| ß Version - June 17, 2006 |
WEARABLE HEALTH CARE SYSTEM WEALTHY OBJECTIVES
3. Interface ß Version
Graphics and photos display the latest developments of WEALTHY.
back to top
3.1. Elasticity of Garment
As it can be seen from Figure 1 and 2, the garment is elastic enough to fit the body shape, the conductive elements are all integrated in the
textile to allow a perfect comfort during monitoring of signals.


Figure 1 shows the prototype model A, with electrodes and breathing sensors position, while Figure 2 shows the position of the movement sensors.
back to top
3.2. Respiration Measurements
An alternative strategy to measure respiratory activity is the use of the impedance pneumography. In this case four electrodes are placed on
thoracic position, as shown in Figure 3 (prototype B).

back to top
3.2.1. The Impedance Pneumography
The two external ones are used to inject a high frequency current (50 kHz) and the other ones allow capturing the voltage variation caused by thoracic
impedance change. The output signal is modulated by changes in the body impedance accompanying the respiratory cycle. The change in impedance corresponding
to each respiratory cycle is of the order of 1-4 % of the base impedance. The relationship between impedance change ?Z and volume of air moved (?V)
is approximately linear under most circumstances. Since the impedance changes are related to the volume of air moved, the method can be calibrated.
back to top
3.3. Measurements of Core and Skin Temperature
Two non-textile microelectronic sensors (Figure 4) are used to gather core and skin temperature of the patient. The key specifications of these integrated
circuits are temperature and accelerometer.

back to top
3.3.1. Temperature
- Accuracy: ±0.50°C (max)
- Linearity ±0.5°C(max)
- Resolution 0.0625°C
Several preliminary tests were performed relative to the choice of the location of the sensors for the skin temperature and the core temperature (location,
insulation, ergonomic, robustness of measurements, etc.). These tests will be completed by the measurement on the WEALTHY prototype.
back to top
3.4. Integration of sensors, electrodes and electrical wires
The potentiality of using textile facilities is linked to the implementation of functionalized fibers and yarns suitable to be used in the most sophisticated
weaving machineries; the fineness, the composition, the mechano-elastic properties of yarns play a key role in this process. The final characteristics of the
integrated textile structure are modulated by a series of factors, starting from the material, the combination of yarns, the textile process used, till to the
final finishing step. An efficient, wearable, comfortable sensing system is the result of a balance among performance, number, position of the active elements,
and lightness, comfort and conformability of the final cloth.
back to top
3.5. Accelerometer
On the low abdomen (left side) is placed a 2D accelerometer in order to monitor body position (stand, supine, etc.).
This accelerometer can measure both dynamic (e.g. vibration) and static acceleration (e.g. gravity). The measurement range is ±2g.
The outputs are digital signals whose duty cycles (ratio of pulse width to period) are proportional to the acceleration in each of the 2 sensitive axes.
back to top
3.6. Communication System
This chart illustrates the data flow.
back to top
3.6.1. Mobile data media

A small portable electronic device includes all the electronics for the conditioning and acquisition of the sensors signals. Local pre-processing capabilities
allow to extract some key parameters and so to reduce the amount of data to transmit. Data is transmitted in quasi real-time to the remote medical center using
a GPRS link over the standard GSM infrastructure, allowing usage of the garment almost everywhere. The latest version of this Portable Patient Unit (shown on
the right of the image) has a targeted weight of less than 250g, a size of 110mm x 70mm x 25mm and can so fit in a pocket of the garment. User interface has
been kept as simple as possible and consists of some visual indicators, a button and a buzzer
.
back to top
3.7. Monitoring System
The WEALTHY Central Monitoring System is a software module interpreting physical sensor data received from the Portable Patient Unit (PPU) and representing
them in simple, graphical forms.
The Central Monitoring System performs the following tasks:
- Coordinates and controls the data flow between the different actors.
- Collects and stores the data transmitted by the sensors integrated in the WEALTHY garment through the PPU.
- Continuously monitors vital health parameters of the patients.
- Generates alerts to inform doctors for critical health situations.
- Gives access to the central database to doctors and other health professionals.
- Presents to the qualified users the health situation of patients using different user-friendly interfaces.

back to top
|
 |
 |
© 2002 Wealthy - All Rights Reserved
The content of this page is the sole responsibility of the Consortium and in no way represents the views
of the European Commission or its services. Email the Official Contact Person of the project.
Last Updated June 17, 2006
|
|