Steel Bar Final Presentation MAE 435 Maureen Loughran Gregory Ragosta Christina Felarca Adham Sohby

Objective  To develop a steel bar prototype that will allow doctors to know the appropriate time to remove the bar from the patient  Prevents chest wall from regressing back to its original state  Real Proof of Concept prototype and Ideal Model  Have the ability to gather this information outside of the body, wirelessly, to provide the least amount of discomfort for the patient.

Overview Pectus Excavatum  Deformity of the chest and ribs  Commonly treated by the Nuss Procedure  4% of PE patients must undergo the surgery again due to premature removal of bar 16-Year Old Boy With Severe Pectus Excavatum

Overview cont’d Radio Frequency Identification (RFID)  Miniature device that can wirelessly transfer data from a RFID reader  Takes in a radio signal and transmits back out the stored information on the tag  Semi-passive RFID Wireless Identification and Sensing Platform (WISP)  Developed by Intel  Powered solely by RF absorbed by antenna Wisp Functional Diagram

Overview cont’d Intel Strain Gauge Solution  Strain gauge PCB has to be built to interface WISP with strain  Wheatstone Bridge  Amplifier

Our Solution  Real Proof of Concept Model  Place 1 strain gauge on the surface of the bar  Using Intel’s strain gauge solution, we can connect the strain gauges to the WISP via a Wheatstone bridge and amplifier  The WISP will interface with the reader (outside of the patient) and report the data using WISP’s reader software  Ideal Model  Ideal model will have 2 strain gauges with all the components built into the bar itself (to cancel noise and tension/compression)

Theoretical Design  AutoCAD model

Theoretical Design

Equipment Setup  Stainless Steel Bar (9 in.)  E=192 Gpa, v=0.265  Impinj Speedway 1000 RFID Reader  Antenna ( MHz)  Strain Gauge  WISP

Equipment Setup cont’d

Assembly of Prototype Board  Strain Gauge Printed Circuit Board (SGPCB)

Assembly of Prototype Board cont’d

Wheatstone Bridge and Amplifier

WISP Software [ 1 byte | tag type] + [ 8 bytes | data] + [ 1 byte | WISP HW Version] + [ 2 bytes | HW Serial #] [11]11

Experimental Results Fig. 13 WISP with leads for V in, V out, and Ground

Experimental Results 1234

Limitations and Obstacles  Limited time  Limited knowledge of electronic components and code  Hardware limitations  Comparison of results virtual and experimental

Future Work

Cost Analysis Budget$ Impinj Speedway 1000 RFID Reader$ Antenna ( MHz)$35.00 Strain Gauge (SGD-13/1000-LY11)$ WISP Development Kit$0.00 Stainless Steel Lorenz Pectus Bar$0.00 Total$360.00

Gantt Chart

Questions?

References  [1]Medscape jpg.  [2](2012, Diseases & Conditions: Pectus Excavatum. 2012(2012/12/05). Available:  [3](2012, 2012/12/2). Adult Pectus Excavatum. Available:  [4](2009, 2012/12/02). Pectus Excavatum Exercise Program.  [5](2012, Pectus Excavatum. Thoracic Diseases & Disorders at Columbia University Medical Center (2012/12/2). Available: conditions/pectus-excavatum-symptoms/  [6]2012/12/02). Our Pediatric Surgeons. Available:  [7]K. R. J. Redlinger RE Jr, Nuss D, Kuhn MA, Obermeyer RJ, Goretsky MJ. (2011, One hundred patients with recurrent pectus excavatum repaired via the minimally invasive Nuss technique- -effective in most regardless of initial operative approach. Available:  [8]M. Roberti. (2012, What Is a Semi-passive RFID Tag? RFID Journal. Available:  [9](2010, WISP: Wireless Identification and Sensing Platform. Available:  [10]P. F. Federico Gasco, Jeff Braun, Joshua Smith, Patrick Stickler, Luciano DeOto. (2011, Wireless Strain Measurement for Structural Testing and Health Monitoring of Carbon Fiber Composites. Available:  [11]P. Powledge. (2009). Working with WISP Firmware. Available: