Smart Mattress

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Smart Mattress
Bryan Kuo, Priyen Patel, Dev Shah, Xitij Shah,
Tim Stamm Georgia Institute of Technology October
23, 2008
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Project Overview

• Goals
• Prevent bedsores acquired on hospital/nursing
  home beds
• Wetness Detection
• Inactivity Detection
• Prevent incorrect medication administration
• Patient Identification System
• Patient Barcode Display
• Clients
• Hospitals
• Nursing Homes
• Cost 1,600

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Design Objectives

• Identify patients using RFID
• Display patient information and barcode on a PC
  monitor
• Detect moisture and patient inactivity that could
  cause bed sores
• Alert staff if patient is in danger of developing
  bed sores

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Overall System - Current
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RFID System

• RFID antenna located at foot of bed
• Dynasys RFID tags on patients ankles
• Patient tag compared to patient ID database
• Patient name and barcode displayed on PC

RFID Tag and Antenna Reader
HP Slimline PC
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RFID System

• OBID i-scan HF RFID Reader
• OBID i-scan HF Pad Antenna
• RFID Operating Frequency 13.56 MHz
• RFID Antenna Range 7 in.
• RFID Transmitting Power 1W 2 dB
• Note This range may not meet specification
  requirements

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Inactivity Monitoring System
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Inactivity Monitoring System
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Wetness Detection

• Conductive thread connected to wetness detection
  circuit
• 1st comparator monitors moisture
• 2nd comparator detects breaks in conductive tape

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Wetness Detection System
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From Prototype to Final Design
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PIC Microcontroller

• Low power operation using 3V coin cell battery
  and PIC18F2321
• Programmed in C via 6-pin header through PICkit2
  using MPLAB IDE
• RS232 communication to PC using onboard UART
• Pushbutton and LED for debugging

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PIC for Final System Implementation

• Inactivity monitoring
• Sample force sensing resistors using onboard ADC
• Wetness detection
• Sample output of comparators using digital input
• Phidgets cost 110 versus 30 for PIC system

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Current Status

• Wetness detection circuit
• Implemented on breadboard
• 2 comparators and 3V battery power supply
• Output tested with multimeter
• Inactivity monitoring system
• 4 Trossen Robotics force sensing resistor strips
  with Phidget voltage dividers
• Sampled with Phidget 8/8/8 Interface Kit and
  center of mass calculated using Visual C
• RFID System
• Tested preliminary reader and tag functionality
• Have demonstrated software control in Visual C,
  but still needs further refinement

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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

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Project Schedule
Acquire Parts 9/19/08
Start Testing Wetness Detection 10/19/08
Start Testing Inactivity Monitor 10/19/08
Develop RFID System 11/10/08
Develop Graphical Display 11/15/08
Develop PCB 11/20/08
Implement the Full System 11/30/08
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QUESTIONS?