June 20, 2010
June 20, 2010
June 23, 2010
Computers in Education
15.139.1 - 15.139.9
An Application-based Approach to Introducing Microcontrollers to First-year Engineering Students
This paper describes a microcontroller-based learning module designed to introduce first-year engineering and engineering technology students to a variety of topics in electrical and computer engineering. The module comprises a series of lectures and laboratory exercises in which the students learn basic computer organization and architecture, assembly language, and programming tools and use this knowledge to measure and control the climate in a prebuilt foam house. The students control such elements as heaters, thermoelectric coolers, and an attic fan with the goal of maximizing energy efficiency.
Assessment of the success of the learning module was performed using exams, laboratory reports, homework, and student surveys. The results of the assessment strongly suggest that the students successfully learned a substantial amount of information about binary and hexadecimal number systems, digital electronics, and computer organization and architecture and programming.
In this paper we describe the use of a series of simple microcontroller laboratory exercises designed to introduce first-year students to a variety of topics in electrical and computer engineering. While the subject of microcontrollers is usually reserved for more advanced students we have found that by limiting the instruction set to a small number of relatively simple instructions and selecting a user-friendly design environment such as Freescale’s CodeWarrior, students can be successfully introduced to topics such as basic computer organization and architecture, programming models, and control theory.
The lectures and laboratory exercises form a complete teaching module centered around a microcontroller-based “smart” house. The students use a low-cost microcontroller to measure status and control functions such as temperature in the house. The house is essentially a foam box with electric heater, thermoelectric “air conditioner” and an attic vent fan. After an introduction to basic microcontroller functionality and a small subset of the microcontroller’s instruction set, the students learn to measure inside and outside temperatures and actuate the cooling and heating elements. They then program the microcontroller to implement a conventional hysteresis-based control system and measure how the high/low set-points impact energy usage in both heating and cooling modes. Next, the students reverse the thermoelectric cooler and compare the efficiency of heat pump heating to that of conventional resistive heating as a function of the difference between inside and outside temperatures. Finally, the students develop their own algorithms to minimize energy consumption. These can include such features as use of the attic fan, varying the sampling time or size of the hysteresis loop, proportional control of the heating or cooling elements, or mixing the heat pump with conventional heating.
The exercises provide a simple hands-on introduction to computer organization and architecture, control theory, and cost tradeoffs. They also build on skills typically acquired in an introductory
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