scholarly journals Wirelessly Powered Light and Temperature Sensors Facilitated by Electrically Small Omnidirectional and Huygens Dipole Antennas

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 1998 ◽  
Author(s):  
Wei Lin ◽  
Richard W. Ziolkowski

Wirelessly powered, very compact sensors are highly attractive for many emerging Internet-of-things (IoT) applications; they eliminate the need for on-board short-life and bulky batteries. In this study, two electrically small rectenna-based wirelessly powered light and temperature sensors were developed that operate at 915 MHz in the 902–928-MHz industrial, scientific, and medical (ISM) bands. First, a metamaterial-inspired near-field resonant parasitic (NFRP) Egyptian axe dipole (EAD) antenna was seamlessly integrated with a highly efficient sensor-augmented rectifier without any matching network. It was electrically small and very thin, and its omnidirectional property was ideal for capturing incident AC wireless power from any azimuthal direction and converting it into DC power. Both a photocell as the light sensor and a thermistor as the temperature sensor were demonstrated. The resistive properties of the photocell and thermistor changed the rectifier’s output voltage level; an acoustic alarm was activated once a threshold value was attained. Second, an electrically small, low-profile NFRP Huygens antenna was similarly integrated with the same light- and temperature-sensor-augmented rectifiers. Their unidirectional nature was very suitable for surface-mounted wireless power transfer (WPT) applications (i.e., on-body and on-wall sensors). Measurements of the prototypes of both the light- and temperature-sensor-augmented omni- and unidirectional rectenna systems confirmed their predicted performance characteristics.

Author(s):  
Sangyeop Lee ◽  
Ruibing Dong ◽  
Shinsuke Hara ◽  
Kyoya Takano ◽  
Shuhei Amakawa ◽  
...  

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1067
Author(s):  
Karla Jaimes Merazzo ◽  
Joseba Totoricaguena-Gorriño ◽  
Eduardo Fernández-Martín ◽  
F. Javier del Campo ◽  
Eva Baldrich

Smartphones are becoming increasingly versatile thanks to the wide variety of sensor and actuator systems packed in them. Mobile devices today go well beyond their original purpose as communication devices, and this enables important new applications, ranging from augmented reality to the Internet of Things. Personalized diagnostics is one of the areas where mobile devices can have the greatest impact. Hitherto, the camera and communication abilities of these devices have been barely exploited for point of care (POC) purposes. This short review covers the recent evolution of mobile devices in the area of POC diagnostics and puts forward some ideas that may facilitate the development of more advanced applications and devices in the area of personalized diagnostics. With this purpose, the potential exploitation of wireless power and actuation of sensors and biosensors using near field communication (NFC), the use of the screen as a light source for actuation and spectroscopic analysis, using the haptic module to enhance mass transport in micro volumes, and the use of magnetic sensors are discussed.


2000 ◽  
Vol 279 (4) ◽  
pp. R1316-R1320 ◽  
Author(s):  
Mary D. Coyne ◽  
Christina M. Kesick ◽  
Tammy J. Doherty ◽  
Margaret A. Kolka ◽  
Lou A. Stephenson

The purpose of this study was to determine whether core temperature (Tc) telemetry could be used in ambulatory women to track changes in the circadian Tc rhythm during different phases of the menstrual cycle and, more specifically, to detect impending ovulation. Tcwas measured in four women who ingested a series of disposable temperature sensors. Data were collected each minute for 2–7 days and analyzed in 36-h segments by automated cosinor analysis to determine the mesor (mean temperature), amplitude, period, acrophase (time of peak temperature), and predicted circadian minimum core temperature (Tc-min) for each cycle. The Tcmesor was higher ( P ≤ 0.001) in the luteal (L) phase (37.39 ±0.13°C) and lower in the preovulatory (P) phase (36.91 ±0.11°C) compared with the follicular (F) phase (37.08 ±0.13°C). The predicted Tc-min was also greater in L (37.06 ± 0.14°C) than in menses (M; 36.69 ± 0.13°C), F (36.6 ± 0.16°C), and P (36.38 ± 0.08°C) ( P ≤ 0.0001). During P, the predicted Tc-min was significantly decreased compared with M and F ( P ≤ 0.0001). The amplitude of the Tc rhythm was significantly reduced in L compared with all other phases ( P ≤ 0.005). Neither the period nor acrophase was affected by menstrual cycle phase in ambulatory subjects. The use of an ingestible temperature sensor in conjunction with fast and accurate cosinor analysis provides a noninvasive method to mark menstrual phases, including the critical preovulatory period.


Author(s):  
J S Ashwin ◽  
N Manoharan

An embedded based power plant system is used for checking the environmental condition based on different sensor. The microcontroller is fixed inside the boiler which is a turbine, to monitor the status and the information is passed through GSM. In this project we proposed the main water tank supplies number of boilers. The water level is controlled by a water level sensor, each evaporator has two channels, one is delta other one is outlet and the channels' valves are controlled by some temperature sensors composed in each package. From the GSM modem, the user will get the present status of the boiler level by sending a radiator ID number as message. When the temperature inside the boiler exceed the threshold value it will indicate as a warning to the concerned authority person to take the immediate step.


2017 ◽  
Vol 12 (3) ◽  
pp. 695-700 ◽  
Author(s):  
Dominic Ehrmann ◽  
Monika Spengler ◽  
Michael Jahn ◽  
Dea Niebuhr ◽  
Thomas Haak ◽  
...  

Background: Temperature sensors are an objective way to assess adherence to diabetic footwear. Good adherence is essential for the prevention of diabetic foot problems. Little is known about the long-term course of adherence in patients at risk for diabetic foot problems. Method: A temperature sensor was incorporated into the specialized footwear of patients with type 2 diabetes after their first plantar ulceration. Kaplan-Meier curve was used to analyze when patients started to become nonadherent (not wearing the footwear for two straight weeks). Gender effects on adherence were also analyzed. Results: 26 patients with a mean observation time of 133.5 days could be analyzed. Mean wearing time of diabetic footwear was 4.2 ± 3.6 h/day (Mdn = 3.4 h/day; interquartile range = 0.5-7.0 h/day) and on 51% of the days patients did not wear their footwear at all. Kaplan-Meier curve revealed that the mean time of adherence was 27.5 weeks. Men achieved a mean time of adherence of 30.5 weeks, while women only achieved 14 weeks. However, due to the small sample size, this difference was not statistically significant. Conclusions: Temperature sensors revealed a low long-term adherence to diabetic footwear. Women seemed to be at a higher risk for earlier nonadherent behavior. Adherence to diabetic footwear should be closely monitored and tailored intervention strategies should be developed.


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