Monitoring systems for elderly require a compromise between reduced size and operational autonomy. The latter to get a system as independent as possible and to fit with our application needs for daily use. Our patch i...Monitoring systems for elderly require a compromise between reduced size and operational autonomy. The latter to get a system as independent as possible and to fit with our application needs for daily use. Our patch is developed as a surveillance system for old people;we chose to equip it with a wireless charging system for greater ease of use, imperceptible in the everyday life and waterproofing. This paper presents the development of a printed receiver coil to be integrated in a wireless charger to be used in an elderly tracking patch. The proposed design is validated using simulation that presents a good agreement with measurement results: Simulation (@150 KHz: L = 10.74 μH;R = 3 Ω) and Measurement (@150 KHz: L = 10.8 μH;R = 3.16 Ω). The receiver coil is elaborated on a polyimide substrate in the cleanroom of our laboratory LAAS-CNRS (Laboratory for Analysis and Architecture of Systems-National Center for Scientific Research) and a PCB (Printed Circuit Board) charger prototype is fabricated to test its performances before the integration of the wireless charging property in the tracking patch. The proposed coil presents a good compromise between small size and efficiency. For a charging current of 7.5 mA, this coil can ensure the recharging of the patch up to a distance of 4.8 mm between the Qi transmitter and receiver which is more than enough for our application.展开更多
Compared with the traditional techniques of forest fires detection,wireless sensor network(WSN)is a very promising green technology in detecting efficiently the wildfires.However,the power constraint of sensor nodes i...Compared with the traditional techniques of forest fires detection,wireless sensor network(WSN)is a very promising green technology in detecting efficiently the wildfires.However,the power constraint of sensor nodes is one of the main design limitations of WSNs,which leads to limited operation time of nodes and late fire detection.In the past years,wireless power transfer(WPT)technology has been known as a proper solution to prolong the operation time of sensor nodes.In WPT-based mechanisms,wireless mobile chargers(WMC)are utilized to recharge the batteries of sensor nodes wirelessly.Likewise,the energy of WMC is provided using energy-harvesting or energy-scavenging techniques with employing huge,and expensive devices.However,the high price of energy-harvesting devices hinders the use of this technology in large and dense networks,as such networks require multiple WMCs to improve the quality of service to the sensor nodes.To solve this problem,multiple power banks can be employed instead of utilizing WMCs.Furthermore,the long waiting time of critical sensor nodes located outside the charging range of the energy transmitters is another limitation of the previous works.However,the sensor nodes are equipped with radio frequency(RF)technology,which allows them to exchange energy wirelessly.Consequently,critical sensor nodes located outside the charging range of the WMC can easily receive energy from neighboring nodes.Therefore,in this paper,an energy-efficient and cost-effective wireless power transmission(ECWPT)scheme is presented to improve the network lifetime and performance in forest fire detection-based systems.Simulation results exhibit that ECWPT scheme achieves improved network performance in terms of computational time(12.6%);network throughput(60.7%);data delivery ratio(20.9%);and network overhead(35%)as compared to previous related schemes.In conclusion,the proposed scheme significantly improves network energy efficiency for WSN.展开更多
文摘Monitoring systems for elderly require a compromise between reduced size and operational autonomy. The latter to get a system as independent as possible and to fit with our application needs for daily use. Our patch is developed as a surveillance system for old people;we chose to equip it with a wireless charging system for greater ease of use, imperceptible in the everyday life and waterproofing. This paper presents the development of a printed receiver coil to be integrated in a wireless charger to be used in an elderly tracking patch. The proposed design is validated using simulation that presents a good agreement with measurement results: Simulation (@150 KHz: L = 10.74 μH;R = 3 Ω) and Measurement (@150 KHz: L = 10.8 μH;R = 3.16 Ω). The receiver coil is elaborated on a polyimide substrate in the cleanroom of our laboratory LAAS-CNRS (Laboratory for Analysis and Architecture of Systems-National Center for Scientific Research) and a PCB (Printed Circuit Board) charger prototype is fabricated to test its performances before the integration of the wireless charging property in the tracking patch. The proposed coil presents a good compromise between small size and efficiency. For a charging current of 7.5 mA, this coil can ensure the recharging of the patch up to a distance of 4.8 mm between the Qi transmitter and receiver which is more than enough for our application.
文摘Compared with the traditional techniques of forest fires detection,wireless sensor network(WSN)is a very promising green technology in detecting efficiently the wildfires.However,the power constraint of sensor nodes is one of the main design limitations of WSNs,which leads to limited operation time of nodes and late fire detection.In the past years,wireless power transfer(WPT)technology has been known as a proper solution to prolong the operation time of sensor nodes.In WPT-based mechanisms,wireless mobile chargers(WMC)are utilized to recharge the batteries of sensor nodes wirelessly.Likewise,the energy of WMC is provided using energy-harvesting or energy-scavenging techniques with employing huge,and expensive devices.However,the high price of energy-harvesting devices hinders the use of this technology in large and dense networks,as such networks require multiple WMCs to improve the quality of service to the sensor nodes.To solve this problem,multiple power banks can be employed instead of utilizing WMCs.Furthermore,the long waiting time of critical sensor nodes located outside the charging range of the energy transmitters is another limitation of the previous works.However,the sensor nodes are equipped with radio frequency(RF)technology,which allows them to exchange energy wirelessly.Consequently,critical sensor nodes located outside the charging range of the WMC can easily receive energy from neighboring nodes.Therefore,in this paper,an energy-efficient and cost-effective wireless power transmission(ECWPT)scheme is presented to improve the network lifetime and performance in forest fire detection-based systems.Simulation results exhibit that ECWPT scheme achieves improved network performance in terms of computational time(12.6%);network throughput(60.7%);data delivery ratio(20.9%);and network overhead(35%)as compared to previous related schemes.In conclusion,the proposed scheme significantly improves network energy efficiency for WSN.
