A relative humidity sensor was fabricated by exploiting an evanescent wave (EW) on a U-bent tapered plastic optical fiber (POF) coated with zinc oxide (ZnO) nanorods. The POF was tapered manually using a polishing method to a diameter of 0.5 mm, a length of 5 cm, and a radius of 5 cm. ZnO nanorods were synthesized using a hydrothermal method and grown on the POF by a seeding process for 12 h. A significant response of the sensor was observed when the sensor was exposed to 35 to 90%RH due to the intense chemisorption process and changeable relative index in the POF. The sensitivity and resolution of the sensor have been improved by factors of 1.23 and 2.18, respectively, compared to the conventional tapered POF sensor without ZnO coating. Besides, the ZnO-coated sensor also exhibited better repeatability properties in terms of output voltage when exposed to 35 to 90%RH for three repeated measurements. The obtained results revealed that the proposed new POF sensor has an excellent sensing performance as an RH sensor in terms of sensitivity, repeatability, and stability properties.

A novel tapered plastic optic fiber (POF) biosensor is proposed and demonstrated for monitoring limonene in different concentrations. The mechanism of this device is based on an increase in the light transmission of a sensor submerged in a higher-concentration limonene solution, which also reflects an increase in the refractive index of the sensor. The tapered POF was fabricated using the chemical etching method to accomplish different waist diameters of 0.6 mm, 0.55 mm, and 0.5 mm, with a fiber length of 10 cm and a 2 cm sensing region. An Arduino integrated development environment (IDE) program was used to drive the voltage values from the photodetectors to obtain the measurements. As the limonene concentration solution varied from 20% to 100%, the output voltage of the sensor increased linearly, showing a sensitivity of 0.295 V/%, 0.33 V/%, and 0.46 V/% for tapered waist diameters of 0.6 mm, 0.55 mm, and 0.5 mm, respectively. The proposed sensor is a low-cost solution measurement option with high sensitivity, while it also involves a simple and easy fabrication technique.

Technology advancement in photonics has progressively tailor human need in healthcare industries. Inventing a new medical device or application for the mental and health sectors have make disease diagnosis easier. Without prevention, the number of sufferers may rise quickly. Studies have identified a way to diagnose diabetes illness by measuring a person's acetone level. The existing blood test have inferiority in term of invasive and dangerous if not handled properly. In this report, acetone concentration has been detected using a simple, low-cost Polyvinyl Alcohol (PVA) coated glass substrate platform as a potential diagnosis tool for diabetes patient. Based on the experiment results, the proposed sensor exhibits exceptional sensing performances for acetone detection in term of sensitivity, linearity, repeatability, stability and hysteresis

To utilize the evanescent wave on a plastic optical fiber (POF), a humidity sensor was fabricated based on a tapered POF with a loop shape and coated with zinc oxide (ZnO) nanorods. The POF was tapered manually to a diameter of 0.90 mm by using the polishing method. ZnO nanorods were synthesized using the hydrothermal method. The obtained results revealed that the increase in the length of the tapered POF loop coated with ZnO nanorod had provided an excellent sensing performance as an RH sensor in terms of sensitivity and repeatability properties.

This paper describes the design and development of a measuring tool using a mobile robot. At present, contractors are measuring distances using measuring tape which has few limitations. This includes using of another manpower or a marking flag. The Robot Measuring System is designed to measure distances at multiple conditions such as smooth and rough surface. An optical quadrature encoder is used as a sensor to measure the distances while a program is installed in Arduino Uno for reading and data collection. Graphical User Interface (GUI) was created using Android software so that the movement of the robot can be controlled using a smartphone within a Bluetooth range. An experiment was conducted to test the reliability in terms of accuracy and precision. The best accuracy and precision were obtained when the robot speed is at 90 cm/s on the plain tiles, 80 cm/s on the tar road and 90 cm/s on the grass surface. The robot speed needs to be adjusted accordingly based on the surfaces in order to get an accurate result. This paper proved that the robot measuring system was successfully designed, implemented and analyzed.