# Rapid and Cost-Effective Fabrication and Performance Evaluation of Force-Sensing Resistor Sensors
## 1 Introduction
[23; 24; 25] focused on the use of pencil graphite as an active material in electrochemical sensing, emphasizing its cost-effectiveness, simplicity, and environmental benefits. Despite these advances, the discussed sensors exhibit several limitations. Humidity sensors based on 6B pencil graphite, while sensitive, may suffer from inaccuracies due to the manual fabrication process, which involves human hand-pressure rather than a controlled, automated system, leading to variability and affecting consistency. Pressure sensors, although flexible, may face mechanical durability issues under prolonged stress and have limited effectiveness in extreme pressure conditions. Electrochemical sensors are prone to surface fouling, impacting accuracy and requiring frequent maintenance, and may have lower sensitivity compared to more advanced materials such as modified carbon nanotubes. Gas sensors may encounter selectivity challenges in complex gas mixtures and are sensitive to environmental factors like temperature and humidity, necessitating additional calibration. On-skin electronics may experience reduced adhesion over time, particularly in moist environments, potentially affecting comfort and signal stability, and may encounter interference from other electronic devices, impacting biosignal detection accuracy. Furthermore, paper substrates have been effectively utilized in conjunction with pencil graphite. [PERSON] et al. [26] highlighted the mechanical strength and versatility of cellulose-based paper, making it suitable for forming various 2D or 3D shapes, and noted its compatibility with carbon and silicon sealant mixtures for FSR sensors. [PERSON] et al. [27] used paper substrates to fabricate sensors for measuring the bending of fluidic elastomer actuators, leveraging the paper's ability to support conductive materials. [PERSON] et al. [28] presented a high-performance, degradable all-paper-based pressure sensor. [PERSON] et al. [29] described a paper-based supercapac pressure sensor for wrist arterial pulse monitoring, emphasizing its high sensitivity for wearable healthcare. [PERSON] et al. [30] introduced a fully paper-based piezoresistive pressure sensor for wearable electronics, focusing on its high performance under varied pressures. [PERSON] et al. [31] developed a capacitive flexible pressure sensor with silver nanowires and polydimethylsiloxane (PDMS), showcasing its potential in human-related measurements and artificial skin applications. [PERSON] et al. [32]discussed a multilayered, flexible, paper-based pressure sensor for human-machine interfacing, emphasizing its sensitivity and flexibility. However, the primary limitations of these studies are potential long-term stability issues, mechanical durability concerns, and complex fabrication processes, which may affect scalability and production costs, impacting their practical application. The objective of this study is to develop a cost-effective and rapid fabrication method for force sensors using readily available materials. To validate the feasibility of this approach, we compare the performance of these handmade sensors against commercial FSR sensors across various applications. The study addresses the following key aspects: (1) analysis of the material composition of commercial FSR sensors to identify suitable alternatives; (2) fabrication of FSR sensors utilizing 4B and 9B pencils along with silicone sealant; (3) evaluation of the electrical and mechanical properties of the fabricated sensors; and (4) comparison of the performance characteristics with those of commercial FSR sensors. The primary compositional difference between 4B and 9B pencils lies in the graphite-to-clay ratio, with 9B pencils containing more graphite, resulting in softer and darker lines, while 4B pencils contain more clay, making them harder and easier to control.