A Miniature Fabry–Pérot Fiber Interference Sensor Based on Polyvinyl Chloride Membrane for Acoustic Pressure Sensing in Mid–High-Frequency Band

In this paper, a Fabry–Pérot interference fiber sensor was fabricated by using a Polyvinyl chloride membrane (20 μm in thickness) attached at the end of a ferrule with an inner diameter of 1.1 mm. In consideration of the vibration response of the membrane, the feature of the first-order natural frequency of membrane was analyzed by COMSOL Multiphysics. The acoustic sensing performance of the Fabry–Pérot fiber interference sensor was studied in air. The results reveal that the sensor possessed good acoustic pressure sensitivity, in the order of 33.26 mV/Pa. In addition, the noise-limited minimum detectable pressure level was determined to be 58.9 μPa/Hz1/2 and the pressure-induced deflection obtained was 105 nm/Pa at the frequency of 1 kHz. The response of the sensor was approximately consistent with the reference sensor from 1 to 7 kHz. All these results support that the fabricated Fabry–Pérot fiber interference sensor may be applied for ultra-sensitive pressure sensing applications.

Omnidirectional Fingertip Pressure Sensor Using Hall Effect

When grasping objects with uneven or varying shapes, accurate pressure measurement on robot fingers is critical for precise robotic gripping operations. However, measuring the pressure from the sides of the fingertips remains challenging owing to the poor omnidirectionality of the pressure sensor. In this study, we propose an omnidirectional sensitive pressure sensor using a cone-shaped magnet slider and Hall sensor embedded in a flexible elastomer, which guarantees taking pressure measurements from any side of the fingertip. The experimental results indicate that the proposed pressure sensor has a high sensitivity (61.34 mV/kPa) in a wide sensing range (4–90 kPa) without blind spots on the fingertip, which shows promising application prospects in robotics.

Rapid prototyping of a temperature, humidity, and pressure monitor electronic layer for Pressure Ulcer wound patch

Pressure ulcer is a result of relieving pressure from skin or underlying tissues, causing localized injuries. In this study, a prototype of an electronic monitoring layer that can be placed on top of the wound patch is designed. The electronic layer is comprised of four force-sensitive pressure sensors, and an integrated temperature and humidity sensor to monitor the activities surrounding the wound site. In the simulated wound bed experiments, the results indicated that the utilization of the Bosch BME280 I2C module, when placed on top of a gauze pad, can deliver accurate and real-time monitoring of the temperature and humidity values. Furthermore, the force-sensitive resistors (FSR) installed can be utilized to detect external pressure beyond the set allowable force applied of 32 mmHg or 700g. Therefore, the electronic layer assembled from commercially available sensors can be used to monitor temperature and humidity while being able to detect externally applied pressure in real-time. However, improvements in the size and flexibility of the electronic layer are necessary to reduce the discomfort that patients suffering from pressure ulcers will experience.