This paper presents the design principles underlying the video nodes of long-lifetime wireless networks. The hardware and firmware architectures of the system are described in detail, along with the system-power-consumption model. A prototype is introduced to validate the proposed approach. The system mounts a Flash-based field-programmable gate array and a high-dynamic-range complementary metal-oxide-semiconductor custom vision sensor. Accurate power measurements show that the overall consumption is 4.2 mW at 3.3 V in the worst case, thus achieving an improvement of two orders of magnitude with respect to video nodes for similar applications recently proposed in the literature. Powered with a 2200-mAh 3.3-V battery, the system will exhibit a typical lifetime of about three months. © 2011 IEEE.