Page 137 - Organic Electronics in Sensors and Biotechnology

114 Cha pte r T h ree

–16.0n
Cough
–14.0n
I d (A) –12.0n

–10.0n
Hiccup
–8.0n
0 10 20 30 40 50
Time (s)
FIGURE 3.26 Sensor output for cough and hiccup.

FIGURE 3.27 Experimental setup for detection of falls and gait analysis.

As can be seen the sensor response is reproducible and rather fast
(hundreds of milliseconds).
This technology can be helpful also for detection of falls or for
gait analysis through the detection of pressure exerted on shoes. In
particular we performed experiments inserting sensors under the
insole of a shoe to detect the pressure exerted by the foot, as shown
in Fig. 3.27.
In the experiment shown in Fig. 3.28, two sensors were positioned
under the heel and under the sole. As can be seen, it is possible to
clearly distinguish when the subject is on tiptoes or on heels or is
normally standing.
The employment of OFETs could enable building arrays and
matrices able to give a full spatial resolution to the measurement.
This feature is particularly useful for application as the gait analysis
or the detection of posture in which a proper spatial resolution is
needed.
Another possible, particularly interesting development is aimed
at the realization of the functions described above directly on yarns. 34–36