This paper discusses the design considerations and trade-offs for solar energy harvesting modules, emphasizing their impact on harvesting efficiency. It highlights the differences between solar harvesting and conventional battery-based systems and outlines the desired features of a solar harvesting module to enable harvesting-aware power management. The authors present the design, implementation, and performance evaluation of Heliomote, a plug-and-play solar energy harvesting module for Berkeley/Crossbow motes. Heliomote autonomously manages energy harvesting, storage, and power routing, providing real-time solar and battery state information through a simple one-wire interface. Experimental results demonstrate the feasibility of near-perpetual operation of outdoor sensor networks using solar energy harvesting. The paper also reviews related work, including energy-efficient design techniques for sensor networks and various harvesting modalities. It details the design choices for the Heliomote, including the selection of solar panels, energy storage technologies, and harvesting circuit design, and evaluates the module's performance through experiments. The authors conclude that environmental energy harvesting is a viable option for energy-constrained embedded systems, and their work shows the potential for near-perpetual operation of outdoor sensor networks.This paper discusses the design considerations and trade-offs for solar energy harvesting modules, emphasizing their impact on harvesting efficiency. It highlights the differences between solar harvesting and conventional battery-based systems and outlines the desired features of a solar harvesting module to enable harvesting-aware power management. The authors present the design, implementation, and performance evaluation of Heliomote, a plug-and-play solar energy harvesting module for Berkeley/Crossbow motes. Heliomote autonomously manages energy harvesting, storage, and power routing, providing real-time solar and battery state information through a simple one-wire interface. Experimental results demonstrate the feasibility of near-perpetual operation of outdoor sensor networks using solar energy harvesting. The paper also reviews related work, including energy-efficient design techniques for sensor networks and various harvesting modalities. It details the design choices for the Heliomote, including the selection of solar panels, energy storage technologies, and harvesting circuit design, and evaluates the module's performance through experiments. The authors conclude that environmental energy harvesting is a viable option for energy-constrained embedded systems, and their work shows the potential for near-perpetual operation of outdoor sensor networks.