SAPHED08: Sensing Prototype

Sensing Prototype
SAPHE
Issue : 1.0
Document Reference: D08

Author: Nigel BarnesDate: 5 Jan 2009

Table of contents

Introduction

1Sensing system architecture

2Component Specification

2.1Environmental Sensors

2.1.1Sensors

2.1.2Communications

2.2SAPHE Home hub (aka set-top box)

2.2.1Hardware

2.2.2Software

2.2.3Communications

2.3Home Gateway

2.4Interaction devices

2.5Third party point-of-care devices

2.6Body worn sensors

2.6.1Sensors

2.6.2Communications

2.7SAPHE Mobile hub

2.7.1Hardware

2.7.2Software

2.7.3Communications

2.7.4Mobile phone connectivity

2.8SAPHE Network platform

Appendix 1: SAPHE Common Data Protocol

Document history

Introduction

An end-to-end SAPHE system prototype was demonstrated at ImperialCollege on 10th December 2007 meeting Milestone M4, System Prototype. This document provides an overview of the system produced and serves as a record of the associatedDeliverable D08, SAPHE Sensing Prototype.

Section 2 of this report follows similar structure to section 5 of D07, SAPHE System Technical Specification. This is to allow changes from the original specification to be highlighted.

This document serves only to give an overview of the SAPHE Sensing prototype implemented. It is not intended to give deep technical insight; as such it only highlights key changes from D07 without revised detailed technical description.

Details of the Network Platform and associated applications beyond the recording of sensed data into the Network Platform database are beyond the scope of the Sensing Prototype and hence are omitted from this document.

1Sensing system architecture

The top level architecture of the sensing prototype is shown in Figure 1 below.

Figure 1: SAPHE Sensing PrototypeTop Level Architecture.

The Sensing Prototype has demonstrated the capture of the following sensor data:

  • Non-invasive activity monitoring from Passive Infra-Red (PIR) sensors
  • Weight monitoring from personal weight scales
  • Activity monitoring from a worn e-AR sensor
  • Heart rate and Sp02 monitoring from a worn e-AR sensor

A common data protocol has been implemented for communications from SAPHE developed sensors over the following communication links:

  • ZigBee from PIR sensors to Set-Top Box
  • Philips Low Power Radio from e-AR sensor to Mobile Hub
  • Bluetooth from Mobile Hub to Set-Top Box

The SAPHE common data protocol is described in Appendix 1.

2Component Specification

This section follows the same structure as Section 5 of the SAPHE System Technical Specification (D07).

2.1Environmental Sensors

2.1.1Sensors

Blob

[Change from D07]

Blob Sensors are no longer part of the initial trial plans. It is hoped prototype devices will be available for deployment towards the trial end. Communication will be via ZigBee communications as defined below.

PIR

[Change from D07]

Visonic ‘Discovery W’ or ‘K-980W’ PIRs have now been selected. The two PIRs are physically identical however the K-980W’s provide pet immunity (up to 36Kg) and have a range of 12m x 12m whereas the range of the Discovery W is 15m x 15m. Further details can be found at

These devices are able to operate in a continuous (Test) mode of operation without modification and are powered by a 9v PP3 battery.

The ZigBee module will be housed within the existing PIR casing and will be powered by a separate 3.6V 2/3AA Lithium battery (1.7Ah) also housed internally. An internal pcb mounted ceramic antenna will be utilised.

Magnetic Contact

[Change from D07]

Standard low cost magnetic contacts will be utilised, see

The ‘active’ component will be suitably housed together with the same ZigBee module as for the PIR.

Temperature

[Change from D07]

The ZigBee modules utilised for PIRs and Magnetic contacts provide on board temperature sensing. It will therefore not be necessary to provide dedicated temperature sensors.

Bed Occupancy

[Updated from D07]

Following the development by Tactex Controls of Quality of Sleep analysis algorithms the actigraphy version of their bed sensors are to be used. The quality of sleep algorithms will provide the following sleep measurements:

  • Sleep efficiency
  • Sleep Latency
  • Total sleep time
  • Number of awakenings
  • Wake after sleep-onset, and
  • Bed exits

Algorithms will operate on sensor data collated on the Network Platform.

