Stepper Motor Control with a Microprocessor for Laser Beam Data Analysis
Colin Gregory, Erkan Gulturk
Bridgewater State University, Bridgewater MA 02325
Mentor: Edward F. Deveney Ph.D
Abstract
Methods
Current Status
Our goal is to construct a mechanism that allows us to
precisely launch laser light through a fiber optic cable and
measure the collimated output. We currently have no
measurement equipment with fine enough resolution to
sample the angular intensity of the beam. Using an Arduino
UNO microcontroller, 5V Unipolar Stepper Motor, and proper
gearing we can control the fiber optic outputs angular
movement precisely. The code for our stepper motor was
written in the open source Arduino environment. We are
continuing our effort to set up the mechanical system that will
rotate the platform holding the fiber optic output.
Within the stepper motor are a series of magnets and
electromagnetic coils that can be charged in such a fashion as to
move the stepper motor in small increments. The motor can
make full steps, half steps, or a combination of both. The
diagrams below display this concept.
With the ability to control the stepper motor using code
written to the Arduino, we will continue our efforts to set up a
mechanical system that will optimize our precise control of the
laser beam output. Our options include using a Tamiya High
Efficiency worm gear box (below) that offers both 216:1 and
336:1 gear ratios.
Materials
Our second option includes a simple gear transfer using an
inexpensive gear set that can be seen below.
We are attempting to create a stepper motor driven platform
that allows precise angular control of the laser output. Below
is an image of the fiber optic laser set-up.
The image below shows the circuitry for our stepper motor. We
are using a 9V battery in combination with a 5V regulator for
power. We powered the stepper motor from a separate power
source using a powered breadboard.
The 5V Unipolar Stepper Motor makes 1.8°+/- 5% steps,
making 200 steps equivalent to one full rotation. A 216:1 ratio
would result in each step moving the output 0.008°. To reduce
error in the calculated angular displacement we would move
multiple steps before each output measurement.
Our 5V, 1A, 4-Phase Unipolar Stepper Motor and Arduino Uno
microcontroller were purchased from Jameco Electronics. The
Arduino is being used to control the stepper motor.
References
A 2004 Darlington Array was also used to properly transfer the
Arduino’s output to the stepper motor.
"12 Volt Unipolar Stepper Motor." Www.parrallax.com. Web. 3 Apr.
2012.
<http://dscl.lcsr.jhu.edu/wiki/images/9/98/Stepper_Motor_27964.pdf>.
Our code is written in the open source Arduino environment as
seen below.
"Arduino - StepperUnipolar." Arduino. Web.
<http://arduino.cc/hu/Tutorial/StepperUnipolar>.
4
Apr.
2012.
"Getting
Started
with
Arduino
(Make:
Projects)
[Paperback]." Amazon.com: Getting Started with Arduino (Make:
Projects) (9780596155513): Massimo Banzi: Books. Web. 2 Apr. 2012.
<http://www.amazon.com/Getting-Started-Arduino-MakeProjects/dp/0596155514>.
"Tamiya America Item #72004 | Worm Gear Box H.E." Tamiya America.
Web. 11 Apr. 2012. <http://www.tamiyausa.com/product/item.php?pro
duct-id=72004>.