Biomedical Wireless Sensors to Biomedical Wireless Sensors to Control a Spinal Slope AngleControl a Spinal Slope Angle

Alina TurokAlina Turok1

BackgroundHealth and Rehabilitation Research Institute at North Shore campus holds experiments in order to learn to control bending and prevent harm.

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An average person bends a lot of times during the day: exercising, picking up fallen objects, working.

Background

For every person the point when the bending angle becomes harmful is different.

• Industry made Shimmer Sensors

Existing Sensors

• Project 2013 – Wired Sensors

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Project Purpose

The aim of this project is to advance the

concept of wireless sensors:

convenient to use

stable data stream

accurate final output

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Project Purpose

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First Approach

soldering of the USB dongle + JTAG connector – ready to be programmed

second set of wired sensors to be developed

To embed radio modules into the existing devices and modernize the code in order to get wireless modules to talk to each other.

part of the code is missing – the concept is impossible to fulfill

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Standard Bluetooth,

IEEE 802.15.1

WiFi,

IEEE 802.11(a,b,g)

ZigBee (XBee-PRO),

IEEE 802.15.4

Transmission Range 10 meters 50-100 meters 60-3200 metersSignal Rate 723 kbps 11; 54 Mbps 250 kbpsNumber of Channels 79 14 (2,4 GHz) 16Channel Bandwidth 3 MHz 22 MHz 2 MHzOperating Frequency 2,4 GHz 2,4 and 5,8 GHz 868/915 MHz

2,4 GHzPower Consumption medium high very lowSleep Power 8 uW 10 uW 4 uWNumber of Nodes on Network 8 32 65000+

Network Topology Options star point to hub peer-to-peer, star, mesh

Latency up to 10 s up to 3 s up to 30 ms

Security 64, 128 bit encryption authentication Service Set ID (SSID), WEP

128 AES, application layer security

Stability low high HighComplexity of Implementation a bit complex complex very simple

Cost low high High

Wireless technologies’ comparison

Excellent

Poor

Satisfactory

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XBee-PRO® ZB RF Module

Mesh network

Self-healing

SMT with PCB antenna

Up to 3200 m range

2.2 x 3.4 cm

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Small, thin

Measurement mode 40uA

Standby mode

0.1uA

Digital data output

SPI

ADXL345

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ZegBee Network Design

ZigBee network includes three items:

Coordinator (only one per network)

Routers 

End Devices

All nodes can transmit and receive, but to be on one network each should have:

Unique PAN ID

Assigned channel

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Final Product Design

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The set of wireless modules is comprised of:

Two Sensors: XBee module + microcontroller + accelerometer + battery

XBee USB Dongle: XBee module + UART + USB connector

Block Diagrams

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XBeeModule(Router)

 

 

  MCADXL345

IC +

Crystall

JTAG

SPISPI UARTUART

Battery

   UART USBXBee

Module(Coordinator)

:USB dongle

Sensors:

Modules Configuration

XBee® ZigBee SMT RF Module Development Kit

Multi-platform XCTU application Available for download from

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Programmable Modules

  XBeeModule

 ADXL345

SPI

New block diagram with programmable XBee

XBee-PRO® ZB Programmable Development Kit

XBPP24CZ7PIS-004

XBee-PRO

Programmable Professional

NO SPI hardware coming out of the module

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Prototype Development

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Data from ADXL345 in a console window of ARDUINO

Final Testing

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X, Y, Z coordinates highlighted

Data Packet From ADXL345

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To display an output in decimal numeration to an application responsible for calculations (LabView).

Develop a final product on the basis of the prototype.

Another variation of networks with greater amount of end devices and routers to work in 3D dimension.

Next Steps

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