Communication of the sensor output will be via Bluetooth (utilising a Tactex Bluetooth interface unit) to the STB.

2.1.2Communications

ZigBee

[Change from D07]

ZigBee based communication is enabled from environmental sensors using Jennic ZigBee modules.

Sensors will be battery powered as described in 2.1.1.

2.2SAPHE Home hub (aka set-top box)

2.2.1Hardware

[Confirmation of detail from D07]

The STB is built upon a mini-ITX PC platform utilising an VIA EPIA CN10000EG motherboard providing a 1GHz processor with fanless operation.

Ancillary components:

  • 512MB RAM
  • KingstonValue Ram 512MB DDR2 533MHz PC4200 DIMM
  • KVR533D2N4/512
  • Secure Digital (SD) card for OS and applications
  • SanDisk 2GB Extreme III
  • WLAN (IEEE 802.11G)
  • Belkin Wireless PCI card
  • F5D7001UK
  • Bluetooth
  • Belkin F8T012 Bluetooth USB Class 1
  • Case
  • Silverstone ML-02-MXR with MCE remote & display
  • SST-ML02B-MXR

A ZigBee dongle will be externally mounted and will connect to the ITX board via a USB connection. The ZigBee dongle will utilise an external antenna.

2.2.2Software

Operating System

[Updated from D07]

Ubuntu Linux 8.1.

Security and Messaging

[Updated from D07]

  • IPSEC based VPN connectivity to the network platform.
  • JMS messaging utilising OpenMQ 4.1.
Applications

[As per D07]

2.2.3Communications

In home

[As per D07]

The SAPHE Home hub simultaneously supportsZigBee, Bluetooth and WLAN (IEEE 802.11g) communications within the home.

The SAPHE home hub acts as the coordinator of the ZigBee network for the environmental sensors.

Bluetooth Class 1 is provided to communicate with the SAPHE mobile hub and off-the-shelf medical devices utilised within the trial.

WLAN (IEEE 802.11 g) will be used to communicate with the Home Gateway.

Network platform

[Updated from D07]

Communications between the SAPHE home hub and the SAPHE network platform will be via the Home Gateway (BT home Hub) and will use a VPN connection.

Java Message Service (JMS) is used for data transfer between the STB and the SAPHE network platform. The chosen implementation is OpenMQ 4.1.

A dedicated hardware device has been implemented on the Network Platform to provide firewall and VPN capabilities. The device a Cisco ASA 5510 Security Plus Appliance(ASA5510-SEC-BUN-K9). In addition to IPSEC VPN the device also provides OpenSSL based VPN capability if required.

Figure 2: SAPHE End-to-End Prototype Implementation.

Note: OpenMQ 4.1 is utilised in place of ActiveMQ 5.x as shown in Figure 2.

2.3Home Gateway

[As per D07]

BT Homehub will be specified by default.

An automatic configuration script runs on the SAPHE Home hub.

Where broadband already exists it will be determined if the user’s existing device can be used.

2.4Interaction devices

[Not yet implemented]

2.5Third party point-of-care devices

[Confirmation and update from D07]

  • Weight – Motiva Bluetooth Scales, Model M3813B, Manufactured by T-Systems
    These scales are the same as used in the Philips Motiva trials and send weight data to the set top box using a Bluetooth connection using a proprietary XML protocol. Weights can be taken in either lb or kg, there is no option for stones.
    The interface presented to the user is via a LCD display and interaction is assisted by voice instructions so it is clear to the service user when to stand on and off the scales.
    Measurement data is encrypted using existing Bluetooth encryption methods.
  • Blood pressure – A&D UA-767PBT, upper arm cuff device.
    This device provides simple single button operation with a clear display.
    Communication is via Bluetooth to the STB utilising a proprietary protocol.

2.6Body worn sensors

2.6.1Sensors

e-AR

[As per D07]

ECG

[Not part of trial]

ECG – event recorder

[Not yet integrated]

The Cardionetics C.Net5000 ECG recorder will be utilised. This will communicate with the mobile hub via the Philips Low Power Radio housed within a dongle attached to the recorder’s serial port.

