3.5. Wireless Monitoring of Human Gait

The Laboratory Virtual Instrument Engineering Workbench (LabVIEW VI, manufacturer National Instruments, Austin, TX, USA) is used as a system-design platform and development environment to display the collected data in a numerical and graphical representation (Figure 2d). The application of LabVIEW VI software v.2015 is primarily dedicated to monitoring the real-time signals from sensors via Bluetooth communication. Figure 2a shows testing socks and three SF sensors with CNF piezoelectric material. Testing socks are coupled with an electronic controller (ESP 32, manufacturer Espressif Systems, Shanghai, China) that is the low-power system on a chip microcontroller (Figure 2b,c) used to sense the foot pressure through the analog to digital conversion (ADC) port. The sensors were stitched on socks in 3 locations shown in Figure 2a (the toe, midsection and heel), using stainless steel conductive thread. The conductive thread helps to transfer the current and does not affect the human skin. Figure 2c,d shows that the microcontroller was covered up with the 3D-printed case for safety purposes. The volunteer testing with the developed sensors and sensing data collection through Lab view software is presented in Figure 2e [Video S1: movement analyses].

(a) The three SF-based sensors with CNF stitched in the socks by means of conducting thread; (b) Electronic controller unit; (c) Electronic controller unit connected with sensors; (d) Electronic controller unit covered with the 3D printed case; (e) Sensors testing with a volunteer and LabVIEW software [Video S1: movement analyses].