This fully tested reference design demonstrates a low-power solution for electronic measurement of water flow through a mechanical meter and provides a single-chip platform for flow measurement and wireless communications. The design is ideal for water meter automatic meter reading (AMR) modules that add wireless communications to existing mechanical meters. The RF subsystem supports standard protocols such as wireless M-Bus or proprietary protocols in the Sub-1 GHz ISM bands. This reference design offers the ability to accurately read the mechanical rotation from longer distances: and provides greater reliability. The ultra-low power consumption reduces the battery requirement and extends product lifetime.