Wearable gas sensorsgTanja Radu, Cormac Fay, King Tong Lau, and Dermot Diamond

ABSTRACT. Wearable sensing applications have attracted much attention in recent years. The aim of the FP6 funded Proetex project is improving safety and efficiency of emergency personnel by developing integrated wearable sensor systems. This paper describes recent developments in the integration of sensing platforms into wearables for the continuous monitoring of environmentally harmful gases surrounding emergency personnel. Low-power miniature CO and CO2sensors have been successfully integrated in a jacket collar and boot worn by emergency personnel. These sensors need to provide information about the level of gas in the surrounding environment without obstructing the activities of the wearer. This has been achieved by integrating special pockets on the jacket and boot of fire-fighters. Each sensor is attached to a sensing module for signal accommodation and data transfer. The sensor performance has been evaluated by simulation of real-life situations. These wearable gas sensors will dramatically improve personnel awareness of potential hazard and can function as a personal warning system. In this way, fire-fighter’s jacket and boot not only protect the wearer, but have a second function of providing valuable information on external hazards.

Outer Garment Wearable:External chemicals sensingPosture and activityVisibility enhancementPower generation and storageLow power local communications

Inner Garment Wearable:Life signs monitoringTemperature, internal Biochemicals sensingPosture and activityPower generation and storageLow power local communications

Long Range C i ti

Local communicating network. Each wearables/portable acts as a node.The PROeTEX

Concept

CO

Base station

- Collects info onexternal hazards

- WARNING if indanger Remote base station

Long range communication

Disaster Management Control

DCU’s role in PROeTEX

CO2

CO

Advanced E-Textile systems can bring togethersensors, connections, transmission systems, powermanagement. The emergency disaster personnel smartgarments will progressively enhance and integrate such textilesystems to enable the following functions:

• Continuous monitoring of life signs (biopotentials, breathingmovement, cardiac sounds);• Continuous monitoring biosensors (sweat, dehydration, electrolytes, stress indicators, O2, CO);• Pose and activity monitoring;

Portable Communications Units:6 axis INS; GPS;External temperatureAdditional sensorsOn board battery storageLow power local communicationLong range communicationsData input ; Display and audio, alarms

Ambient Environment:CommunicationsPlanningCoordination MonitoringPredictionSituation awareness

Local Communication

Communication

Civilian Monitoring Jerkin: (or chest band)Life signs monitoringTemperature, internal Biochemicals sensingPosture and activityPower generation and storageLow power local communications

Co cept

Base station

• Warnings• Decisions• Information• Strategy

CO

CO2

CO2

y g• Low power local wireless communications, includingintegrated textile antennae;• Internal temperature monitoring using textile sensors;• External chemical detection, including toxic gases andvapors;• Power generation - photovoltaic and thermoelectric andenergy storage;• Longer term e-textile technologies including furthersensors, light emission and logic on fibre.

CO2 sensing

• Potentiomentric sensor• Sensor integrated into a boot pocket• Wireless transmission using Zigbee

CO

CO sensing

• Amperometric sensor• Sensor integrated into a jacket collar

Principle of a PotentiometricSensor for Gases The signalis measured as the potentialdifference (voltage) betweenthe working electrode and thereference electrode. Theworking electrode's potentialdepends on the concentrationof the CO2 in the gas phase

Principle of a Amperometric Sensor for Gases Carbon monoxide is oxidized atone electrode to carbon dioxide whilst oxygen is consumed at the other electrode. Inan electrochemical cell selective to CO, the current that flows between the twoelectrodes, is proportional to the amount of CO presentWorking electrode (anode): 2CO + 2H2O --> 2CO2 + 4e- + 4H+

Counter electrode (cathode) 4H+ + O2 + 4e- --> 2H2OOverall react. 2CO + O2 --> 2CO2

V

working electrode

ionic conductor(solid electrolyte)

referenceelectrode

CO sensor

CO2injections

Wireless sensing module Firefighter’s boot Testing chamber

Base station (PC)

CO Sensors response to three single CO injections, each resulting in CO concentration of 405 ppm

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Raw data and calibration curves from two CO sensor calibrations in concentration range: 0 ppm, 90 ppm, 225 ppm, and 405 ppm.

FUTURE ACTIONS- Full integration of CO/CO2 sensors into the garment- Wireless transmission: communication of on-body base station and the remote station

Wirelessly transmitted signal from CO2 sensor calibration (range atmospheric to42800 ppm CO2). Sensor was enclosed in an airtight chamber and CO2 was injected.

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32 CO2 concentrations

1. atmospheric (initial base line) 2. 9750 ppm, 3. 19500 ppm, 4. 29300 ppm,5. 42800 ppm

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UNIVERSITY COLLEGE DUBLIN DUBLIN CITY UNIVERSITY TYNDALL NATIONAL INSTITUTE

This work is supported by Science Foundation Ireland under grant 07/CE/I1147

AKNOWLEDGEMENT: European Union project FP6-2004-IST-4-026987, University of Pisa (Italy), Zarlink Semiconductor (UK), and Diadora/Invicta Group (Italy)

- Evaluation of prototypes in laboratory conditions- Evaluation of prototypes in-field conditions

CONTACT: Tanja.Radu@dcu.ie