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Innovative Sensing Systems. A survey of the activities on advanced sensing systems for permanent monitoring carried out at Politecnico di Torino – Department of Electronics. M. Parvis , G. Perrone , A. Vallan. Contact person: G. Perrone, Dep. of Electronics, guido.perrone@polito.it.
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Innovative Sensing Systems A survey of the activities on advanced sensing systems for permanent monitoring carried out at Politecnico di Torino – Department of Electronics M. Parvis, G. Perrone, A. Vallan Contact person: G. Perrone, Dep. of Electronics, guido.perrone@polito.it
Technologies Fiber Optic Sensors • FOS market is limited by high prices, complexity, insufficient familiarity with fibers: • Plastic optical fibers → very low-cost • Glass fibers → innovative interrogators Data Acquisition Architectures • Distributed measurement systems: • Integration of FOS in wireless networks • Wireless low-power sensor networks
Fiber vs. Traditional Sensors • Fiber vs. mechanical sensors: • Lightweight, flexibility and versatility. • Resistance to corrosion. • Reduced invasive impact given the possibility to remote the control unit. • Fiber vs. electrical sensors: • Immunity to electromagnetic disturbances and discharges. • Impossibility to start fires or explosions. • Simplified remote operation since the same fiber can be used both for sensing and data transmission.
Civil and geotechnical engineering: Structural monitoring, landslide evolution, … Mechanics: Automation, monitoring of movable parts, valves, … Chemistry: PH measurement, detection of gases or of toxic products, … Applications Medicine and bioengineering: Physiological parameters, muscular force, …
Capabilities • Plastic and glass fiber sensors for: • Displacements • Non contact distance • Vibrations / accelerations • Strain - pressures • Chemicals (H, SOx, NOx) • Temperature • Electrical Field • Custom data acquisition systems • Wireless network of low-cost miniaturized sensors for real-time and off-line monitoring 10 International patents
Examples Displacement / crack monitoring Chemicals Vibrations Smart buttons and network of wearable sensors Deformations
Examples: Displacement Sensors • Up to 60 mm • Resolution: < 1/100 mm • Repeatability: < 1/20 mm Displacement sensors Vibration sensor
Examples: Displacement Sensors Field test in Venice with the support from Fondazione TorinoWireless LOCK
Examples: Deformations Low cost sensor able to measure distributed displacements with a sub-millimeter resolution based on the phase shift between transmitted and received signals along a fiber link.
Response to five pressure stimuli Output power, dB Samples Examples: Deformations Distributed sensor used to measure deformations in a lab model of a bridge. Variation of light polarization Prototype of the control unit
Examples: Deformations Fiber Bragg Gratings with custom interrogators Acoustic wave detection Structural monitoring
Examples: Vibrations Low cost sensor based on the spectral analysis of the received reflected power to measure the amplitude of vibrations independently from the surface reflectivity. • Resolution: < 1/1000 mm • High frequency capabilities (current tests up to 40 kHz)
Example: Network of Wearable Sensors Wireless network of low-cost wearable buttons for real-time and off-line monitoring of temperature and humidity 10 cent shaped button with temperature and humidity sensor, lithium battery and 2.4 GHz radio Example of biomedical application: skin temperature and humidity monitoring during daily life