Resumen
Diabetic Foot Ulcers are ominous consequence of
Diabetic Foot. Only general preventive guidelines are available,
and ulcers happen with no previous notice. To develop a
multidimensional ulcer opening warning device: temperature,
pressure, humidity and friction are usually considered. We use
standard flexible Force Sensing Resistors FSR 402 to detect not only
plantar pressure, but also plantar bioimpedance. Since FSR
includes conductive electrodes covered by polymer films, the
interface with the subject can be considered a capacitive electrode.
A special bioimpedance detection circuit is required to inject
current using two homologous FSR 402 contacts and measuring the
resulting voltage from the other two contacts available. This circuit
is able to detect the cardiac activity from the foot sole. For the first
time, pressure sensors are used as bioimpedance electrodes.