Transcript VIP_NI_posterx - Purdue College of Engineering

Technologies for Neuroimaging
Department of Electrical and Computer Engineering
Undergrad Team: Aaron Rosenfeld, Shawn Nagar, Anshul Panwar, Abylaikhan Alip, Ruslan Nurimbetov
Professor: Thomas Talavage
GENERAL GOAL
ORIGINAL CONTROLLER DESIGN
The mechanical design was altered to better suit 3D
printing capabilities and requirements. The fiber optic
transceiver was rebuilt, tested, and revised with
updated schematics. The Tiva (microcontroller) was
programmed to represent the receiver’s output voltage
as numerical data accessible by the host device.
Functional Magnetic Resonance Imaging (fMRI) is a way
of measuring localized brain activity. It requires the
subject to remain still while often interacting with an
external stimulus. One effective way to stimulate higher
cognitive function is using video games. However due to
the high magnetic field present during testing, there
cannot be any metallic objects close to the subject. A
typical controller is not a viable way for a subject to play
games during the fMRI. A completely nonmetallic
controller is desired to help stimulate the brain for
complex sensorimotor investigation. A plastic and fiber
optic controller is being developed to meet these
requirements.
FUTURE WORK
A custom 3D printed model with better ergonomics
needs to be designed. An opto-mechanical interface
must be integrated into the joystick design to relate
light attenuation to axis position. The transceiver circuit
design should be optimized for a single voltage rail. The
microcontroller should be configured as a USB PID
(physical interface device) by the host device.
PREVIOUS WORK
The prototype was based on a button based user input
system which consisted of custom made optical sensors
and microcontroller design.
The prototype had some major issues:
• Extended usage led to misalignment and incorrect
button presses
• Not easily reproducible
• Obsolete components
• Bulky
The emergence of 3D printing has expanded options for
mechanical designs. Previous teams have updated circuit
schematics, modified mechanical designs, and mapped
the relationship between optical attenuation and analog
receiver voltage.
CURRENT WORK
COMPONENTS
PROTOTYPE DESIGNS
Sensors and Controller
• TI Tiva TM4C123G LaunchPad
• Digital Fiber optic Receivers (AFBR-2624Z )
• Analog Fiber optic Receivers (SFH250V)
• Fiber optic transmitters (AFBR-1624X)
• 1mm fiber optic cable
Controller Case
• External shell
• Base mount
(Left)The original joystick design relied on
earlier plastic manufacturing processes,
requiring pieces to be designed in halves
and cast in break-out molding.
(Right) The resulting assembly has poor
mechanical stability, and requires precision
beyond the capabilities of consumer-grade
3D printers; axis holes must be machined
after printing.
Revised mechanical design
gimbal (Top) and housing
(Bottom) present a more
mechanically stable design, and
have greater tolerance for hole
placement in 3D printing.