Recent developments in microcontroller, radio transceiver, and energy harvesting device design now permit wireless sensor nodes to operate indefinitely from power scavenged from their environment. Many algorithms for conventional sensor networks assume that nodes run directly from non-rechargeable batteries and therefore attempt to conserve energy rather than carefully exploiting it when available. Effectively incorporating energy harvesting into wireless sensor network deployments, and simulations, poses unique problems related to energy-awareness and performance optimization. This paper presents a characterization of energy devices for sensor nodes and outlines their use in simulation and deployment. A case study of an energy-aware sensor node operating from a photovoltaic module and supercapacitor is explored. This paper also presents a modular software and hardware architecture which encourages energy-aware algorithm design and allows the automatic configuration of energy-aware sensor nodes.