Signal Processing - May 2017 - 77

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divider uses a photoresistor, which
can vary from 27,000 X to 200,000 X,
a sufficient range to function as a
switch. Following the voltage divider,
a simple positive-negative-positive
bipolar junction transistor is implemented in common collector mode
to increase current flow. Finally, the
output consists of an array of LEDs
connected in a series to serve as a
light source.
For those students who wish to work
on more advanced designs, additional modules are available.

Experiment 1-On/Off toggle switch
An additional toggle switch can be
added to break the connection from the
battery source to the rest of the circuit.
This can help tremendously in saving
battery life.

Experiment 2-Fine-tuning with a potentiometer
A potentiometer is used to replace the
100,000 resistor in the circuit. Varying
the impedance on this potentiometer
adjusts the sensitivity of the light
switch. Students get a schematic, the
materials for the project, and a short
lesson on how the electronic circuit
works. Figure 5(a) displays the students working in the lab to build the
night-light and (b) shows the schematic
of the project.

On-going endeavors
Our ongoing work builds upon what we
have learned from past outreach efforts as well as the research base in

engineering design in their instruction,
and we will work with school counselors on their efforts to advise students on
pre-engineering coursework and the
diversity of engineering careers. The
professional development workshops
will be modeled upon previous similar
offerings at SBU. With external support, summer STEM education workshops have been offered for elementary
teachers, middle school mathematics
and science teachers, and high school
chemistry and physics teachers [74].
Our theoretical model reinforces our
emphasis on professional development
in authentic settings for both science
teachers and school counselors. In
addition, the teacher workshops will
incorporate ASEE's Standards for
Preparation and Development for
Teachers of Engineering [75], which
include literacies in engineering
design, engineering careers, and engineering and society.
The science teacher workshops will
educate teachers to incorporate engineering aspects of the NGSS in their
New York State-standardized science
curricula. Twenty-four participants will
attend each four-part workshop, with
each teacher impacting approximately
150 students per academic year. We
expect to recruit four cohorts during the
first year with expansion in subsequent
years. Participants will build their engineering skills by applying design principles while teaching science content and
process. Each cohort will be immersed
in a program of mutually reinforcing

engineering education. These projects
are to be implemented in the coming
year with a pilot design phase and
accompanying research components to
measure impacts empirically. This
allows us to make formative changes
and maximize programmatic effectiveness for scaling the following year. Our
projects are designed to attract, retain,
and support precollege students in engineering. We plan to educate school
counselors and science teachers on the
diversity of engineering career pathways as well as engineering disciplinary knowledge and process skills. By
targeting these two groups, we will
build capacity and competence for
studying engineering, a profession that
contributes to global technological
advancement. The overarching goals
are twofold. Engineering should not be
viewed as a separate discipline but rather an essential component of students
scientific literacy, complementing traditional science content with structured
opportunities to design solutions to scientific problems. Furthermore, the field
of engineering will be diversified with
students from an untapped talent pool
to contribute to the global competitiveness of the United States.

Counselors and teachers
Our work with science teachers and
school counselors began in 2017, with
our previous work developing engineering activities for students as the starting
point for professional development. We
will train science teachers to incorporate

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LDR

+9v

+9v
R4
3+ 7 1
6
2 LM741
-
5
4 8

Q1
R5

R1-100-10 kΩ Pot
R2-47 kΩ
R3-47 kΩ
R4-22 kΩ (Adjusts Hysteresis)
R5-1 kΩ
R6-470 Ω (LED Brightness)
Q1-NPN BJT
R6

Stony Brook University
Ambient Light Activated LED Module
(a)

(b)

Figure 5. The night-light activity at the 2015 After-School Engineering Program: (a) students soldering the circuit and (b) the schematic of the project.
IEEE Signal Processing Magazine

May 2017

Table of Contents for the Digital Edition of Signal Processing - May 2017