Engineering a hardware platform for a Wireless Sensor Network (WSN) node is known to be a tough challenge, as the design must enforce many severe constraints, among which energy dissipation is by far the most challenging one. Today, most of the WSN node platforms are based on low cost and low-power programmable micro controllers, even if it is acknowledged that their energy efficiency remains limited and hinders the wide-spreading of WSN to new applications. In this paper, we propose a complete system level flow for an alternative approach based on the concept of hardware micro-tasks, which relies on hardware specialization and power gating to dramatically improve the energy efficiency of the computational part of the node. Early estimates show power saving by more than one order of magnitude over MCU-based implementations.