco Jameco Jameco Jameco JDR JDR Jameco Jameco
$1.09 $0.05 $0.05 $0.23 $0.06 $0.59 $0.46 $0.85 $2.00 $2.49
$1.09 $0.30 $0.10 $0.23 $0.12 $2.36 $0.92 $1.70 $2.00 $2.49
76523 R1k R10k M.22 38359 32993 273-0233 H21A1QT-ND 511-L293D 139977
Jameco JDR JDR JDR Jameco Jameco Allied Digi-Key Mouser Jameco
$1.29
$2.58
273-223
Radio Shack
Total $48.07 Supplier contact information: Allied Electronics, Inc., http://www.alliedelec.com, 1-800-433-5700. B.G. Micro, 55 N. 5th St., Suite 125, Garland, TX 75040, 1-800-276-2206. Digikey, http://www.digikey.com, 1-800-344-4539. Jameco Electronics, http://www.jameco.com, 1-800-831-4242. JDR Microdevices, http://www.jdr.com, 1-800-538-5000. Mouser Electronics, http://www.mouser.com, 1-800-346-6873. Radio±Shack, http://www.radioshack.com.
Table 2 Parts list for MAD board (prices in FY2000 dollars) Description
Quantity Value
PC board
1 V
Price ea.
Price ext.
$8.50
$8.50
Catalog no.
Supplier
2 7 2 1 4 4
47 lF 0.1 lF 22 pF 100 lF 22 lF 10 lF
C1, C2 C3±C9 C10, C11 C12 C13, C14, C15, C16 C17, C18
$0.06 $0.15 $0.09 $0.06 $0.07 $0.04
$0.12 $1.05 $0.18 $0.06 $0.28 $0.16
31114 25523 81533 93761 158326 29891
JAMECO JAMECO JAMECO JAMECO JAMECO JAMECO
Resistors 5% precision 5% precision 5% precision Resistor Pack SIP Resistor Pack SIP Resistor Pack SIP
1 1 1 2 1 2
10 K 10 meg 470 X 10 K, 6 pins 5 RES. 1 K, 8 pin 4 RES. 47 K 10 pin 9 RES.
R1 R2 R3 R4, R5 R6 R7, R8
$0.27 $0.27 $0.27 $0.25 $0.32 $0.25
$0.27 $0.27 $0.27 $0.50 $0.32 $0.50
10MQBK-ND 10KQBK-ND 470QBK-ND 773061103-ND 773083102-ND 98087
Digikey Digikey Digikey Digikey Digikey JAMECO
IC's 6811 microprocessor Octal D-type ¯ip/¯op tri-state 32 K static CMOS RAM Triple 3-input NAND 3±8 decoder/multiplexer RS232 converter Quad 2-input Schmitt NAND Transparent Octal D-type Latch Motor driver Octal D-type ¯ip/¯op edge-trig 5 V, 1 A regulator
1 1 1 1 1 1 1 1 1 1 1
MC68HC11A1FN 74HC573 62256-32K 100 74HC10 74HC138 MAX232 74HC132 74HC373 L293 74HC374 7805T
U1 U2 U3 U4 U5 U6 U7 U8 U9 U10 U11
$10.00 $0.79 $2.25 $0.19 $0.35 $3.98 $0.35 $0.45 $5.00 $0.45 $0.29
$10.00 $0.79 $2.25 $0.19 $0.35 $3.98 $0.35 $0.45 $5.00 $0.45 $0.29
68HC11 46076 62256LP-10 45233 45330 MAX232EWE-ND 45321 45831 296-2128-5ND 45858 51262
B.G. MICRO JAMECO JAMECO JAMECO JAMECO Digikey JAMECO JAMECO Digikey JAMECO JAMECO
V V V
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
Capacitors Mini Radial 'lytic, 50 Monolithic Ceramic Monolithic Ceramic Mini Radial 'lytic, 25 Mini Radial 'lytic, 35 Mini Radial 'lytic, 50
Reference
257
258
Table 2 (Continued) Quantity Value
Sockets 52 PIN PLCC Socket 16 pin DIP 20 pin DIP 28 pin DIP 14 pin DIP
1 4 1 1 1
52 16 20 28 14
Miscellaneous Serial Connector 3 pin Headers 4 pin Headers 8 MHz Crystal Red LED Green LED Speaker Push Button Switch Polyswitch Fuse Inductor
1 4 4 1 1 1 1 2 1 2
DB-9 3 pin Headers 4 pin Headers 8 MHz Crystal Red LED Green LED Speaker Switch momentary Fuse 1uH
Reference
PIN PLCC. pin DIP pin DIP pin DIP pin DIP DB9F Pwr., Bat., S1-S4, J1, J2 AD0-AD3, SCI X1 LED1 LED2 PZ S1, S2 F1 L1
Price ea.
Price ext.
Catalog no.
