Fig. 8 shows the comparison between the knitted piezoresistive sensor signal during elbow bends, and the response obtained through an electrogoniometer by Biometric􀂓; both the signals have been acquired simultaneously.

Fig. 8: Signal derived by knitted piezoresistive fabric sensor (upper) and Electrogoniometer (lower) during fast elbow bends.

Printed piezoresistive fabric sensors exhibit a similar electrical behavior and they have been characterized in previous works, [6] [7].

The realization of a garment devoted to the analysis of human movements is an application of printed piezoresistive fabric, an example is showed in Fig. 9.

Fig. 9: Examples of garments for biomechanical monitoring.

From design and manufacturing perspective, a special process has been set up to realize biomechanical monitoring garments, where sensors and connections are realized with the same conductive materials. This choice has been adopted in order to solve a critical issue related to the connectivity between the coated strain sensors and the electronics, keeping the elasticity and wearability of garment. For this reason printing and cabling was realized before the cut and sew phase, by using a hybrid solution: coating on the sewing done with conductive flexible yarns that are used as conductive cables.

IV. CONCLUSION

In this work a description of novel sensors developed to be integrated in sensorised garments for monitoring vital signs and body gesture/posture has been presented. The main advantage ensured by these systems is the possibility of wearing them for a long period of time without discomfort. Several issues deriving from the employment of the new technology which has consented the realization of these unobtrusive devices have been addressed. Moreover, it has been pointed out the use of these sensorised garments as a valid alternative to existing instrumentation applicable in several health care areas. Finally, results on the performances of the sensing systems were briefly reported. The work continues toward potential commercial exploitation.