Skin Color Monitor Sarah Offutt, Rachel Mosher, Victoria Vasys BME 301 March 7, 2008

Client: John Webster, Ph.D Department of Biomedical Engineering Advisor: Brenda M. Ogle, Ph.D., M.S. Dept. of Biomedical Engineering

Overview  Problem Statement  Background Physiology of Hot Flashes Existing Devices  Design Components Housing Design Clear Plate Circuit  Future Work  Questions

Problem Statement The goal is to design a device to monitor skin color changes during hot flashes, which could be used to provide the objective measurement needed for therapeutic drug testing for menopausal women.

Physiology of Hot Flashes  Decreased estrogen levels confuse hypothalamus- body is “too hot” Due to menopause, medications  Heart pumps faster, blood vessels dilate, blood flow to periphery increases Skin flushes red  85% of women experience hot flashes during menopause Sweating, sleep loss, interruption of daily activities

Existing Devices  Temperature Sensors  Skin conductance measurements  Skin-color-change detectors  We aim to merge the two technologies in order to best detect hot flashes Longer lasting Easier use

Last Semester  Blue LED and Phototransistor  Would like to improve on Specular Reflection elimination Smaller Larger color differentiation

PDS Summary  Measurements taken every 10 seconds  6 x 6 x 1 cm  50 g  Battery life to last for overnight reading  Comfortable and discreet

Housing Design  Needs: Aesthetics Durability Space for circuitry Comfort  3 options Box Flat Box Dome

Housing Design Matrix CRITERIAWEIGHTBoxFlat BoxDome Aesthetics250.1 (2.5)0.4 (10)0.5 (12.5) Durability (9.25)0.33 (8.25)0.3 (7.5) Space for LEDs and Circuitry (8.25) Comfort150.2 (3)0.35 (5.25)0.45 (6.75) Machinability50.5 (2.5)0.4 (2)0.1 (0.5) Cost50.2 (1)0.4 (2) TOTAL

Clear Plate  Skin kept flat  Even pressure  Needs to be: Transparent Lightweight Safe  3 options NOA61 Acrylic Glass

Clear Plate Design Matrix CRITERIAWEIGHTNOA61AcrylicGlass Safety (24.5)0.3 (10.5) Weight250.3 (7.5)0.5 (12.5)0.2 (5) Cost150.1 (1.5)0.4 (6)0.5 (7.5) Refractive Index150.3 (4.5) 0.6 (9) Machinability100.2 (2)0.5 (5)0.3 (3) TOTAL

Circuit  3 options Original Design Parallel Branch Design Op-Amp Design  Want circuit that will detect the smallest amount of change  Will make biggest difference in quality of project

Circuit Design 1 and 2  Circuit 1—Original Few circuit parts Low cost Easy to construct Lowest voltage output  Circuit 2—Parallel Few circuit parts Low cost Easy to construct 0-5V output range

Circuit Design 3  Op-amp More circuit parts Increased cost Harder to construct Offset resistor Ranges -5 to 5V

Circuit Design Matrix CRITERIAWEIGHTOld Circuit Parallel Branch Circuit Op-Amp Circuit Differentiation500.1 (2.5)0.2 (5)0.7 (17.5) Ease200.4 (10) 0.2 (5) Size200.4 (10)0.4 (8)0.2 (4) Cost100.4 (4) 0.2 (2) TOTAL

Final Design  Blue LED  Phototransistor  Dome housing design  Acrylic Plate  Op-amp Circuit

Current Work  Specular reflection eliminated  Tested different colors of “skin”  Compared different colors of LEDs  Phototransistor compared with photocell  Housing will be made soon

Future Work  Design Circuit Finding skin color output range Setting offset Testing skin color values with exercise  Making Independent Print Circuit -5 to 5V source Recording device  Implement Housing Design

References  Carpenter, J. S., Azzouz, F., Monahan, P. O., Storniolo, A. M. & Ridner, S. H. (2005). Is sternal skin conductance monitoring a valid measure of hot flash intensity or distress? Menopause, 12(5), Carpenter, J. SAzzouz, FMonahan, P. OStorniolo, A. M Ridner, S. H  Raskin, B. (1987). Hot Flashes. New York: St. Martin’s Press.  Singh, M. & Simpkins, J. W. (Eds.). (2005). The future of hormone therapy : what basic science and clinical studies teach us. New York: New York Academy of Science.  Wearable hot flash monitor (WHFM). Metis Design Corporation. Retrieved February 17, 2008 from  Webster, J. G., Bahr, D. E., Shults, M. C., Grady, D. G. & Macer, J. (2006). A miniature sternal skin-attached hot flash recorder. International Federation for Medical and Biological Engineering, 14,

Questions