# Rapid and Cost-Effective Fabrication and Performance Evaluation of Force-Sensing Resistor Sensors
## 4 Discussion  
This study aimed to investigate the potential of using easily accessible materials, such as pencil graphite and silicone sealant, for fabricating force-sensing resistor (FSR) sensors. The findings revealed that hand-made sensors, particularly those created using a mixture of 9B pencil graphite and silicone sealant, demonstrated performance characteristics comparable to commercial FSR sensors like the Interlink FSR-402 and Flexiforce A201 series. Figure 10: Continuous pressurization and decompression load voltage. (**a**) 9B + silicone sealant mixed, (**b**) Interlink FSR-402, and (**c**) Flexiforce A201-1. The load is the force applied to an area of 10 mm \(\times\) 10 mm, which is equivalent to pressure. The measurement interval is 1000 ms (one data point per second). One of the primary advantages identified in this research is the cost-effectiveness of using pencil graphite and silicone sealant. These materials are not only inexpensive but also widely available, which makes the fabrication process highly accessible. This stands in stark contrast to commercial FSR sensors, which can be prohibitively expensive for large-scale deployment or cost-sensitive applications. The study highlighted the importance of material composition in determining sensor performance. The piezoresistive properties of pencil graphite were effectively utilized to create sensors that respond to applied force with changes in resistance. Furthermore, the inclusion of silicone sealant provided the necessary mechanical stability and flexibility, allowing the sensors to withstand repeated loading and unloading cycles without significant degradation. However, some limitations were observed. The hand-made sensors exhibited higher noise levels during voltage output measurements compared to their commercial counterparts. This indicates that further refinement in the fabrication process, such as more precise mixing of the graphite powder and silicone sealant or improved assembly techniques, could enhance sensor performance. Moreover, graphite sensors can have issues such as limits of high resistivity, fair sensitivity, and moderate response time, as [PERSON] et al. [34] noted when developing graphite-on-paper-based strain sensors. Thus, a highly conductive graphite pencil on a smooth paper substrate can be used to minimize these restrictions. In future research, the limitations should be carefully examined and considered to improve the performance of our FSR sensor. Our experiments also showed that the conductivity of 9B pencil lead is higher than that of 4B pencil lead, resulting in better performance in terms of output voltage during continuous pressurization. The 9B FSR sensor displayed a clear increase in output voltage as force was applied, indicating its sensitivity and responsiveness. In contrast, the 4B FSR sensor exhibited minimal change in output voltage under force, suggesting that it does not possess the necessary characteristics to function effectively as an FSR sensor. Velostat, a material commonly used in wearable devices, showed some promise due to its resistance-changing properties under flexing and force. However, the changes in output voltage were small and inconsistent, indicating that while Velostat can detect force, it may not be ideal for precise force measurement applications. The mixture of 9B pencil lead powder and silicone sealant emerged as the most promising material combination for creating an FSR sensor. This mixture demonstrated a voltage output that was proportional to the applied and decompressed force, closely mirroring the behavior of commercial FSR sensors. This suggests that the mixture of 9B pencil lead powder and silicone sealant can effectively measure force and respond to load changes in a manner similar to commercial sensors. In addition, [PERSON] et al. [35] found that the roughness of pencil graphite can play an important role in enhancing pressure sensitivity and response time of the pressure sensor.