Temperature Sensor Prototype Research Articles

An ultrasonic and temperature sensor prototype using fuzzy method for guiding blind people

A blind person must be protected from direct contact with unknown high-temperature objects in the surrounding environment. A system is needed to be able to detect the location and temperature of objects without direct contact. Ultrasonic sensors are used as object distance detectors and infrared temperature sensors are used as object temperature detectors without any direct contact. This system is processed with ATMega328 and information is conveyed to the user via buzzer sound signals and DC motor vibrations. The system as a whole is planted in a glove designed specifically to facilitate the user in using the tool.

Raman spectroscopy and resistance-temperature studies of functionalized multiwalled carbon nanotubes/epoxy resin composite film

Nowadays, flexible sensors and electronics accelerate the development of conductive polymer composites (CPCs). Carbon nanotube (CNT)-based epoxy resin CPCs could lead to possible breakthroughs for engineering applications because of the relatively high mechanical stiffness of this material. In this work, a flexible temperature sensor prototype was prepared from multiwalled carbon nanotubes (MWNTs)/epoxy resin CPC film. The flexible interdigital electrode was integrated to decrease the resistance of the composite film from 10 MΩ to 300 kΩ. The strain in the MWNTs was quantitatively measured by Raman spectroscopy. Temperature dependence of the composite film resistance exhibited clear positive temperature coefficient (PTC) and negative temperature coefficient (NTC) phenomena. The glass transformation temperature of the composite was determined by dynamic mechanical analysis. Finally, a segmented model concerning the entire resistance-temperature relation of the composite was established, and a possible mechanism was proposed according to the synergistic effect between tunneling conduction and electron thermal fluctuation. The segmented equation provided here may be useful for further sensor optimization and theoretical modeling based on such MWNTs/epoxy resin CPCs.

Low-Cost Wireless Temperature Measurement: Design, Manufacture, and Testing of a PCB-Based Wireless Passive Temperature Sensor.

Low-cost wireless temperature measurement has significant value in the food industry, logistics, agriculture, portable medical equipment, intelligent wireless health monitoring, and many areas in everyday life. A wireless passive temperature sensor based on PCB (Printed Circuit Board) materials is reported in this paper. The advantages of the sensor include simple mechanical structure, convenient processing, low-cost, and easiness in integration. The temperature-sensitive structure of the sensor is a dielectric-loaded resonant cavity, consisting of the PCB substrate. The sensitive structure also integrates a patch antenna for the transmission of temperature signals. The temperature sensing mechanism of the sensor is the dielectric constant of the PCB substrate changes with temperature, which causes the resonant frequency variation of the resonator. Then the temperature can be measured by detecting the changes in the sensor’s working frequency. The PCB-based wireless passive temperature sensor prototype is prepared through theoretical design, parameter analysis, software simulation, and experimental testing. The high- and low-temperature sensing performance of the sensor is tested, respectively. The resonant frequency decreases from 2.434 GHz to 2.379 GHz as the temperature increases from −40 °C to 125 °C. The fitting curve proves that the experimental data have good linearity. Three repetitive tests proved that the sensor possess well repeatability. The average sensitivity is from repetitive measurements conducted three times. This study demonstrates the feasibility of the PCB-based wireless passive sensor, which provides a low-cost temperature sensing solution for everyday life, modern agriculture, thriving intelligent health devices, and so on, and also enriches PCB product lines and applications.

Barium Strontium Titanate Thin Film Growth with rotational speed variation as a satellite temperature sensor prototype

Barium Strontium Titanate(BST) is a promising material for sensor devices such as temperature and infrared sensor. BaxSr1-xTiO3 thin films with affordable Si substrate were prepared by chemical solution deposition method and spin coating technique for 30 seconds with variation in rotation speed (3000 rpm, 5500 rpm and 8000 rpm). A high baking temperature at 8500C has been used for 15 hours during the annealing process. The thickness of BST film was calculated via gravimetric calculation. USB 2000 VIS-NIR was used to characterize the optical properties of BST thin film. The obtained reflectance curve showed that the most reflected wavelengths were in the range of 408-452 nm respectively. The result of the optical film characterization is very important for further development as a sensor in satellite technology.

