## 4 Discussion
### Comparative Analysis of the Proposed Piezoresistive Chest Band with Similar Devices
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Work** & **Number of Sensors** & **Mean Error** \\ \hline
**Proposed Chest Band** & 1 & 3.13\% a  \\ \hline [PERSON]. [PERSON] et al. [21] & 1 & 3.53\%/3.99\% \\ \hline [PERSON] et al. [64] & 1 & 2.99\% \\ \hline [PERSON] et al. [29] & 2 & 2\% \\ \hline [PERSON] et al. [65] & 1 & 0.5\% \\ \hline [PERSON] et al. [30] & 2 & 2.06\% \\ \hline [PERSON] et al. [66] & 2 & 1.45\% b  & \(-\)3.49 a  & \(-\)9.51\% c  \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Performance comparison of the developed RR monitoring device with other similar systems presented in the scientific literature. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Work** & **Sensing** & **Processing Unit** & **Sampling** & **Availability of** & **Wireless** \\
**Device** & & **Frequency [Hz]** & **Communication** & **Wearability** \\ \hline [PERSON] et al. [21] & A201 FlexiForce & Arduino Pro Mini & & & \\ sensor & (ATMega32U) & 50 & Bluetooth (HC-05) & Medium \\ \hline [PERSON] et al. [56] & PDMS/Graphene & Arduino Uno & & & \\ sensor & (ATMega328p) & 1000 & WiFi (ESP8266) & Low \\ \hline [PERSON] et al. [57] & MEMS pressure & DL850 Acquisition & & & \\ sensor & \(\text{board}/\text{PC}\) & 1000 & No & High \\ \hline [PERSON] et al. [24] & piezoresistive fabric & STM32F401 RCT6 & 1000 & BLE (HC-08) & Medium \\ \hline [PERSON] et al. [58] & MEMS LCP pressure & NI-USB6003 \(\text{board}/\text{PC}\) & 2000 & No & Low \\ \hline [PERSON] et al. [29] & Strain sensor & NI-USB6003 \(\text{board}/\text{PC}\) & 1000 & Bluetooth & High \\ \hline C. [PERSON] et al. [25] & Silver conductive & PIC18F46J50 & 60 & & \\ \hline
**Proposed Chest Band** & LTT-SLPA-20K & SAMD21G18 & 1000 & BLE (JDY-23) & High \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Table summarizing the piezoresistive RR sensors from the point of view of the used sensing device, processing unit, sampling rate, availability of wireless communication, and wearability. placed at strategic points (abdomen and ribcage), enabling more reliable detection of respiratory activity. However, the presented chest band employs a 12-bit Successive Approximation Register (SAR) ADC of the SAMD21 microcontroller, thus explain the reduced performance of our system compared to the aforementioned systems [23; 65]. Nonetheless, as stated below, a system upgrade involving a high-resolution ADC will significantly improve overall system performance, thus improving the performance of the proposed device to that of the best-performing systems described above. The presented chest monitor represents a ready-to-use, discreet, and complete solution for monitoring breathing parameters, unlike the other wearable systems reported in the literature, which comprise only the sensing and conditioning sections, and leave the acquisition to an external data acquisition (DAQ) board and the processing to a PC [23; 65]. In addition, the system in [66] uses two sensors realized with EeonTex fabric similar to that employed in this work (EeonTex LG-SLPA), placed on the chest and abdomen, resulting in a more intrusive solution than the proposed approach. From the performance point of view, our chest band obtains better performance when the user is standing than that presented in [66] (3.13% vs. 3.49% mean percentage error); nevertheless, the latter offers better performance when the user is seated. Considering the wearability of the designed device, it is very compact and light, and does not hinder the user's movements. In fact, it includes an electronic section with dimensions of 7 \(\times\) 3 cm and a very narrow (2 cm width) and light (just 5 g) piezoelectric sensor band. In addition, the device does not require any external electronic section, meaning the device is more practical and easier to use compared to the devices previously discussed [23; 24; 65; 66]. In conclusion, the presented chest band offers significant scope for reducing the mean error, thus enabling higher reliability in breathing activity monitoring.