Solar Inexhaustible Power Source for Wireless Sensor Node
ABSTRACT Currently the appearance of really low power wireless transceivers is motivating the use of renewable energies to power embedded wireless sensor nodes in many applications. Nevertheless, energy storage and its degradation still keep on being the main issues in the design of any battery powered device. We present an autonomous power source based on a new system architecture, which uses the energy scavenging to replenish two different rechargeable energy buffers instead of the conventional single one. Combining appropriately a degradable large backup battery (Lithium-Ion) and a shorter but non degradable storage element (Supercapacitor), the lifetime of the group can be widely extended to what we can call near perpetual operation, for such a changing technology. This paper analyses and describes the keys of the design and the optimal hardware selection to implement an inexhaustible power source. Finally we implement a real one that takes advantage of the sunlight energy and intelligently manages both energy buffers, without the human intervention and without depending on any programmable device like microcontrollers.
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ABSTRACT: The design of a fully autonomous and wireless actuator node ("wEcoValve mote") based on the IEEE 802.15.4 standard is presented. The system allows remote control (open/close) of a 3-lead magnetic latch solenoid, commonly used in drip irrigation systems in applications such as agricultural areas, greenhouses, gardens, etc. The very low power consumption of the system in conjunction with the low power consumption of the valve, only when switching positions, allows the system to be solar powered, thus eliminating the need of wires and facilitating its deployment. By using supercapacitors recharged from a specifically designed solar power module, the need to replace batteries is also eliminated and the system is completely autonomous and maintenance free. The "wEcoValve mote" firmware is based on a synchronous protocol that allows a bidirectional communication with a latency optimized for real-time work, with a synchronization time between nodes of 4 s, thus achieving a power consumption average of 2.9 mW.Sensors 01/2011; 11(1):329-40. · 1.95 Impact Factor
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ABSTRACT: Environmental monitoring applications demand wireless sensor networks to operate over a long period of time. Although energy consumption of these systems has been tremendously reduced, lifetime of sensor nodes is still limited by the capacity and lifetime of batteries used as energy sources. Energy harvesting, and in outdoor deployments particular, solar energy harvesting becomes a suitable way of powering wireless sensor nodes as their power consumption decreases. In this paper we address the feasibility of battery-less operation of wireless sensor nodes using solar energy harvesting at locations where the amount of solar radiation is severely limited and seasonal variations are large. We present two circuit architectures optimized for low energy leakage and evaluate their performance based on data gathered in a deployment during winter in Sundsvall, Sweden. We show that both architectures allow operation of sensor nodes even in the darkest period of the year. Furthermore comparisons between the two architecture designs are provided.Sensor Technologies and Applications, International Conference on. 07/2010;