Smart Mattress

Bryan Kuo, Priyen Patel, Dev Shah, Xitij Shah, Tim StammGeorgia Institute of Technology

December 5, 2008

Project Overview

Goals: Prevent bedsores acquired on hospital/nursing home beds

Wetness DetectionInactivity Detection

Prevent incorrect medication administrationPatient Identification SystemPatient Barcode Display

Clients: Hospitals Nursing Homes

Cost: $1,055

Design Objectives

Identify patients using RFIDDisplay patient information and barcode

on a PC monitorDetect moisture and patient inactivity that

could cause bed soresAlert staff if patient is in danger of

developing bed sores

Overall System - Current

Overall System - Current

Previous RFID System

Passive RFID System OBID i-scan HF RFID Reader OBID i-scan HF Pad AntennaRFID Operating Frequency: 13.56 MHzRFID Antenna Range: 7 in. RFID Transmitting Power: 1W ± 2 dB

* Note: This range did not meet our specifications

Current RFID System

Active RFID SystemWavetrend RX201 Active RFID ReaderWavetrend AN100 Active Whip AntennaRFID Operating Frequency: 433 MhzRFID Antenna Range: 35 ftRFID Wavelength: 2.3 ftTag Battery Life: 5 years

RFID System

RFID antenna located at foot of bedWavetrend Active RFID tagsPatient tag compared to patient ID databasePatient name and barcode displayed on PC

RFID Tag Reader and Antenna HP Slimline PC

RFID Detection Range

Inactivity Monitoring System

Inactivity Monitoring System

Wetness Detection

2 conductive loops of tape connected to wetness detection circuit

1st comparator input monitors moisture

2nd comparator detects breaks in the conductive loop

Wetness Detection System

Phidget 8/8/8 Interface Kit

Interface between inactivity monitoring and wetness detection systems with HP Slimline PC

4 analog inputs for FSR strips 1 analog input for sampling wetness

detection circuit output

Current Status

Wetness detection system 2 conductive loops, comparator, and 2 9V batteries Successfully implemented and tested on breadboard

Inactivity monitoring system 4 Trossen Robotics force sensing resistor strips Controlled through Phidget 8/8/8 interface kit Successfully implemented and tested

RFID System Wavetrend Active RFID Reader/Antenna Successfully implemented and tested

Design Specifications

Same1.5 to 150 psiPressure Sensor Range

Same0 to 1000 lbsForce Sensitivity Range

  Trossen Robotics 24” FSR

Same16 msSwitching Loop-time

 < 5mACurrent Consumption

2 9V batteries 3.3  VPower Supply

Phidget 8/8/8 Interface KitPIC18 LF2321Microprocessor

  Multiplexer

 Max. 0.5 ARFID Current Draw

35 ft.1 ft (12 in.)Max RFID Reading Distance

N/A1W ± 2 dBRFID Transmitting Power

433 MHz13.56 MHzRFID Operating Frequency

  RFID Reader

ActualProposedTechnical Specifications

Competing Products

Total Care SpO2RT Hospital Bed Secure II Med/Surg Hospital Bed

$28,500 $10,000

Cost

$250$2501HP Slimline PC

$1,055 Total Equipment Cost

$50 $50 1PC Monitor

$30$30 1Bed Sheet

$150 $150 1Mattress Foam

$50 $50 75ftConductive Tape

$307 $307 1RFID Tag and Reader

$15 $7.50 29V Battery

$15 $15 1Wires/Cables

$80 $80 1Phidget 8/8/8

$108 $27 4FSR Robotics Sensor Kit

Total CostUnit CostQuantityPart

Selling Points

Lower cost Costs $1,055 Competitor products cost at least $10,000

Portable More versatile

Combines wetness and inactivity detection Utilizes RFID to prevent improper

medication administration Appealing Graphical User Display

Future Considerations

Use a smaller, cheaper microcontroller such as a PIC

Implement systems on a PCB Find smaller wrist/ankle band active

RFID tags

PIC Microcontroller

Used for integrating wetness detection, inactivity monitoring, and patient identification systems into a low-cost power-efficient package

Low power operation using 3V coin cell battery

Programmed in C via 6-pin header through PICkit2

RS232 communication to PC using onboard UART

Pushbutton and LED for debugging

PIC for Inexpensive System Integration

RFID Implement either using RS232 with current

reader or SPI enabled readerInactivity monitoring

Sample force sensing resistors using onboard ADC

Wetness detection Sample output of comparators using digital

inputLCD for display of system status

Demonstration Plan

Inactivity Detection Group member lays for extended period of time. LCD monitor displays inactivity alarm

Patient Identification RFID tag located within antenna range LCD monitor displays patient name LCD monitor displays patient medication barcode

Wetness Detection Salt water poured on bed LCD monitor displays wetness alarm