This paper presents a sensitivity-enhanced gas sensor based on a film bulk acoustic resonator (FBAR). It was designed and fabricated with micro through-holes in its top electrode for sensitivity enhancement. The sensor was driven by a Colpitts oscillator circuit, and the output signal had characteristics of a power of −2.6 dBm@3 V and a phase noise of −90 dBc/Hz@100 kHz. In order to test the pe...

Nanoporous polymeric transmission gratings are demonstrated to be an excellent platform for high-speed optical humidity sensing. The grating structures were fabricated with a modified holographic, polymer-dispersed liquid crystal (H-PDLC) system. The sensing mechanism was based on changes in the relative transmission associated with the adsorption and desorption of water vapour by nanopores. Th...

This work presents the design and implementation of a wireless sensor network (WSN) from first principles, i.e. without the use of commercial WSN platforms. Specifically, a modular multi-hop WSN was built for humidity, temperature and soil wetness measurements, towards precision agriculture applications. We describe the modules developed for radio communication, low-cost sensing, relaying and s...

Paphiopedilum armeniacum is level-one protected species. As the original habitat destruction, Paphiopedilum armeniacum is at the brink of extinction now. In order to monitor the environment of the endangered plants such as Paphiopedilum armeniacum, to master the real-time changes of their environment factors such as temperature, humidity, light intensity, the design is based on AT89C51, regarde...

This paper investigates multiple alternatives to predict environmental parameters (temperature and relative humidity) inside an intelligent container with the aim of the supervision of cool chains. A wireless sensor network will help us to measure those parameters in some distributed points of the closed space. To achieve the aim of fault detection and also total energy saving in the sensor net...

Factors most affecting the health risks in the world are food poisoning such as food contamination is a disease. While there are many factors affecting food poisoning typically changes in temperature and humidity, and monitoring temperature and humidity variability during transport and storage is very important. So we for the consumer to prevent food borne illness and food poisoning index monit...

A hygrometer is an apparatus that measure humidity. Modern electronic devices use temperature of condensation or change in electrical capacitance to measure humidity difference. Humidity sensors are employed to provide an indication of moisture levels in the environment. To measure moisture level, various technologies are used. A capacitive type moisture sensor consisting of nanoporous thin fil...

The humidity sensing characteristics of different sensing materials are important properties in order to monitor different products or events in a wide range of industrial sectors, research and development laboratories as well as daily life. The primary aim of this study is to compare the sensing characteristics, including impedance or resistance, capacitance, hysteresis, recovery and response ...

This paper presents a method for the remote interrogation of batteryless humidity sensors based on statistical estimations and three-dimensional beam scanning techniques. As a proof-of-concept demonstration, a Van-Atta reflectarray sensor is interrogated with a 24 GHz Frequency-Modulated ContinuousWave transceiver at various reading ranges. The extension of the proposed approach to passive or m...

Graphite oxide has been investigated as a possible room-temperature chemiresistive sensor of ammonia in a gas phase. Graphite oxide was synthesized from high purity graphite using the modified Hummers method. The graphite oxide sample was investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetry and differential scanning calorimet...