Water meter reference design with two LC sensors, using the Extended Scan Interface (ESI)

Battery-powered water meters face a challenge: continuously measuring water flow information while consuming as little power as possible. The EVM430-FR6989 used in this design uses a MSP430 FRAM-based microcontroller, which can provide 100uA/MHz active mode current and 450nA standby mode current, support real-time clock function, and integrate low-power analog and digital peripherals. Additionally, the MCU offers virtually unlimited write endurance, fast/low power writes and data flexibility. This reference design demonstrates how to use the integrated Extended Scan Interface (ESI) on a microcontroller to achieve ultra-low power consumption (versus the same detection method using external circuitry). In a water meter design, if coupled to the LC rotation detection sensor (supplied), the ESI continuously detects thruster rotation while the rest of the microcontroller is in a low power mode. The design automates the measurement process and reduces CPU involvement by using the ESI integrated in the MSP430 MCU, which helps reduce overall power consumption.

characteristic

• ● Supports the use of 2 LC sensors to detect rotational motion (including rotation direction)
• ● Ultra-low power consumption compared to external hardware solutions
• ● GUI for setting up and calibrating ESI
• ● Convenient to install the sub-sensor board corresponding to the MCU target board
• ● Variable speed motor control board can use metal plates to simulate flow
• ● RF sockets supporting low-power RF extensions (sub-1GHz or 2.4GHz ZigBee) are available