Effects of thermal annealing on SEBS/MWCNTs temperature-sensitive nanocomposites for the measurement of skin temperature

The monitoring of skin temperature is essential for many applications, especially in sport and medicine. In this work, a flexible and wearable temperature sensor was obtained thanks to the controlled incorporation of multi-walled carbon nanotubes (MWCNTs) in an elastomeric matrix based on a poly(b-styrene-b-(ethylene-co-butene)-b-styrene) matrix. Thermal annealing at 155 °C for 4 h decreased the percolation threshold of the nanocomposite by about 40% thanks to the strong modification of the copolymer phase structure, which provided a more effective percolative network. The proposed temperature sensor prototype showed a very high linearity (R2 = 0.9987) and reproducibility (standard deviation < 1%) for temperature variations within the physiological regime.

Calibration and performance assessment of a temperature sensor prototype using a 1-point calibration procedure

This study aims to assess the relevance of 1-point calibration procedure, within the framework of the development of a new telemetric temperature sensor. The criteria used for performance assessment were the level of accuracy, and the time of inertia of the temperature sensor prototype (TSP) tested. First, the stability of the calibration bath was assessed. Then, the accuracy of 16 prototypes was evaluated for 7 target temperatures (ranging from 29 °C to 45 °C). Finally, the inertia of TSP response was evaluated while increasing and decreasing the bath temperature. The difference between prototype and target temperature increases as bath temperature moves away from 37 °C; however, the accuracy of the sensor conforms to applicable standards. Most TSP remain in the range of ±0.2 °C for each temperature level tested, but a linear, decreasing slope is observed; prototypes underestimate high temperatures and overestimate low temperatures. Data from time of inertia assessment show that probes were within the range of ±0.2 °C from the target temperature with a maximal delay of 150 s which satisfy standard norms. However, results indicate that a 1-point calibration procedure of the sensors appears non optimal, a 2-point calibration procedure should be performed to avoid the observed temperature data slope.

Non-invasive continuous cerebral temperature monitoring in patients treated with mild therapeutic hypothermia: An observational pilot study

Aim of the study To investigate if body temperature as measured with a prototype of a non-invasive continuous cerebral temperature sensor using the zero-heat-flow method to reflect the oesophageal temperature (core temperature) during mild therapeutic hypothermia after cardiac arrest. Methods In patients over 18 years old with restoration of spontaneous circulation after cardiac arrest, a temperature sensor that uses the zero-heat-flow principle was placed on the forehead during the periods of cooling and re-warming. This temperature was compared to oesophageal temperature as the primary temperature-monitoring site. To assess agreement, we used the Bland–Altman approach and Lin's concordance correlation coefficient. Results From September 2008 to April 2009, data from 19 patients were analysed. The median time from restoration of spontaneous circulation until temperature sensor application was 53 min (interquartile range, 31; 96). All sensors were removed when a core temperature of 36 °C was reached. These measurements were in agreement with oesophageal temperature measurements. No allergic reaction, rash or other irritation occurred on the skin around or under the probes. Bland–Altman results showed a bias of −0.12 °C and 95% limits of agreement of −0.59 and +0.36 °C. Lin's concordance correlation coefficient was 0.98. Conclusions Body temperature measurements using a non-invasive continuous cerebral temperature sensor prototype that uses the zero-heat-flow method accurately reflected oesophageal temperature measurements during mild therapeutic hypothermia in patients with restoration of spontaneous circulation after cardiac arrest.

Practical polarization maintaining optical fibre temperature sensor for harsh environment application

A reflection spot temperature sensor was proposed based on the polarization mode interference in polarization maintaining optical fibre (PMF) and the phenomenon that the propagation constant difference of the two orthogonal polarization modes in stressing structures PMF is sensitive to temperature and the sensing equation was obtained. In this temperature sensor, a broadband source was used to suppress the drift due to polarization coupling in lead-in/lead-out PMF. A characteristic and performance investigation proved this sensor to be practical, flexible and precise. Experimental results fitted the theory model very well and the noise-limited minimum detectable temperature variation is less than 0.01 °C. The electric arc processing was investigated and the differential propagation constant modifying the PMF probe is performed. For the demand of field hot-spot monitoring of huge power transformers, a remote multi-channel temperature sensor prototype has been made and tested. Specially coated Panda PMF that can stand high temperatures up to 250 °C was fabricated and used as probe fibres. The sensor probes were sealed within thin quartz tubes that have high voltage insulation and can work in a hot oil and vapour environment. Test results show that the accuracy of the system is better than ±0.5 °C within 0 °C to 200 °C.