2.6.2Communications

Body worn sensors communicate wirelessly to the SAPHE mobile hub via the Philips Low Power Radio.

2.7SAPHE Mobile hub

2.7.1Hardware

The mobile hub is a custom designed and built hardware platform, providing communications and power management.

  • MSP430: This 16-bit Texas Instruments microcontroller is specifically designed for low power applications and forms the heart of the mobile hub. The main tasks of the MSP430 are to manage connection between the other components and to oversee the power management of the system.
  • MMC Card: When the mobile hub is out of range of the home hub, or the power management algorithms have determined that it is not necessary to keep the Bluetooth link powered, a MMC card is used to buffer the received sensor readings.
  • LegoBrick Radio: The LBR provides the connectivity to the other body sensors specified in this document and is further described in section 2.7.3.
  • Real Time Clock:The RTC allows the mobile hub to keep track of the incoming messages and ensure that they are delivered in the correct order to the backend system. The time on the Mobile hub is internal and is converted to “real-world” time on the home hub.
  • Bluetooth Module: A separate Bluetooth module is used to allow the mobile hub to synchronise with the home hub. This is connected and controlled by the MSP430 using a software RS-232 implementation.
  • Charging Circuit: The mobile hub is operated by a LiIon battery and a charging circuit is included in the design. The mobile hub is connected to power using a standardised mini-USB connector.

2.7.2Software

The mobile hub software is as follows:

  • MSP430 software controls the whole operation of the mobile hub. The software is all custom written and is responsible for communication with the various peripheral devices described above as well as ensuring optimal power consumption.The components can be seen in the following system overview:

2.7.3Communications

Philips Low Power Radio

[As per D07]

Communication with body worn sensors

Bluetooth

[As per D07]

Communication with SAPHE STB.

2.7.4Mobile phone connectivity

[Not yet implemented, out of scope for trial]

The SAPHE mobile hub will have the ability to communicate with a service user’s mobile phone via Bluetooth. This will facilitate the following functionality:

  • Use of the mobile phone as a GUI.
  • Remote connectivity to the SAPHE system.
  • Tracking/location of the service user.

2.8SAPHE Network platform

[As per D07]

An OpenMQ 4.1 JMS broker has been deployed on the Network Platform to manage communications with the STB and act as a central point for reception of all raw sensor data.

MySQL Server 5 has been deployed to provide all database functions. The database contains all raw sensor data,system configuration data, and processed data information.

JMS communication over IPsec (Linux clients) and L2TP/IPsec (Windows clients) have been demonstrated between partner (ImperialCollege, Dundee university and Philips) sites and the BT Network Platform. The master database (hosted by BT) is remotely replicated (as slave databases) by both ImperialCollege and Philips.

Further detail is out of scope for this document.

Appendix 1: SAPHE Common Data Protocol

These slides have been taken from ‘SAPHE Common Protocol v 0.91.ppt’ which may be found in the WPB7 download folder on the SAPHE project website. Future revisions of the protocol will be posted in to this folder.

The protocol refers to the formatting of data contained within the payload of the communications protocols in use, e.g. ZigBee, Bluetooth, Low Power Radio etc.

Document history

Issue / Date / Prime author(s) / Comments
Draft 0.1 / 11/01/2008 / Nigel Barnes / Skeletal draft based on D07 Section 5.
Draft 0.2 / 16/01/2008 / Nigel Barnes / Revision to section 2.8 (Network Platform) and updated Figure 2 (End-to-End Prototype Implementation) by Tom Mizutani.
Incorporation of SAPHE Common Protocol slides into Appendix 1.
Draft 0.3 / 24/01/20008 / Nigel Barnes / Minor edits and referencing to D07.
Issue 1.0 / 05/01/2009 / Nigel Barnes / Mobile hub revision to section 2.7 by Rob Blake, updates to Network Platform implementation in 2.2 and 2.8 including shift from ActiveMQ to Open MQ and removed reference to MS SQL Server which is no longer used.

End Of Document

Author: Nigel BarnesIssue: 1.01