Transcript Detection Unit

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
Motivation
• 2 million cases of nosocomial (hospitalacquired) infections annually (CDC)
• Wet bedsheets increase risk of infection
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
Cost Analysis
Item
Price
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
Layout Of Mattress Cover On
Hospital Bed
Source: http://www.ponsishoes.com/products.asp
Mattress Cover Construction
• Plastic attached to paper using
adhesive
• Plastic on the bottom side, paper on
the top
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
Power Supply
• Transformer and fuse used to protect
against voltage spikes
12V AC/DC
Adapter
+ Transformer
Fuse
9V
Regulator
Detection Unit
Continuity
detection
Reading from
mattress cover
Wetness
detection
Opto-isolator
Output
Detection Unit Schematic
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
Modifications to Proposed Items
Proposed
Designed
Reason
Silver Thread
Stainless steel
More conductive
Battery
Wall Outlet
Cumbersome
Two Outputs
One Output
No need for two
Phone-jack
Plastic clip
Faster attachment
Opto-isolator
Safety
-
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
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
Video
• If time allows, video of a project demonstration
Any Questions?