## 3 Results and Discussion
### Test Results with Hybrid Paper-Based Sensors  
The prepared sensors were tested to assess their suitability for indicating dynamic strains resulting from mechanical activity, as well as effects related to the functioning of the human body. Figure 6 illustrates the investigated sensors' current-voltage (U-I) characteristics for different contents of the AgNPs. A characteristic linear course was recorded in all cases, indicating that [PERSON]'s law was strictly satisfied for the experimental range tested. For the cases presented, the calculated coefficient of determination \(R^{2}\) was 0.999. As expected, the slopes of the straight lines, and therefore the electrical resistances of the tested samples, increase proportionally with a decrease in the concentration of the AgNPs used. In the case of sample #5, the added CNTs had no significant effect on the U-I characteristics, which do not differ significantly from those observed for reference sample #1. It is probably due to differences in the lengths of the CNTs and the fabricated AgNPs. Silver nanowires, being longer, are easier to form a conductive path with. Hence, nanowires' dominant influence on the sensors' electric conductivity mechanism was confirmed experimentally. The rectilinear course of the characteristics of all investigated samples also allows one to conclude that the influence of the thermal effect caused by the flow of electric current through the sensor is negligibly small. During the tests, instantaneous changes in the relative resistance of the sensors were observed, especially within the \(-15\) up to \(+160\%\) range. Figure 7 illustrates the response of the test system resulting from the cyclic loading and unloading of a 200 g weight onto the surface of sensor #1. After loading the weight, it remained on the sample surface for 20 s. A good representation of the forced activity waveform can be observed. The peaks observed in Figure 7 immediately after applying the weight are probably related to the dynamic deformation of the PDMS layer, which is then transferred to the hybrid paper substrate. In this situation, the hypothesis of an electro-tribological effect cannot be rejected either. However, this requires further experimental validation. After the test specimen is loaded or unloaded, a slight, progressive change in specific resistance of 0.02 is observed over time, caused by the gradual micro-deformation of the tested material. The recorded run indicates a relatively short response time duration. The problem is the results' repeatability, especially the return to starting reference conditions after the mechanical impulse has ceased. However, this does not exclude the possibility of  
Figure 5: Spectra of the synthesized silver nanowires: (**a**) XRD spectrum, (**b**) UV–Vis spectrum. using the sensor in question to indicate simple mechanical impacts, especially at low rates of change. Figure 6: Current-voltage characteristics of AgNPs-based sensors made on hybrid paper for different conductor materials concentrations. Figure 7: Effect of cyclic loading and unloading of sensor #1 using a 200 g weight. Figure 8 shows the recorded results of the mechanical stimulation of a flexible element on which surface the sensor was attached. The mechanical perturbations were induced by a metal rod attached to the shaft of a DC motor spinning at a frequency of approximately 0.35 Hz. The applied unit pulse induced intense vibrations, which then quickly disappeared. The sampling frequency of the signal equal to 1000 Hz was then used to represent the acquired response more clearly. The recorded waveforms are due to inertial forces occurring during damped oscillations and are in line with the observations of other authors [32]. In the case studied, good repeatability of the recorded results was observed. Similar results from this part of the study can be used in the future to analyze the dynamic behavior of the systems studied. Figure 9 shows the effect of cyclic finger pressure on sensor #4, implemented according to two scenarios.