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EV-FLOWMETER-ARDZ Sensor for Flow Rate Metering


The EV-FLOWMETER-ARDZ sensor is an advanced and efficient solution for flow measurement, suitable for utility and industrial applications. The ultrasonic time-of-flight technology, coupled with the integrated functions of the MAX35101 time-to-digital converter, addresses the limitations of mechanical flow meters and offers improved accuracy and longevity.


  • High accuracy flow measurement for billing and leak detection
  • Time-to-digital accuracy down to 20 ps
  • Measurement range up to 8 ms
  • Two (2) single-stop channels
  • High accuracy temperature measurement for precise heat and flow calculations
  • Up to four (4) 2-wire sensors
  • PT1000 and PT500 RTD support
  • Maximizes battery life with low device and overall system power
  • Low 10 μA ToF measurement and <125 nA duty-cycled temperature measurement
  • Event-timing mode reduces host microcontroller


  • Ultrasonic heat meters
  • Ultrasonic water meters
  • Ultrasonic gas meters
  • Utility metering
  • Environmental monitoring

Block Diagram

Hardware Design

Components and Connections

Peripheral Connectors

The following standard connectors are provided on the board for customer to use:

  • Launch up and down ultrasonic sensor terminal block headers
  • PT1000/500 platinum resistive temperature detectors (RTD) terminal block headers
  • Arduino connector

Sensor Probe

When using this Arduino board, a general-purpose ultrasonic flow rate sensor can be used. An example of a probe is the Flow Transducer with Pipe (Model:HS0003) from Audiowell Sensor Technology, as shown below:

Item Specifications
Resonant Frequency 975 ±30 kHz
Resonant Impedance ≤ 110 Ω
Static capacitance 1350 ±20% pF
Pressure Resistance 1.6 Mpa
Permanent Flowrate 2.5 m³/h
Max Flowrate 5.0 m³/h
Min Flowrate 0.050 m³/h
Environmental Temperature +5°C ~ +55°C
Diameter DN20

For temperature measurement, this board supports up to four 2-wire PT1000/500 platinum resistive temperature detectors (RTD) and the connections can be seen on the diagram as shown below:

An RTD sensors or a dummy sensor (1k Resistor) for each terminal are required in order to run and capture the flow rate.

Digital Interface (Arduino)

The Arduino interface is a standardized digital interface for various digital communication protocols such as SPI, I2C, and UART. These interface types were standardized by Arduino, which is a hardware and software company. Complete details on the PMOD specification can be found here.

Push Button

The board provides a button, S1, to test tamper detection through its CMOS digital input.


The EV-FLOWMETER-ARDZ can be used with the MAX32670-SX-ARDZ Base Board, which is a long-range wireless radio development platform based on MAX32670 ultralow power Arm Cortex-M4 microcontroller and SX1261 RF transceiver.

Using these platforms together enables users to design solutions based on low-power, long range proprietary radio communication technique that is suitable for customized heat/flow meters.

To learn more about the Long Range Wireless Radio solution developed by Analog Devices, visit the AD-MAX32SXWISE-SL Long Range Wireless Radio Development Kit User Guide

System Setup

PHASE 1: Hardware Setup

Note that this setup only applies for MAX32670-SX-ARDZ Base Board. Users may use a different base board or microcontroller, however the firmware built for this demo application cannot be used as this is specifically designed for the MAX32670-SX-ARDZ.

Equipment Needed

  • One (1) MAX32670-SX-ARDZ Base Board
  • One (1) EV-FLOWMETER-ARDZ Sensor Node
  • One (1) MAX32625PICO Rapid Development Platform with 10-pin ribbon cable
  • One (1) CR123A Battery or any equivalent external DC power supply (+3 V to +4.7 V)
    • Note that this is not included in the kit
  • One (1) Micro USB to USB cable
  • Host PC (Windows 10 or later)

  1. Insert one CR123A battery (3 V to 4.7 V) into the battery holder (BT1 connector) of the MAX32670-SX-ARDZ Base Board.

    Make sure to check for the battery polarity in the BT1 connector, refer to the figure below. The DS3 LED will light up indicating that you have inserted the battery correctly and that power is provided in the base board.

  2. Connect the EV-FLOWMETER-ARDZ Sensor Node to the MAX32670-SX-ARDZ Base Board by aligning the corresponding Arduino headers on each board.
  3. Connect the MAX32625PICO programming adapter to the MAX32670-SX-ARDZ Base Board through the 10-pin ribbon cable.

    Make sure that the MAX32625PICO programming adapter has been flashed with the correct image before connecting it to the MAX32670-SX-ARDZ Base Board. If you do not know how to load the image, click on the instructions below:

    How to flash the firmware image in the MAX32625PICO

    How to flash the firmware image in the MAX32625PICO

    1. Download the firmware image: MAX32625PICO Firmware Image for MAX32670
    2. Do not connect the MAX32625PICO to the MAX32670-SX-ARDZ Base Board yet.
    3. Connect the MAX32625PICO to the Host PC using the micro USB to USB cable.
    4. Press the button on the MAX32625PICO. (Do not release the button until the MAINTENANCE drive is mounted).
    5. Release the button once the MAINTENANCE drive is mounted.
    6. Drag and drop (to the MAINTENANCE drive) the firmware image.
    7. After a few seconds, the MAINTENANCE drive will disappear and be replaced by a drive named DAPLINK. This indicates that the process is complete, and the MAX32625PICO can now be used to flash the firmware of the MAX32670-SX-ARDZ Base Board.
  4. Connect the MAX32625PICO programming adapter to the Host PC using the micro USB to USB cable.

Once you have completed this setup, proceed to PHASE 2 found in ADI Long Range Wireless Radio Software User Guide.


Design and Integration Files

EV-FLOWMETER-ARDZ Design Support Package


  • Schematic
  • Bill of Materials
  • Layout
  • Fabrication Files

Help and Support

For questions and more information about this product, connect with us through the Analog Devices Engineer Zone.

/srv/ · Last modified: 03 Apr 2024 04:37 by Joyce Velasco