Transcript Disposable Mattress Cover with Wet Sheet Sensors

Disposable Mattress Cover
with Wet Sheet Sensors
ECE 4884 L05
Advisor: Dr. Art Koblasz
Team Members:
Youn Hur
Michael Wozniak
Pyungho Chung
Dongki Yoon
Project Overview


Improve upon previous group’s
design to build a disposable
mattress cover with wetness
detection function
Client
Hospitals, Nursing Homes,
and Patient Caring Facilities

Cost
$22.14 ($1.96 + $20.18)
Deviations from Previous Designs
Mattress Parts
Conductive Ink
or
32 gauge wire
Circuit Parts
9V DC
5V AC
Technical Objectives



Safe, sanitary, comfortable and
durable mattress cover
Detection function to alarm wetness
and breakage in conductive pattern
AC signal testing circuit
Technical Specification
Mattress Cover


Cost : Less than $2
Current


Drawn from detection circuit << 0.5 mA
Dimensions
Materials
Technical Specification
Detection Circuit


Cost : Approximately $20
Current source


Dimensions (Casing)


110V AC
25 cm x 20 cm x 15 cm (L x W x H)
Parts

Microcontroller, Opto-isolator, Rectifier,
Transformer, Resistors, Wires, Circuit board,
Connector, Casing, Wall plug-in
Overall Construction
Power Adaptor
Detection Circuit
Output of Circuit
(USB, Wireless)
Computer
Connector
Mattress Pad
Mattress Conductive Pattern



Two intertwined loops
to cover top surface
with 10~15 cm spacing
Each loop can be
checked for continuity
(breakage)
AC signal sent to one
loop can be read from
the other loop for
wetness detection
Connector & Power Adapter
Detection Circuit Schematic
Design Approach
Microcontroller




Low power consumption, low cost,
and self-sufficient
Arithmetic logic to detect its own AC
signal that runs through mattress
cover
Utilize A/D converter
Easy to manipulate
Design Approach
AC Signal Testing



DC changes PH level in an electrolytic
solution and leads to destruction of
neurons
Electricity can be detected by sense of
touch at 0.5 mA
(current range should be much less)
AC does not change PH and can be
healing stimulant
Testing & Demonstration

Safety test



Measure AC signal strength
Sit on wet cover
Durability test



Pull and tear to test mechanical
strength of bed sheet
Fold and crumple to check breakage of
conductive pattern
Run higher voltage through the circuit
Problems & Issues



Providing electrical isolation between the
circuit and the mattress
Keeping cost of materials low as more
parts being added
Contacting material suppliers to create
the prototype is time-consuming
Project Schedule
March
3/10
2weeks
3/24
Analog Circuit
Design
3/19
1week
Circuit Design w/
Microcontroller
end
3/21
3days
Microcontroller
coding
April
3/31
1week
Pattern Design/
Assembly
end
4/4
4/7
1week
Testing
end
4/11
end
3/28
Current Status

Building a prototype



Building analog circuit and adjusting
components
Waiting for conductive ink print on PET
Writing micro-controller code
Questions?