With the advent in technology, wireless sensor networks are used to gather information and monitor data in the inaccessible and remote areas where wired network is not feasible. Due to limited power back-up, sensor network cannot be deployed on wider scale. Processing is recommended within network to reduce communication overhead and energy consumption. Low power analog processing circuits integrated within sensor nodes are suitable for this task. This paper reviews analog circuitries for processing of data to improve energy efficiency in addition to low power networking protocols and security solutions.