Low-Power Water Flow Measurement With Inductive Sensing Reference Design
Created: Jul 25, 2018
The TIDA-01228 design uses TI's CC1350 SimpleLink Ultra-Low-Power Dual-Band Wireless MCU and the FemtoFET CSD23285F5 P-channel transistor to implement an LC-sensing subsystem to detect disc rotation with minimal cost and dual-band RF functionality. Mechanical flow meters with impellers are the most popular type throughout the world, and electronic add-on solutions already exist. Low-power operation is achieved by using the CC1350's integrated Sensor Controller Engine to interface to the LC sensing circuit and calculate the flow rate based upon the pulses generated when the meter disk rotates. This allows the ARM® Cortex® M4 MCU and RF subsystem of the CC1350 to stay in low-power sleep mode for longer periods of time. The TIDA-01228 introduces a novel approach by integrating a true dual-band wireless subsystem with low-cost LC sensors to deliver a single-chip flow measurement solution that also offers wireless communications in both the Sub-1 GHz ISM band and the 2.4-GHz band. This single-chip approach provides a highly affordable and physically compact solution for customers developing AMR modules. Popular AMR solutions such as wM-Bus or Sigfox can now be combined with a standard Bluetooth low energy connection to a smart phone or tablet as a powerful and easy-to-use human interface for local configuration and data readout.
This reference design demonstrates a highly-integrated solution for this application using an inductive sensing technique enabled by the CC1350 SimpleLink™ Wireless MCU and FemtoFET™ MOSFET. This reference design also provides the platform for integration of wireless communications such as wireless M-Bus, Sigfox™, or a proprietary protocol. Water utility providers who wish to add Automatic Meter Reading (AMR) capability face the choice of replacing all of their existing meters or installing a simple electronic add-on module, which will accurately measure the water flow rate and wirelessly transmit the results. Such add-on modules can provide the least expensive solution to provide AMR features to consumers.