1. Disposable Mattress Cover with Conductive Threads to Detect Wetness using Resistance Comparison ECE 4884 L03 Advisor: Dr. Koblasz Team Members: Ankit Hemani Jacob Huang Yuval Rooz Heonwoo Song Sarju Vasavada

2. Motivation 2 million cases of nosocomial (hospital- acquired) infections annually (CDC) Wet bedsheets increase risk of infection

3. Design Objectives Use biodegradable plastic and paper Stitching conductive threads on the paper to detect wetness Design a detection unit Detect a break in the circuit Detect wetness Isolate electrical circuitry from patient

4. Cost Analysis ItemPrice Paper$0.65 Thread$0.80 Biodegradable Polyethylene$0.20 Mattress Cover per unit cost$1.85 I.C.s$4.17 Circuit board$4.99 Encasing Box$6.99 RS-232, Power jacks$10.00 AC/DC Adapter$13.87 Fuse, Fuse Holder$3.40 Resistors, Capacitors, LED, Wires< $1.00 Detection Unit cost$43.42

5. Layout Of Mattress Cover On Hospital Bed Source: http://www.ponsishoes.com/products.asp

6. Mattress Cover Construction Plastic attached to paper using adhesive Plastic on the bottom side, paper on the top

7. Conductive Thread Stitching Conductive threads laid out on paper in two loops, of 40 ft each Regular threads used to stitch conductive threads on paper

8. Power Supply 12V AC/DC Adapter + Transformer 12V AC/DC Adapter + Transformer Fuse 9V Regulator Transformer and fuse used to protect against voltage spikes

9. Detection Unit Reading from mattress cover Reading from mattress cover Continuity detection Continuity detection Wetness detection Wetness detection Opto-isolator Output

10. Detection Unit Schematic

11. Communication between Pad and Detection Unit Plastic clip Four metal pads contact the conductive loop on sheet Wires soldered to pads connect the clip to the detection unit

12. Modifications to Proposed Items ProposedDesignedReason Silver ThreadStainless steelMore conductive BatteryWall OutletCumbersome Two OutputsOne OutputNo need for two Phone-jackPlastic clipFaster attachment -Opto-isolatorSafety

13. Current Status Stitched a paper bedsheet (has discontinuities) Tested unit with a cotton bedsheet Stitched a (non-working) paper bedsheet Built detection unit Designed a prototype connector

14. Steps for Marketable Product Include clip in connector Casing for detection unit Investigate cheaper conductive threads Implement with full-size hospital bedsheet nor biodegradable polyethylene Optimize resistances in detection unit

15. If time allows, video of a project demonstration Video

16. Any Questions?