Details

Autor(en) / Beteiligte

• Chang, Hsu-Feng
• Chang, Shyang-Jye

Titel

Development of a matrix-style pressure sensing pin-pad module with tactile feedback

Ist Teil von

• Sensors and actuators. A. Physical., 2024-10, Vol.376, p.115572, Article 115572

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2024

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Conventional key-based passcode entry systems, typically implemented through physical keyboards, are widely used for protecting and inputting personal data. However, these devices are vulnerable to attacks such as shoulder surfing. Therefore, this study proposes a matrix pressure capacitive sensing pin-pad for digital passcode entry based on pressure levels. The capacitive pressure sensing component is composed of copper foil electrodes and air dielectric, forming parallel plate capacitors, and assembled with an elastic mechanical structure. When a finger presses the electrode's elastic layer, the capacitance value changes as the electrode plate approaches. A square wave voltage signal is used as the excitation signal, and the pressure's magnitude can be recognized by distinguishing the voltage values passing through the sensing device. This device can sense finger pressure in the effective range of 0–20 kPa and can differentiate between light pressure (less than 10 kPa) and heavy pressure (greater than 10 kPa) ranges. When using this device to enter a digital passcode, the complexity of the passcode can be increased based on the pressure's magnitude. The study conducted two validation experiments. In the experiment with 33 participants to evaluate whether tactile feedback could improve the input accuracy of pressure passcodes, participants demonstrated only a 46 % accuracy rate in distinguishing tactile feedback. In the tactile feedback passcode input experiment, the device provides different tactile feedback based on the participants' pressure levels. The results show that without tactile feedback, the success rate of correctly entering the passcode was 58.6 %, while with tactile feedback, the success rate was 68.2 %, representing a 9.6 % increase in accuracy. In the shoulder surfing experiment, 17 participants were recruited to capture three different angles of entering composite passcodes, ultimately forming a 7-minute video containing 35 samples. Additionally, an online questionnaire experiment was conducted, collecting experimental data from 41 participants. The shoulder surfing success rate for numerical passcodes was as high as 80.5 %, while for pressure passcodes, it was only 47.1 %, demonstrating that composite passcodes can increase the success rate of shoulder surfing attacks. Furthermore, different angles did not significantly affect the success rate of shoulder surfing attacks. Therefore, the proposed pin-pad with tactile feedback and pressure-level digital passcode entry method can effectively resist shoulder surfing attacks, thereby improving passcode security. [Display omitted] •Pressure Pin-pad resists shoulder surfing.•Input passcodes without habit changes.•Capacitive pad with real-time feedback.