Girls Flex Their Engineering Muscles at CMU

 Discovering Their Own Power in ECE

August 3, 2004

Electrical and Computer Engineering (ECE) faculty Gary Fedder and Diana Marculescu challenged over 40 high school girls to flex both their brain and arm muscles, teaching them to measure, process, and visualize the current produced when pumping their biceps. Part of the Society of Women Engineer's (SWE) annual Engineering Your Future (EYF) workshop for girls who have completed grades eight through eleven, the July 12-21 program brought more than 120 Pittsburgh public school students to campus for experiments in electrical and computer, biomedical, chemical, civil and environmental, materials science, and mechanical engineering, and engineering and public policy.

"Our goal is to have these inner city kids continue on to college, wherever they decide to go," said Hilda Diamond, EYF Administrator, SWE Advisor, and Associate Department Head of Biomedical Engineering (BME). This summer, SWE began to track how many of the EYF seniors continue their higher education in engineering.

Christal Banks from BME coordinated the event, which has been held since the early 1980's. Students are recommended by their counselors and science teachers, and sponsored by the Pennsylvania Space Grant Consortium, Duquesne Light, the Buhl Foundation, and the Grable Foundation.

"EYF was truly a learning experience and I'd recommend it to anyone," encouraged Stephanie Rozanski, a graduate of Brashear High School who decided to pursue ECE after enjoying the sessions. SWE awarded her a $500 scholarship; like many students in the group, she will be the first in her family to attend college.

"The hands-on experience really made all of the difference in the world," said Stephanie's mother, Jayne. Stephanie was accepted into Penn State University's college of engineering this fall and is already inspiring her younger sister, Krysten, who also came to EYF. To qualify for the award, a student must enroll in EYF for four summers-the end of eighth, ninth, tenth, and eleventh grades. She must submit her acceptance letter to a four year college to the EYF committee, showing that her major is in engineering, and that the EYF curriculum influenced her decision.

"EYF is a wonderful event to inspire high school girls to consider engineering as a college and career option. The work we put into making the event a success is well worth it," ECE and Robotics Professor Fedder remarked. His teaching assistants were ECE graduate student Sarah Bedair, post doctoral fellow Philippe Basset, and juniors Jay Patel and Jenna Fu.

"I really enjoyed this project; I learned a lot in the process and I loved working with the girls," said Fu, who developed the EMG lab and instruction guides. "I think it's a great way to expose them to engineering and all the things that are possible through it. Most students would not otherwise have this opportunity until they actually start college," she added.

This year's high school theme, "Make-up: Engineering the Human Body," led the girls in Fedder's class to discover their own power. Each team of two built an electromyogram (EMG) pre-amplifier circuit to measure the electrical current produced when they flexed their muscles. They stuck electrode sensors on their biceps and elbows and made the circuits using basic electrical engineering equipment, including operational amplifiers (op-amps), capacitors, and resistors, with a hardware prototyping board (protoboard) to connect the circuit to the ground wire and positive and negative power supplies.

By the end of the course, the participants, who told Fedder they had never used oscilloscopes before, were able to hook up a function generator to provide an input waveform from the circuit and view the signal's output using the oscilloscope, which displays voltage and current oscillations. They could also control differential amplifiers to compute the difference between two signals to filter out background noise, rejecting common-mode signals coming from the body (such as 60 cycle power noise).

Next, the attendees took the digital output signals from the sensors and processed it in Assistant Professor of ECE Diana Marculescu's computer engineering (CE) laboratory.

"I hope our CE lab session was fun and exciting for participating high school students! We tried to show them that computers can be used for more than just web-browsing or instant messaging," said Marculescu. ECE grad students Emil Talpes, Phillip Stanley-Marbell, Koushik Niyogi, and Natasa Miskov-Zivanov and juniors Han Chun Lim and Yanjing Li helped the girls, by demonstrating how to measure muscle fatigue, determine the number of calories burned when muscles are active, and find out whose muscles produce the most current.

The partners used a peripheral interface microcontroller (PIC) on the same board as the pre-amplifier circuit to process the data and send it over a serial interface to a PC, where it was collected in a file format readable by MATLAB's Simulink software package. Talpes, Stanley-Marbell, and Niyogi prepared the MATLAB scripts. Each EYF group analyzed and visualized various parameters for the captured signals with Simulink, noting that as their muscles fatigued, there was a change in the power spectrum of data collected from the electrodes. Using this power density spectrum, called a frequency domain analysis, they calculated how much their muscles fatigued over time. The exercise showed them that block diagrams can model such dynamic systems, including a frequency spectrum block for graphing the signals and a frequency spectrogram to view the data over time.

After filtering and processing the EMG signals, the girls used them to control a mechanical joint that simulates a prosthetic joint in Assistant Professor of Robotics Yoky Matsuoka's biomedical engineering module. Through the activity, they saw that biological signals can control engineering devices, such as advanced prosthetic devices that use a patient's own muscle signals to control a lost limb's movement.

Fedder began his lesson for girls entering ninth grade with a presentation about ECE. When he asked what a resistor does, Lindsay Forman, from Rogers Middle School for the Creative and Performing Arts (C.A.P.A.) piped up with the answer. Her section built an optical encoder wheel and hooked it up to a small direct current (DC) motor. She and her classmates measured the motor's speed and figured out how to encode the digital data and analyze the electrical waveforms on an oscilloscope.

Fedder's pupils also included Lindsay Hayes, Sarah Kunka, and Hannah Thyberg, who will all enter Schenley High School in the fall.

"We're learning a lot of new stuff that we never would have learned if we hadn't come. The hands-on activities make it more fun, so it's not just sitting in a classroom learning," explained Hayes. Her favorite part of the laboratory was seeing the finished product.

"We learned about the different kinds of engineering and what the different types of engineers actually do," said Kunka, who also attended a pre-engineering seminar at Carnegie Mellon in fourth grade.

"It's definitely worth it," reported Thyberg, of EYF, her first introduction to engineering. They are all are interested in coming back next year.

View the photo gallery.

Middle school students in Professor Fedder's Engineering Your Future ECE lab hooked up an optical encoder wheel to a direct current (DC) motor.

Assistant Professor of ECE Diana Marculescu and Hilda Diamond, EYF Administrator, with ECE student assistants Yanjing Li and Emil Talpes.

Assistant Professor of ECE Diana Marculescu shows high school girls how to process electromyogram signals.

Professor of ECE and Robotics Gary Fedder teaches the girls in the ECE lab.