Supercapacitor power unit for an event-driven wireless sensor node

This paper discusses supercapacitor based power unit for event-driven wireless sensor network node. In such nodes, most of the energy is consumed when transmitting or receiving data. Sleep-wake scheduling mechanism is an effective way how to prolong node´s lifetime. However, this mechanism can result in delays because a transmitting node has to wait until his neighbor wakes up. Another solution is event-driven communication model, where nodes communicate in case an event occurs. Although, events occur asynchronously, the node needs to send a keep alive message periodically. An event can be caused by very high temperature (indicating fire), or presence of movement in a surveillance system. Good communication pattern can reduce energy consumption. However, the main issue remains the design of network node power unit. We propose supercapacitor power unit circuit which is charged from solar cells and discuss a sensor node energy balance.