Supplier
$0.99 $0.45 $0.55 $0.75 $0.39
$0.99 $1.80 $0.55 $0.75 $0.39
72442 37401 38623 40328 37196
JAMECO JAMECO JAMECO JAMECO JAMECO
$0.49 $0.10 $0.10 $1.05 $0.12 $0.15 $1.80 $0.26 $0.71 $1.33
$0.49 $0.40 $0.40 $1.05 $0.12 $0.15 $1.80 $0.52 $0.71 $2.66
104942 109575 117559 137859 114673 114681 P9924-ND P8009S-ND RGE300-ND DN41102-ND
JAMECO JAMECO JAMECO JAMECO JAMECO JAMECO Digikey Digikey Digikey Digikey
Total $54.36 Supplier contact information: Allied Electronics, Inc., http://www.alliedelec.com, 1-800-433-5700. B.G. Micro, 55 N. 5th St., Suite 125, Garland, TX 75040, 1-800-276-2206. Digikey, http://www.digikey.com, 1-800-344-4539. Jameco Electronics, http://www.jameco.com, 1-800-831-4242. JDR Microdevices, http://www.jdr.com, 1-800-538-5000. Mouser Electronics, http://www.mouser.com, 1-800-346-6873. Radio±Shack, http://www.radioshack.com.
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
Description
B.J. Furman, G.P. Hayward / Mechatronics 12 (2002) 251±260
259
Table 3 List of equipment needed for asynchronous experiments (prices in FY2000 dollars) Description
Quantity
Price ea.
Catalog no.
Supplier
Multimeter Soldering Iron
1 1
$49.95 $12.95
177480 129040
Jameco Jameco
Total $54. Supplier contact information: Jameco Electronics, http://www.jameco.com, 1-800-831-4242.
subsequent ones. The proposed experiments utilize a relatively inexpensive set of components and a single-board microcontroller and culminate in the construction of an autonomous vehicle. The authors expect that the asynchronous experiments will have the following bene®ts: 1. They will enable the introductory course to be oered on-line without compromising the quality of the educational experience compared with the on-ground course. 2. They will relieve the pressure of scheduling and stang of a physical laboratory. 3. They will encourage exploration and tinkering that might otherwise not occur due to limited time scheduling in the physical lab. 4. They will provide students with a set of tools that can be used in subsequent classes and projects. Appendix A. Parts lists for asynchronous Mechatronics experiments See Table 1. Appendix B. Parts lists for the MAD board See Table 2. Appendix C. Other equipment needed for asynchronous experiments See Table 3. References [1] Seely BE. The other re-engineering of engineering education, 1900±1965. Journal of Engineering Education 1999;88(July 1999):285±94. [2] Hanson D, Maushak NJ, Schlosser CA, Anderson ML, Sorensen C, Simonson M. Distance education: review of the literature. 2nd ed. Research Institute for Studies in Education, Iowa State University, 1996.
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[3] Ashley S. Getting a hold on mechatronics. Mechanical Engineering 1997;119:60±3. [4] Sano A. Going the distance. ASEE Prism 1999. [5] Paterson KG. Student perceptions of internet-based learning tools in environmental engineering education. Journal of Engineering Education 1999;88:295±304. [6] Paterson KG. The Chronicle of Higher Education, 1997. [7] World Lecture Hall, http://www.utexas.edu/world/lecture/me/. [8] ABET (Accreditation Board for Engineering and Technology, Inc). Engineering criteria 2000. 3rd ed. In: Engineering Accreditation Commission, Baltimore, MD, Pub. No. 98AB-7a; 1998 http:// www.abet.org/EAC/eac2000.html. [9] Felder RM, Silverman LK. Learning and teaching styles in engineering education. Engineering Education 1988;78:674±81. [10] Carryer JE. The design of laboratory experiments and projects for mechatronics courses. In: Workshop on mechatronics education. Stanford University, 1994. p. 18±23. [11] Furman BJ, Hsu TR, Wang JC, Barez F, Tesfaye A, Hsu P, Reischl P. Laboratory development for mechatronics education. In: Proceedings of the ASEE Annual Conference, Washington, DC, Session 1626; 1996. [12] Wang JC, Furman BJ, Hsu TR, Tesfaye A, Hsu P, Reischl P, Barez F. Mechatronics laboratory development at San Jose State University. In: Proceedings of Mechatronics '96, California Polytechnic State University, San Luis Obispo, Industrial and Manufacturing Engineering Department, 1996. p. 168±176. [13] Judge supports CFA and students' case for rights of disabled at SFSU. California Faculty, 1999. [14] Furman BJ. ME 106 course information, 2000 http://www.engr.sjsu.edu/bjfurman/courses/ME106/. [15] Martin FG. The handy board technical reference, November 15, 2000. http://handyboard.com/ techdocs/hbmanual.pdf. [16] Green M. The BOTBoard 2, 1995. http://www.rdrop.com/users/marvin/download/bb2man6.pdf. [17] Hagler MO, Mehrl D. A PC with sound card as an audio waveform generator, a two-channel digital oscilloscope and a spectrum analyzer. IEEE Transactions on Education, (currently in review).