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Logging data from Milone eTape

Home › Forums › Environmental Sensors › Logging data from Milone eTape

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    • 2025-04-07 at 3:48 PM #19029
      Eric Booth
      Participant

        Hi –

        I am a newbie to the world of Arduino/MayFly and would like to create a system to regularly log the output from a Milone eTape sensor that will be installed on the side of a flume outdoors. This is the sensor: https://milonetech.com/shop/ols/products/xn-standard-etape-assembly-75a-a8ed96

        I have contacted Milone and it sounds like the pre-calibrated sensor with the 0-3.3 VDC resistance to voltage output module would be the way to go for highest precision. This unit has a 3-pin JST connector for power, ground in, and analog signal out.

        My question is what is the best way to connect the 3-pin JST connector to a MayFly board? Based on other forums (like this one), it sounds like it should connect to the MayFly’s ADS1115. But how exactly does that happen? Any help would be much appreciated!

      • 2025-04-07 at 10:57 PM #19032
        neilh20
        Participant

          Hi Eric – I’ve purchased and looked at using the eTape.

          I was just wondering what made you think they are “calibrated” – that is the “0.0” markings relates to a defined voltage.  Usually this is shown for a calibrated sensor.  Similarly for a Full Scale relates to a known Voltage.?

          looking at the graphs,  they describe “0-5VDC Linear Resistance to Voltage Module PN-05V00199 REV 2” but no graphs of 0.0 to V

          https://img1.wsimg.com/blobby/go/ab87a52f-5721-46e1-a348-7722f5ddcf97/downloads/0-5%20VDC%20Module.pdf?ver=1737319366040

          Be interested if you find that they have it calibrated .

        • 2025-04-08 at 2:56 PM #19033
          Eric Booth
          Participant

            Thanks for the response, Neil. I’m basing the idea that the sensor is calibrated on the following response from Milone when I asked about the difference between the standard voltage divider setup and the other more expensive (+$45) output modules:

            “<span data-olk-copy-source=”MessageBody”>If you go with the standard voltage divider, each sensor would have to be characterized/calibrated individually.  We calibrate sensor assemblies with the 0-3.3V/0-5V output modules in house before sending them out. Therefore, the latter will give you the best accuracy.”</span>

          • 2025-04-08 at 9:17 PM #19034
            neilh20
            Participant

              Good to hear. and definitely very interested in use with a flume.  What range of water depth measurement are you looking for and depth accuracy of measurement.

              Typically, because  ADCs are not good around 0.0V and rail – the Sensor range from 0.0 to full range, the Voltage range is from 10%Rail to 90%Rail (eg 0.3V to 3.0V for 3.3VDC rail) and typically wants to be ratiometric. That is the ADC voltage VREF is the same as that used by the sensor.  The other way of adjusting that is that the measuring device has a greater range than the actual range of measurement. That is 0.0  is less than the flume entrance.

              Resistance  varies with temperature (as everything in the universe varies with temperature)- so they haven’t listed what the temperature dependency is.   It might not be much in the water, and may need a reasonable shield for that out the water.

              How are you looking to power it, Are you looking to report it wirelessly?   Standard ModularSensors is best effort in both cases.

               

            • 2025-04-15 at 2:57 PM #19040
              Eric Booth
              Participant

                Sorry for the delay. I’m planning to use it in an H-flume that has a maximum depth of 0.45 meters. It looks like precision is listed as 0.25 mm but I’m okay with accuracy closer to 2 mm.

                And thanks for the sensor range info. I’ll plan to install the eTape in a probe well attached to the flume that extends below the flume entrance elevation. I will plan to test it for changes in temperature (air and water).

                I’m hoping to power it directly from the MayFly with a LIPO battery. And yes, I’m hoping to lean on the ModularSensors library even though the eTape sensor is not listed as a supported sensor: https://github.com/EnviroDIY/ModularSensors?tab=readme-ov-file#supported-sensors

                Any help on how to navigate that process? Thanks in advance!

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